Sorensen DCS Series - Modification and Repair Thread

methods

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Joined
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Since I have not contributed much of value recently - here is some value.

Purpose: To allow enthusiasts to buy used/damaged or (otherwise in need of repair) DCS supplies for charging and general geek use.

Background: Sorensen DCS supplies are expensive, high quality, rack mount, CV/CC Variable Lab Supplies. They run off of 120V or 240V single phase (an important point!) and they can be had for 1/10th the new cost on Ebay.

* They can stack in Series or Parallel (Very important point!)
* They can be remotely controlled via Analog (via Arduino) or GPIB etc (GPIB variants cost significantly more)
* They are laid out flat, very easy to reverse engineer, and come with a parts replacement list
* They have remote sense, remote interlock, current control, analog control, remote display, etc - all standard

I have rigged one of these supplies up with an Arduino to control and read back - it was trivial...


To work with: I have the following 1U supplies in hand, as well as a list of experience with other flavors

In Hand
DCS 60-18
DCS 60-18E
DCS 600-1.7

Experience with
DCS 8-125E
DCS 50-20E
DCS 300-3.5E

And in the 3KW variant 2U @ only 240V
DCS 8-350E
DCS 80-37E

Datasheet Links
http://www.programmablepower.com/dc-power-supply/DCS/Downloads.htm

...


Focusing in on what I have in hand (so what we can troubleshoot)

DCS is the series name
First number is the Voltage Limit
Second number is the Current Limit
(The later models have an E suffix)

The 1U (very carry-able) variant can provide either 1KW or 1.2KW (on either 120 or 240)
The 2U (Very heavy) variant can provide 3KW on single phase 240 (which can be made from 2pcs 120V outlet Single Phase...)


DCS 60-18E
This is my personal supply and the one I use to charge Ebikes with. I paid apx $350 shipped from Ebay. It arrived in good working order. Under heavy load it "squeals"... which is something we want to understand and repair.

DCS 60-18
This is the property of ChargePoint. It was purchased as part of a lot for Test Engineering Lab Use (bringup - not line test) and cost only $250. It has a bad fan and that is the most common failure and easiest to fix failure.

DCS 600-1.7
This is the property of ChargePoint. It was purchased for the same as the above and costs under $600 (Check pricing on HV supplies... they are expensive and hard to find... ESPECIALLY in a 120V flavor). This supply demonstrates a new failure mode which I have not encountered before: It can reach 500V... it can produce 1.7A... but not at the same time. I can reliably get about 420V at a few hundred mA out of it. This will also be an easy repair.

The most common out of the box failure modes are as follows:

EDIT:
Dry Caps
There are two very large 1800uF 200V caps wired in Series (on the 600V units)
These serve as voltage doublers for the AC input while the supply is wired in 120VAC mode
They serve as the filtering caps (for both 120V and 240V mode), and feed the chopper circuit.

With 120VAC in (and the selection P1 in either location) a failed supply will read apx 150VDC on the P2 jumper (across the stack). You should be reading more like 340VDC (RMS IN / 0.707, or Peak not RMS). 150V is the peak out a 120VAC RMS input*

In 240V mode the supply would reach 600V and 1.7A but NOT AT THE SAME TIME.
In 120V mode the supply would not reach 600V, but could reach 1.7A, But produced only about 100W




Dead Fan
This is the most likely... You can hear the fan clearly and the supply will work but overheat quickly. it is a few fasteners and 2 wires to replace the fan. The fan can be had for apx $20... or you can rig up whatever you have got around if you MUST. (I suggest doing it up back to factory)

* Red Light
If the Dsub25 "programming jumper" is not inserted into the rear of the supply it will not operate. There are a handful of jumpers that MUST be connected for the supply to work turn-key. The jumpers tell the supply things like the following:

- Front panel control or remote control
- Interlocked or not interlocked

The manual is quite explicit so I will not re-tread that information here. You just read the list of 25 pins and follow the directions as to which pins to short.

* The internal 240/120 jumpers are not set correctly
In this case, if internal is set to 120V, and you apply 240V... smoke can be seen. Make sure you see where it comes from.
If the internals are set to 240 and you apply 120 you will see a "weak response"

* Switch Settings Incorrect
There is a standard 8 leg rocker that needs to be set to a default
The manual covers it in detail

Squealing
This is supper common and ... appears... to not affect its output. I am sure that if you looked on the scope you would see the squeal - but for lipo charging, it has not affected me. I am MOST interested in solving this particular riddle.

V and A, but no Power
This one is new to me. I am certain that it is another super easy fix.

Slow Ramp Down - cooked sugar load
These supplies have great transient response. The price of that it some output loading... SHOULD you wire up a 50V or 120V lipo pack, then turn off the supply, the battery voltage back-feeds into the output impedance and smokes off the pull-down. I call that the sugar load... and it does not impact the supplies usefulness for charging or lab use (it just slows it down a bit). We want to identify which part is smoking off - buy a batch of them - and set up a "Sorensen Repair Kit".

Dead Bands in the dials
Unconfirmed - but I swear that while bringing one up for Boran I saw a dead band in the dial. It was weird... like a nick in the pot... allowing the voltage to momentarily dip (blip dip). Problematic possibly - would need to scope the output. They are 10 turn pots and could EASILY be swapped out.

General Cruft Buildup
Most of these supplies are from the 90's. They go into a rack, they get turned on, they stay turned on (or cycle once a day). The caps should all be shot out by now - but for what I want to do with them (charging - not dynamic response to changing load) they are fine so far and I have not had to replace any caps.

...

For charging - what we NEED - is an Ideal Diode.
Nick Long produces these and I have an open invoice to pick up another 50 of them (hopefully he still has them)
They are good to 100VDC and upward of 20A if done right
They have almost no forward drop, you can wire the sense wires downstream of them, so they have no impact on performance
They WILL stop your Lipo Pack from thrashing your supply should the breaker blow or should the supply be turned off before removing the active load.

A schottky diode will NOT SUFFICE. Even the huge variants get SUPER HOT and dump TONS OF HEAT.
Example:

100mV forward Voltage
20A forward current
V*I=W
100mV * 20A = 2W

Now... 2W does not SOUND like much... but it stacks up quickly... and requires a fan or major heat sinking to keep below 60C. For reference... most balance resistors see:

4.2V / 50mA = 84ohms
4.2V * 0.05A = 200mW
200mW requires an 800mW resistor MINIMUM - better to use a 2W resistor

Even at that tiny power you will find parts skyrocketing in temp.
(This is the sort of stuff that GreenHorn engineers do not understand. After they get done re-working their spice design... they then get to learn of the second order effects of major thermal stressing over time <fatigue failure>). Poor engineering is usually answered with fans... which result in single point failures involving fire and smoke... so... pay attention to what you are doing and always shoot for mill spec. (Mill Spec means all day, every day, working with multiple failures)

...

Good place to stop.
I am not going to fill this thread up with fancy pictures and half-wit remarks. I am going to use it as my notes section while I troubleshoot and repair these supplies.

Go buy one... and come along for the ride.

-methods
 
Reserved for the DCS 60-18E repair documentation
 
Reserved for the DCS 600-1.7 repair documentation


EDIT(3) FIXED


https://endless-sphere.com/forums/viewtopic.php?f=14&t=95184&p=1398780#p1398780

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file.php

file.php


EDIT(2) PCB Removed
https://endless-sphere.com/forums/viewtopic.php?f=14&t=95184&p=1398098#p1398098

EDIT(1)
First pics
(Because pics or it didn't happen...)

20180711_155022-2656x1494.jpg

20180711_154928-2656x1494.jpg
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ohhh kay...
We have a FUBAR plug :?

Thats a 240V 20A (like a NEMA 5-15, standard - but ... eh... totally not to be found in my house)

Solution is to swap the cord
Pop the top
Swap the jumper to 120V
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20180711_154935-2656x1494.jpg
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Looks like some JackTard named Schindler signed off on this :shock:
Closer inspection shows that it says 600V
And... it says 1.7A
BUT... it does not say 600V @ 1.7A
(Fleamarket shopping skills at work)

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20180711_154945-2656x1494.jpg
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In the back we have the jumper plug - sweet
Notice the output comes from a connector - not lugs - like you see on non-lethal supplies

Some shotty work on the plug - best to strain relieve it on the back so it can stack
(I was in a hurry... and these usually just sit on the top shelf of a bench 1 high)
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20180711_154958-2656x1494.jpg
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I have the tangle of wires right here - complete with a mating attachment on one side and trusty Anderson on the other.
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(Plug that bad boy into your 50V ebike pack and see what happens - lol...)
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EDIT (2) INTERNAL SUPPLY PICS
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First thing we look at when we remove the cover:

1) The paper insulator

How much dust do you see?
How much discoloration do you see?
Does it look original or replaced?
(This give you an idea of the number of hours the supply has seen.

20180714_100216-747x1328.jpg
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View attachment 9

...

Second we look at the Fan and overall cruft collection

1) Has the fan been replaced?
2) Is it a cots or aftermarket part?
3) was it a professional job?
4) How much dust do you see?

...

Well - in this unit the fan has been replaced
The job was not professional and the fan is not COTS
There is little to no cruft or dust
The paper has minimal dust markings (which could just mean it ran in a clean room)
There is discoloration -but not too much
The fan HAS been replaced so we know that it ran AT LEAST that many hours OR... it was originally a bad batch of fans (TBD).

...

View attachment 8
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Evidence of the above
Thats a shit tap job :mrgreen: The kind that unravels with time.

We either use heat shrink or Kapton tape these days.
We no longer use black tape - on any job - out of general principle.

If you must use black tape know that there are "grades" to the tape. Some is pure counterfeit garbage that has a poor temperature range and shit adhesive. Some is flexible and some rigid. Some thick and some thin. Some will hold for 20 years... and some wont even stick... so PAY FOR GOOD TAPE.

We use Kapton because it has a high dielectric strength, high quality adhesive which does not leave residue behind, it is "spaceship tape", it is cheap now days, it goes cold, it goes hot, it never fails you (if it is real Kapton - other polyimide tape works - but its case by case. I recently bought a large batch, for near free, on Amazon, and it worked great.

Kapton comes in many thicknesses... the thicker the more rigid - so I prefer the medium-thin (sorry - no mil spec) with several wraps. This tends to hold better and does not start to unpeel. It comes in wide and skinny. About an inch wide is what I work with most.

anyhow...
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20180714_100827-1328x747.jpg
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That is not the fan label I remember. Original units just had a stamp or marking. We will now review this particular fan for cost. To do this we start with Google, then Octopart.com

Model: UF90DPB12

First Google hit is Digikey - this is a legit supplier (if not a bit expensive)
We source from digikey regularly for high reliability R&D
https://www.digikey.com/product-detail/en/mechatronics-fan-group/UF90DPB12-H1S2A/1570-1174-ND/5209871

Octopart (which is usually not great for things like fans... but AMAZING for volume parts... REMEMBER THAT while price shopping)
- gives only the digikey source

So... $30 is a sure deal fix.
No idea how long it will last, how loud it will be, how much air it blows
Dont know, dont care

... moving on ...

Now - for some basics

* Supply Voltage
* Fusing
* Things that a clown can screw up

(ALWAYS, always always... start troubleshooting... at the MOST BASIC LEVEL. The biggest mistake I see from junior engineers is jumping in too deep before checking for baseline stupid stuff)

Are the fuses good?
Is the power wiring good, attached correctly, good crimps, good wall source (MEASURE IT), and is the jumper set correctly?

Did some meat-stick go in and just turn all the pots trying to "get it working"
This very well could be the case... that a meatball before you... just did something silly and stupid. NO AMOUNT of troubleshooting components will solve a poorly tuned setup!

So - this is why we look closely at the supply to see if someone has been in there mucking around.

1) Has it been overheated
2) Has someone fiddled with it
3) Who was it and what was their intent

We focus here first - as a virgin supply is much easier to troubleshoot
So - here we go

THE BASICS FIRST

Did you frocking plug it in?
Did you check the frocking fuses? :eek:
(Every time... no matter who you are... or how long you have been doing it. Just DO THE BASELINE - its a RULE - not an OPTION)
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View attachment 6
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Here is the voltage select plug
It has writing on it... if the supply has been cleaned you will not be able to read it.
The single loop is for 240V Single Phase
The double loop is for 120V Single Phase

You can build a "suicide plug"
A normal NEMA 5-15 house plug has a small slot and a large slot (as well as a round hole)
Round hole is GROUND (which if you follow the wires - gets tied back into Neutral at the box)

In the US - ground is bare copper or green
Neutral is White

The large slot is neutral - white
The small slot is line - black (sometimes red... but be careful... because read can be daisychain-switched)

The rational is that you do NOT want the neutral (which is effectively ground) wire of an appliance touching load - therefore it is larger and will not fit. This logic holds true.

So - You get two extension cables
You cut off the socket ends
You make a Y cable - it can be short and you can extend it
You tie the grounds together
You nip off the neutral (out of GP because we are not intending to use it here)
You now have 2 black wires... each "load"

If you plug this into two sockets side by side... you will have failed.
You will have 2 sources of 120V in parallel and a ground.
This will result in no potential between the two black wires

You can alternately - look at your fuse box - and determine which LEG of the incoming power you are on.
Your house has two legs (of three...) coming in
They are not perfectly out of phase but close enough
There is apx 240V potential between these two legs - and you can confirm this with a meter at the box

BIG RED WIRE
BIG BLACK WIRE
MAKUM biG VoLtAgE mmm?

So you plug a lamp into your socket
You flip all the breakers until that one turns off
Now you know - black wire or red wire

Now you go to the other side of the breaker... Say the first was black... so now the red
You figure out a plug in the house that feeds off of that breaker

You go and plug your Y calbe (with extensions) into these two plugs
BE frocking CAREFUL
As after you plug the first one in... you end up with a "hot end"

Hence the name suicide cable*

If you did it right (and I only described 80% here so that you wont try it...)
You will find
That your Y cable now has 240V of potential between the two black wires

You can wire those into the back of this supply
Or... You can flip that plug over and just wire in a standard 120V Single Phase

Got it?
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View attachment 5
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Here are your fuses
Check these.
Also check the third up by the fan (Android Picture Compress lost one of my pics... and duplicated another... buggy... grrr...)
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View attachment 4
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Here are your dip (shit) switches.
They are called dipshit switches because people often set them wrong
Confirm them

Confirm their operation first (which way is on, and what on means)
Then - confirm they are in the correct orientation
Its important (especially for diagnosing a bricked supply. These things work... and these switches can make it NOT WORK)
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View attachment 3
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Pay attention to details - like these mounting tabs
The one on the right has become loose and rotated out of position
Fix it
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20180714_100525-1328x747.jpg
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And here are our pots.
We will now confirm the switch positions
Confirm the pot locations
Confirm that the pots do what they are supposed to do (i.e. one is not shot out... which COULD cause problems)
and... onward

(Remember - I have never done this before - I have no idea how this will turn out or what to do next. This is simply how an engineer engineers... or at least how this engineer engineers. Ideally I would just cozy up next to someone who is an expert and suck their juices in 4 hours - instant expert - but in this case... we have to do it the old way - i.e. the hard way...

Just step by step
Logic and reason
Thinking it thru

... it is only a matter of time... I can solve any problem, anywhere. You need to believe that about your self to succeed. There is no Youtube video, there is no pamphlet from the church, ... there is just you and your thinker ... and your tools... and me...

and anyone else who decides to help*
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20180714_100708-1328x747.jpg
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I read

OFF
OFF
OFF
ON

OFF
OFF
OFF
ON

I read that from 1 to 8
I read that as "off rocker down"

I say that out loud while we troubleshoot... in case I have made a mistake... so the engineer studying can catch me.
(we never make mistakes on purpose, we make lots of honest mistakes, we always pretend we made a mistake on purpose for the understudy to catch, this keeps the understudy on their toes)

(If you are going to inject errors on purpose with an understudy - do it after 20 minutes are so - dont start that way - it tends to discourage them and make them feel like they are being tested or tricked. Get a good rhythm going, get your trust relationship solidified, them make a tiny mistake. Should your understudy space out at any time - terminate)

...

Someone either wants to learn bad
Or they are a waste of my time

...

So looking at the manual:




Ok - looks good to me
OFF is the same as OPEN
(Because closed means conducting)

And we see the same pattern
I have previously confirmed this and have seen the results so I will not dig deeper.

You would be wise to exercise the switches thru all of their permutations and confirm that each of them does what it is supposed to do*

-methods
 
Reserved for a listing of parts, materials, methods, and ways -

Links, prices, experiences, etc

...

EDIT(1)
The PARTS STORE!

Parts1.jpg

Hrmmm... well this one is a total rip... but for $200 buckolas you can get a FULL KIT of replacement parts :idea:
Yep
You could go down to the local rep
Write like 3 emails, go thru three people on the phone, pay like $20 per resistor, wait weeks and...

NO

Lol...

We get our parts in KITS
Kits come NEARLY COMPLETE
A kit is a broken supply*

...

Ya see's it?

... then... once you start getting "all advanced and stuff" you can take a good close look at the parts (which are not scuffed off) and find new and better replacements*

Caps - yea... caps are caps
Resistors ... no... this one only uses "magic resistors"

The transformers may get tough
The chips would definitely pose a problem
But...

Show me 1 good working supply
and... 1 fubar supply...
And I will show you a troubleshooting method
Point by point
That will tell you Good or Bad

...

Aim the probes one way - write it down
Aim the probes the other way - write it down
Try it powered and unpowered
... Looking for resistance and diode Vf while powered down
... Looking for voltages (and sometimes) currents while powered up
... Relative measurements -> and some absolute measurements - like TEMPERATURE

First - just get in there and look around
SNIFF AROUND
Turn it on... SNIFF SOME MORE

Get your 30X loop out and look close
Discoloration?
Cracks?
In the part or the pcb?

Measure... think about what the part is, what it is supposed to do... is it doing it?

Look at heat sink compounds and thermal conductivity - did it dry out?

Look at things that are dependent on the fan... did some douche cycle the thing on and off over and over with a dead fan trying to get some production test to pass???

Look for the BIG stuff first
OBVIOUS stuff

Dont pop the board - just the lid
Sneak up on it
Make sure ALL of your bases are covered and that you have SOME KIND of baseline to reference... NEVER just tear into it*

Tearing into something (without getting a baseline) results in not having any point of reference to measure your progress... or your momentum.... toward success or failure. Whatever the baseline is - capture it

Most importantly -
Any time you get lost in the bushes... GO BACK TO BASELINE!

Just solder the parts back in
Fire it back up
Get baseline

...

That proper troubleshooting
Anything else is just "tearing shit apart randomly and filling up the parts bin"
Lol

So

We have the AC side of things
We have the Output Section
We have the control Section
...

If you were to get serious about this you would disassemble at least 1 power supply - to the point where its parts can be "subbed in" to a rework unit to look for easy fixes. First we want to look at the system. Then at the component level. Then at the sub-system level... and only as a last resort - the actual piece parts

(Where Component refers to a stand alone outside tested part that drops in on an ICD)
(Sub-Components are just ... lower level.. but similar)
(Piece Parts are things like caps and resistors - where we might want to swap an entire PCB... but probably not on these units)

...

No I am not a repair guy
Hell No do I want to try and make a living at it

- I just know what works and what does not work for effective, accurate, precise troubleshooting. :D

-methods
 
Now that the stage is set...

I have no frocking idea what I am doing :oops:
So... if some expert stumbles along... PLEASE help out if you can.

* Common part numbers or failed parts
* Repair methods and ways
* General theory of operation
* Information about rebuilding (good as new)
* Anything you have got

... Fostering a DIY hankering for these supplies WILL result in turn-key sales later. Many on the fringe of our movement enjoy lurking the DIY but in the end - are happy to pay double for something that "just works". This should set you (and us) up for some cottage industry work that pays off, makes the world a better place, reduces waste, celebrates winning... and onward.

-methods
 
Battery Charging Guidance:

From the 1KW FAQ :: Sorensen FAQ

A7. Can we use the DCS1k to charge a battery?
Yes, but certain precautions must be taken. The supply is designed to supply current it does not have
the ability to absorb current. A blocking diode must be added to prevent current flow from the battery
through the supply. The anode of the diode connects to the positive output of the supply and the
cathode connects to the positive terminal of the battery. Use a diode with a PRV(peak reverse rating)
higher than the maximum charging voltage and a current rating higher than the maximum charge
current connected in s

If you choose to go the diode route I suggest some of the following:

1) Remove the cover, drill it, and directly mount your diode so as that it heat sinks into the housing. This will be a chassis mount diode, low forward Vf (100mV... not 300mV or 700mV). They look like this:

CMD1.jpg
CMD2.jpg

It is VERY important to note that the heat sink is OFTEN electrically connected...

They DO come isolated - and you CAN isolate them with Kapton - but:
In the case of the first
From this datasheet: https://www.mouser.com/datasheet/2/427/vs-123nq100pbf-40373.pdf
You can see that the cathode will see case.

In the case of the second - you can see from the pictures, that the Cathode is common with the case
(Same deal as our Mosfets in the Ebike Controllers.

So -
You COULD choose to just tie the case of your power supply to common ground. This has implications outside of the scope of this project - so instead - consider this:

1) measure the lug size
2) Over-drill by some number of mm
3) Identify or fashion an insulating sleeve (like we see on the mounting tabs of our TO-220 Mosfets) to keep the threads off of the case.
3) Utilize either a heavy strip of Kapton or an insulating washer on the nut side
4) Utilize a heavy strip of Kapton on the heat-sinking surface.
5) Apply liberal non-conductive heat sink grease
...
6) Since the fastening portion is down... consider picking up the Ground of the supply from INSIDE.
7) Think about mounting, consider mounting to the rear grill (instead of top) - think about rack-n-Stack
...

Now... What I would do... is NOT that :roll:

1) Open up the supply
2) Identify the Positive lead (or negative... but I prefer positive in THIS case)
3) Hodge in an Ideal Diode
4) Wire it back up

...

When you build your charge cable go HEAVY GAUGE
If you do this, you can just terminate your Sense leads right at the supply outlet and not run them out to the load
At low to moderate current - you will see nearly no effect

If you want true kelvin measurement - go ahead and run the 2 sense wires all the way down your cable.

I use Andersons for my cables
I link my cables in series, Y my cables, Parallel my cables... so... I am not interested in the mess of a 4 wire (or even 3 wire) measurement. I just sense at the ass of the supply, run phat cable, and not worry about it

(as CC mode falls into CV mode you will converge on zero cabling loss. Before then - in CC mode - it makes no difference what so ever... and error is on the side of safety (less voltage at the load battery)

Yepperz

eh...

Remember that as Voltage goes up the diodes have to STACK (internally... to meet standoff)
This means that for anything above say... tens of volts... you will be looking at MUCH greater Vforward losses

In the Example of say a 1KV supply - you could easily lose 2V forward
If you are running a 3KW supply - this 1KV could be at 3A - that is serious power!

2V * 3A = 6W
6W on just about anything.... can hit 60C in only a few seconds - and burn off in less than a minute
So... pay attention to your parasitic losses. Even tho they are a TINY fraction of your working power... they are a HUGE fraction of your cooling work... and they play a BIG PART in your reliability (should you lose heat sinking, fans, isolation, etc)

Eh
Nobody wants the negative of a 1KV source tied to case (trust me :shock: Frost your balls with that!)

-methods
 
Back to the Amtek website (who kindly provided these references... so if you are rich... learn from us, buy from them*)



This the part of the manual that gets our juices flowing
(in case your juices are not yet flowing... or they dont know where to flow... this is the section :idea: )

SO
THIS
Is why we like Sorensen (one reason)

Its a good manual
Made by engineers
For engineers

Its what I call a "win win" manual - as... opposed... to... a... "Greedy capitalist bastard manual"
Which will teach little, share little, and basically take on a "closed approach"

...

The closed approach is great for finished goods - like a cell phone... that you likely wont repair...
In the case of a two layer PCB Power Supply that is meant to last 100 years -
Yep - this is what documentation (GOOD DOCUMENTATION) looks like
(its a touch sparse... but one hell of a starting point)

...

Now... looky here kidz... WHO does this for you???

Theory of Operation Sorensen DCS Series 1kW and 1.2kW Supplies
3-4 M362500-01 Rev K

INPUT RECTIFIER AND INRUSH LIMITING
Input AC power passes from the rear panel AC connector (TB1) through an RFI filter consisting
of C1-6, R122, and common mode filter inductors L1, and L2 to the front panel power switch.
Both input lines are switched with one line (the neutral line of a 115Vac input) returning to the
A2 PCB and the input bridge rectifier CR35 via fuse F1. The other input line (the hot line of a
115Vac input) is connected to the remaining input of rectifier CR35 via front panel circuit
breaker CB1, relay K1 and the inrush limiter formed by parallel resistors R116, R116A and fuse
F2. Resistors R116, R116A limit the power-on inrush current to the main filter capacitors
C32(A,B,C) and C72(A,B,C) until it is shorted by K1 relay contacts. The time delay for K1
contact closure is determined by the time constant formed by capacitor C12, resistor R118 and
the gate threshold of FET Q6. Diode CR33 keeps the PWM shutdown input high until the relay
closes. Diode CR38 discharges C12 when the 12V auxiliary supply collapses and CR39
provides an inductive kickback path for the relay coil. During the inrush period, diode CR33
holds the PWM shutdown line high, disabling the power supply output until Q6 turns on.
Resistors R114 and R115 are bleeder resistors for the main filter capacitors. The rectified high
voltage dc from CR35 is supplied to the main switching FETs Q13-Q16 on the primary of the
power transformer T1 via fuse F3.

I randomly highlighted a few things in RED
Do
You
Realize how RAD it is that they are literally SPOON FEEDING you the circuit analysis WITH SILK SCREEN PART NUMBERS and flow analysis?!?!?!?

Nah....
You dont realize what you are looking at yet...

Not only will you not find this elsewhere ... but... you also wont find a radical education like this elsewhere.
This is bit for bit
Part by part
How you BUILD a super low cost, super reliable and awesome, variable power supply.

NOW

It is quite easy to build a fixed supply
I have reverse engineered MANY

It is a whole different can of beans to create a good quality, low cost, reliable VARIABLE power supply... and... they are spelling it out for us.

Any magic that happens in the processors - is pure trivial drivel.
Show me a hardware set that works... and I will show you code to run it
(We may have to blow up 20 or 30 of them... But I will damn sure get it working*)

-methods
 
A note on modding:
file.php


It is NOT my intent to modify the Sorensen Supplies to put out more than they are rated for:

(Say by increasing fan thru-put, swapping parts for lower losses, fiddling dividers and feedback to bump by 10%... 30%...)

I can tell you FOR CERTAIN that there is margin to be had in THIS design... especially the tidy little 1U units that run off of 120VAC. They are limited by what your wall can supply (they cant pull too much -) and this is the first place to explore. Companies build off of reference designs. Reference designs are RAD. Often designs are Value Engineered (or down select engineered) to meet a minimum spec at a maximum profit. It is NOT rocket science to Un-Value engineer... or Re-Jigger/Scale... to even Double the output.

Think I cant pull 2KW out of a Sorensen rated for 1KW
Oh yea I can.... :)

I can also fit a traffic cone - eh... in the trunk of my car :lol:

file.php


Note: KFF = Kentucky Fried Finger

You can now search the forum for 3 letter acronyms thanks to our rad staff :p
(Searching KFF comes up with some great pics and threads)
(Shorting out 18S High C into 12AWG WILL result in metal turning to liquid turning to gas and shrapnel).
(24S into 10AWG is better... and 1,000V into #0000 is BETTER YET)
(You have either blown shit up... or you know precisely shit... in this field... but that's about safety and this is about DIY)

-methods
 
Again from the manual...
(The damn best manual around - and one I model my documentation after...)

CAL1.jpg

Ahhh,.....
The Calibration knobs... :x

And - you dont even have to guess at it :eek:

hmmm...
Lets turn those up and down... (yea - thats where I will start - much more fun that staring at burnt components thru a 40X lens)

hhhmmm "Output Voltage Range"
hmmmm "Output Current Range"
Er - yep - those could be useful

Me wonders what happens if you swap the pots out (or the trim resistors) and just try to turn it up past 11 :?: :?: :?:
(its never that easy... but we still try - right?)


-methods
 
Tools...
Dont get started without them.

Here are a few:
* Quality Fluke DMM
(Please do not even post in this thread if you are using a $20 Autozone DMM. If you still dont understand the difference then pay me $20 and I will explain it. There is a BIG FROCKING DIFFERENCE)

* Fiddly bits for your dmm... gator clips, needle probes, sacrificial probes, replacement 10A and mA fuses

* A second meter* (it can be a cheapo) ... so that you can measure current while you measure voltage.
(A CA works great for this***)
(I have previously documented methods and ways for powering a CA then using it to measure voltage, current, power -etc)

* You will require a quality soldering station. NOT some busted 10W radio shack iron!!! Just throw that away. now. I mean it... into the garbage (not even the recycling... because there someone might find it). Smash it with a hammer. throw it away. K??

I use Weller products in the 50W to 80W range
On my desk now is a WESD51
Its cheap, has a digital display, has a simple knob, and just works

At work I have the newer model
Digital controls
80W instead of 50
Eh... I like the old one better. I am a knob sort of guy...

* With that iron you will need good 60/40 or 63/37 LEADED solder.
DO NOT
DO NOT DO NOT DO NOT
COME UP IN MY GARAGE TALKING ABOUT LEAD FREE SOLDER

Nobody... and I mean nobody... who is really doing this... prototypes lead free
For a thousand reasons... just use lead (until they further perfect the lead free)
It requires less heat, less flux, works on dirty parts, is more flexible, does not whisker out, and is rad

When we go into production we use lead free
When we prototype we use leaded
Case closed

* Use a sponge - you dont need any of that fancy tip cleaner shit. Tips last me years. Have 3 tip sizes... tiny for smd, medium for average work, and a HOG for dumping heat into heavy cable.

Thats all you need. A Weller Soldering station and a good roll of solder. You can pick those up local at Fry's

* De-Soldering
eh hem... different story

Wick - it works - but it takes a lot of flux (for de-soldering we buy tubs of jelly wax as well as different consistencies that flow)
Spring Suckers - meh - they could work
Bulb Suckers - yea - done a lot of work with them
Cheap De-Soldering Vacuum type - rad.. but mine would clog easy. They have a heat sink coil inside to catch solder - plugs easy

...

How I desolder?
well... first you need to remove as much of the thermal load as possible and reduce the number of points you need to keep hot.
So... Just cut the component off - thats the easiest
Leave enough of the legs to grab them with a set of Static tweezers** (You will need an amazon tweezers set - cost $20)

Since the component leg is tinned copper... and what we are trying to get rid of is lead tin... it turns out that the majority of the heat flows thru those (and does not sink in to the tweezers) so it is quite easy to

FLUX
Tin the tip
Touch the work
At the moment of reflow grab the leg
Pull the cut leg out of the assembly
THEN clean up with more flux and solder wick

Thats how I do most of my rework

So -
we are at:

DMM
Second DMM
Soldering station with lead solder and a wet sponge
Tweezer set

(If you dont know it I am putting together some "learning kits" for some local rats. Troubled kids that want to make car bombs and stuff. Hey - "Do it right, if your going to do it" is what I always tell them) :mrgreen:

-methods
 
Off to a meeting

Here is a pic of my kitchen table
Our supplies
and my sad... dead... hard drive (dropped my laptop :| )

20180711_113117.jpg

View attachment 1

20180711_113212.jpg

(now... I resized those on my Android... WHY did they still come out at MEGA resolution)
Sigh


-methods
 
Proof of viability -?

https://www.ebay.com/itm/Sorensen-DCS60-18-DC-Power-Supply-with-GPIB-Works/222949138157?hash=item33e8cddeed:g:6dkAAOSwsZJadzmq

That is an ad
(from a low count seller... but a quick check of his feedback shows that he just sold a Metcal to a happy customer... so if you speak the language... you know... this is the DEAL)

$315 shipped for a 60V 19A
WITH GPIB

(key word... WITH GPIB)

For our purposes here - we dont need GPIB... hell... we cant even afford GPIB cables or GPIB to USB converters... BUT -> If you are working in a lab you sure as shit can use GPIB. It makes life REAL EASY to just dial up some LabView and run a scripter

(For all my work the fist thing I gin up is a basic LabView "Event Biased State Machine" which initializes instruments then runs an ASCII script with basics - like this)

Sorensen 35.0 10000
Sorensen 30.0 5000
Sorensen 25.0 1000
Elgar 0.0 0

Where the first token represents the complexity behind addressing an instrument programatically
The second is the command - in this case voltage settings
The third is dwell until the next command

Like that
All day every day :)

-methods
 
now...
In the spirit of one of my teachers...

A word of caution

(note - updated the 600V and parts posts)

(story)
so...
Long ago I decided to teach myself Chemistry. I had been told many times - by many "self taught" types - that I could find all I need on the internet :eek:

oh kay
well.. . I found a lot alright..

A lot about how to make

Fireworks
Drugs
and how to refine precious metals

(hmmm... ok... apparently popular subjects)

Well - at the time I happened to know a gentleman who was in the scrapping business. He was hell bent on the idea of monetizing scrap, had a lot of scrap, and had a lot of information compiled around processing said scrap

Silver off of keyboards
Gold off of pins and PCB ends
...

To make a long saga into a short story - I set up a chemistry lab in my garage and went to work.

First tool needed?
Fuming Nitric Acid - or at least... Concentrated Nitric Acid
(which it turns you you dont really need... as concentrated nitric acid does NOTHING until you dilute it - story for another time)
...

So while reading on the subject of working with nitric acid I came across a book
Written by a lady (way back in the day) under the pen name of a man
it was quite the clever book...

as...

She did not divulge (until the 3rd or 4th chapter) how toxic and ferocious the Nitric Oxide (not be to be confused with Nitrous Oxide - which yes I have produced in sample quantities - this is Nitric: "Brown scary smoke")

Now... when you activate nitric Acid it fumes like a bastard
Wicked nasty redish brown smoke
Vapor of the devil it is... just a tiny breath full will knock you to the ground...

Just having anything metal (steel) in the room... results in near intimidate rust accumulation.
Like - rust starts growing
On the spot... like... after a day or two :shock:

So to my point
............................................

We started this thread to get you excited
We did not bother to warn you about the dangers of exposed 120VAC, 240VAC, 600VDC

Now... understand here son...
(in my best John Wayne voice)

"THIS SHIT WILL KILL YOU"

Understand?

Just like Nitric Acid will strip the meat right off your bones (as will Sodium Hydroxide... just more noticeably and faster)

10mA will make you sorry
100mA to 200mA has a good chance of killing you.

Lets do the math:

My skin - is generally about 250K ohms
Yours will be different... and yours will CHANGE as you experience stress and relaxation :idea:
So stay cool 8)

When you are working with death voltages... you stay calm
When you are swimming with sharks... you stay calm
If you trip out - (just like while driving at 150mph or tripping on acid hard...) - you can end up VERY SORRY

Or dead (which is almost always better than *very* sorry - for you - not for those who depend on you*)
anyhow

600V / 250Kohms = 2.4mA

Yea - k... no big deal right?
Uh... yea it is

Wet or broken skin... especially in the presence of voltage... can resolve to more like 1kohm :!:
(its salt meat and salt water - right? Just go measure a steak. What does it ohm out at?)

600V / 1kohm = 600mA

Thats between 6 and 3 times the legal limit!
Like... driving your car with a Blood Alcohol Level of .48 lol... your going to jail... or your going to be dead!
(0.08 is the legal limit here - no idea how stoned you can be to drive a car. I support the idea of people riding bicycles intoxicated... as if they DONT... they are just going to DRIVE... so LET THEM - SHEESH!)

...

yea - so ...

Be safe fuckers :mrgreen:

-methods
 
The squeal may well be capacitors leaking internally at higher voltage; voltage ripple; could even be a protection diode leaking under higher voltage.


I've got a DCS-55-55 I use for experiments and such (motor controller testing, etc) if you need pics of the guts/etc for anything.


BTW, the linear (heavy transformer) versions of these things are even cheaper, if you find them local (shipping is expensive). I've got a few small ones (up to about 40v/2a?) that are probably almsot as old as I am; a couple of thm still work; others need various repairs (like wiring replacment, since insulation has basically rotted off of various things like powercords, some internal wiring. old paper-covered capacitors need replacing, etc. ).
 
Thanks for the troubleshooting tip.

I will start there when I open it up later today.
(wife is still sleeping in the living room... its 4:10am... and my living room == bedroom == office at the moment :oops: )

Its like we live in a "beach garage" lol
A bungalo
A... cottage/cabin/ maybe a tree-house that fell.

...

Yea - I have friends who have a lot of the real old pull down gear.
For my purposes I limit to "Devices which are programmable and have a non-analog display"

I do appreciate the engineering in the earlier gear. Tons to learn there....

...

For today - my plan was to walk down the detailed description in the manual and start to draw up blocks of the circuit. It couldn't take more than 40 hours to reverse that system (assuming it is 2 layer - pretty certain it would be - and all parts are un-scrubed)

... ah... its almost 420 ...
I like posting at 4:19 and 30 seconds (in the morning)

Wakes people up (who are on email alert) :mrgreen:
(Perpetuate the myth)

-methods
 
methods said:
600V / 250Kohms = 2.4mA

Yea - k... no big deal right?
Uh... yea it is

Wet or broken skin... especially in the presence of voltage... can resolve to more like 1kohm :!:
(its salt meat and salt water - right? Just go measure a steak. What does it ohm out at?)

600V / 1kohm = 600mA

DANGER59.gif

We measure the impedance of people all the time in the hospital. Between a pair of needle electrodes (broken skin), it's right around 1k ohms. For unbroken skin, it varies widely depending on surface area of contact, sweat, skin type, etc. 20k - 200k is the typical range.

I can assure you that touching a 400vdc transmitter power supply will make you sorry. When I tried that, luckily all the current path was through my hand and not through my body. Still, the reflex reaction made my arm fly up and hit the wall so hard my knuckles were bleeding and got a good case of KFF.

The best approach is to never work on live equipment. If that is not possible, they make special gloves designed for working on high voltage equipment. These are really a good idea if working on something like EV battery.
 
wow... :shock:

Thanks for the real data Fechter!

...

As for hot work
I agree...
Best to be safe

The reality is - as we move into 1kV packs and 1kV chargers...
There is all sorts of troubleshooting to do
Fingers get in there
Probes probe around
...

I have traditionally avoided gloves for the fear that I would become dependent on them.. (thin gloves) and then they would puncture.

I dont use thick gloves as they are just too clumsy

So - I just treat it all as hot work and try to be SUPER careful.
Creating a path
From the hand you are using
Back to the potential... SHOULD... help

... Where... creating a path
from the OTHER hand
back to potential... lol...

Not the one we are looking for :mrgreen:

-methods
 
Thanks for the guide buddy, i bet it helps a ton of people!
 
Thanks for all the stuff you have posted Luke.
Nobody has pushed me more to take risks and catch balls in the gears that you buddy.

...

I am now sitting down to open up the 600V controller and start the procedure.
I may have lined up some side work (which may pay - so takes precedent - but today my goal is to:)

1) Open up the 600V supply and take some pictures
2) Look for any obviously blown parts, ID them, and get replacements ordered (also look at all the parts near those parts)

Lets see if we can get this thing to produce power!!!

(Updates will be in the 600V post - about 2nd or 3rd down from top)

-methods
 
P.S.
Since Luke popped up...

"I accept that I am doing dangerous work that may electrocute or kill me. Should I die or become handicapped or maimed due to this work it is no ones fault but my own. I am a qualified engineer, with 20 years in the field, with fancy degrees, and I fully understand the risks of electrocution via AC and DC. It will be a horrible, painful death - like the death we give inmates - only much slower. Nobody can sue anybody as a result of my death from my DIY hobbies. Nobody should and nobody will. My choice. My life."

Disclaimer complete.

(We once used a flame thrower to test Lukes fire-proof suit. We learned that it was indeed fire proof but it WAS NOT infrared heat proof. He experienced fire'y hell for 10 seconds or so. Before that test - he remembered to absolve those around him (me and another guy) of any guilt should his human body or mind become fubar in the experiment. ... anyway ... always remember to do that. The blood sucking lawyers are NOT OUR FRIENDS. We do not sue people. We do not sue companies. We enjoy our freedom and accept the risks associated with living life with the privilege <right> of choice.)

-methods
 
UPDATE:

I updated the 600V post
https://endless-sphere.com/forums/viewtopic.php?f=14&t=95184&p=1394100#p1394100

Got side-tracked with paying work

Wife is now looking at me with that same look... the one that means she either wants sex or entertainment...
So

Since sex is clearly the devils work... I will entertain her.
She said she either wants the electric Kayak back in the water (I am worried about the brushes... did not rinse it last time)
or
Our usual standby is to go collect treasure up the coast.

Treasure it is...
(but lets see - I think I can get one more post in real quick - maybe power up the controller uncovered and try to get electrocuted while turning the CAL dials :cry: )

-methods
 
The 600V post is getting too long...
gonna work it here

file.php


I am interested in R47 and R52
Not worried about calibration for the monitor
Not worried about output range
I want to know what this offset is... and how it affects us...

Marked Clearly.jpg

Not only are the pots marked... but the silkscreen actually lists their function as well!
(this is a good sign - it means the engineers wanted us to succeed... and not to fail)

Ok - so what the hell does it mean?

Voltage
R52 is used to adjust the offset on op amp
U5

U5
A current shunt (R91) in the output return line develops a voltage proportional to the output
current. This current information is amplified by U15 and compared to the setting of the current
limit control in the current control error amplifier U4-1. The output voltage is also monitored and
compared to the voltage control setting in the voltage error amplifier U5. The outputs of the
voltage and current error amps are OR’d through CR18 and R26 and this signal is fed into the
PWM error amplifier inverting input providing the negative feedback required to produce a
regulated output. The output voltage and current information from the current and voltage
control circuits is also fed to the front panel A1 assembly where it is displayed on the digital
voltage and current readouts.

... more on U5 not listed but worth reading - full description of the transfer function / feedback loop

Current

The
offset and gain of the current readback signal may be adjusted through holes in the cover of the
unit (see Section 4.4 Calibration for location of adjusting holes).

Oh kay....
Sigh... most importantly:

Note: Consult the factory for full calibration requirements.

OK
Before I go further I want to see if this information is available


-methods
 
OK - back on it for an hour or three.

Normally I would dilly-dally through all the learnings to see what we can see - but vacation is coming to an end and I have got to get back to the grind.

So -
To fast forward based on evidence:

1) As seen on the markings of the case... the supply is putting out a lower voltage while on the 120V setting than on the 240V setting.

2) As seen in my notes... I have confirmed that if you attach 240V to the unit while it is wired for 120V "magic smoke" comes out. I am going to speculate that a similar reverse may be true... that if you apply 120V on the 240V setting... that "other" magic smoke may have already escaped (due to the fact that this is a constant power test, so half the voltage means double the current, means smoke-smoke in a value engineered design)

3) I am going to move forward on the assumption that it is the AC input stage which is compromised... and that the later stages are fine. No idea if this will pan out as correct - but I am making the decision based on the evidence I have - and a hunch.

(I have not troubleshot many switching power supplies... )

4) I am going to now scour the data sheet for clues - component part numbers, descriptions of expected operation, etc... to "sniff around" the AC input section. If I can not narrow it down analytically I am going to test it destructively... but placing the unit back into 120V mode - and applying 240V - to detect the exact location that the magic smoke emits. From there I will back-trace out and check the health of all the components. I suspect that some semi-conductor or another is working - but in some sort of broken/burnt/partially conductive mode -... or... maybe some coils cooked together.... or... meh... who knows.

5) This supplies guts are quite different than the 60V 18A that I play with most - so it is not immediately clear that I can swap any components without SIGNIFICANT rework.

6) The procedure I would describe for someone working for me would be as follows:

a) Identify (circle) the different sections in the PCB and figure out - high level - what they are doing. Example... what is the bridge of 470ohm resistors doing in the back right corner? Looks like they are wired parallel - series... so 235ohms ... well... its a 1.7A supply (very low current) and 1.7A * 235ohms would be 400W - and those are about 5W resistors - so we can safety say that they are NOT inline with the power output. (Yea -obvious - but the sort of deduction we want to use to eliminate possibilities while guessing at what things do.

b) Assume the circuit is segregated into AC, chopping, Cleaning up DC. DO NOT ASSUME that co-location tells us anything... as the AC input is in the back left and the AC circuitry is in the forward left (along with the AC power switch etc) - There is some heavy duty AC gear in the back right - then it jumps out to wire to the front switches - so we can take a measurement there (or better yet - probe around with a scope) to guess at what each section is doing (going on the assumption that we have nothing and know nothing - where of course - we could search google for similar input stages to get an idea of how architecture is laid out in a device like this) - example being... whether it is a PFC rectifier or a McGhetto rectifier - we can guess by the year of production and complexity... like that

c) We can use the component listing to at least notate the picture as to what is happening where... like... we know where the FeedBack OpAmps are for the DC Closed loop circuitry. I would mark the board up in colors - with White for raw AC, Yellow for processed Ac, Orange for chopping, Pink for loose DC, Red for clean DC - something like that - to help get a feel for what the hell is going on.

d) I have a set of pictures which I did not post that cover some interesting bits - like rework in production, evidence of large components mounted on the under side of the PCB, and other indicators that we need to pop this thing out of the case and sniff around the bottom... where in my fantasy life... we find a big burnt trace... or a big burnt part... just hiding and waiting to be replaced... where there is evidence of the failure (some insulator shifted... or heat sink clamp came loose) and we can just magic wand the fix and be on our way.

7) Onward....


In order to properly troubleshoot a device of this complexity I will require an O-Scope. Yes... I could piss away another day off... trying to prove that I can build a nuclear weapon out of a salad bowl and some ground up aluminum cans - but its pretty pointless. A scope is an engineers eyes and ears... where a DMM is simply a finger. GOTTA HAVE A SCOPE if you want to do work like this.

Scopes
Avoid at all costs... those scopes which claim to do all you want... in a box half the size of a pack of smokes... with no external supply running off the USB. Many times the specs are hosed on devices like this. yea - one or two may be rad - but you are looking for things like this:

A) At least 2 channels. 4 are rarely used but 3 come in handy. We do a lot of relative measurements.

B) Isolated is far superior to earth grounded. We are troubleshooting an earth grounded device... so the moment you plug in the device... and then plug in your scope... and then touch that ground probe to some place in the circuit... you change the circuit* This can be proven by placing a DMM or isolated scope between the test point ground and the scope ground. If there is ANY potential there - this is evidence you are suppressing. Isolated scopes allow you to poke into sensitive balanced circuits with minimal impact.

C) Old analog stuff with dials... they are all worn out and fubar... for the most part. Go digital. Stay away from the old modular types as they tend to be very fussy. I still am fond of the 90's scopes with the green display - like a TDS. As an alternative there are great deals on newer purely digital scopes - but be ware - that you get what you pay for with a scope. Specs are hidden... and ... just because a scope is marked as 200MHZ or 2GHZ does NOT mean that you are going to be able to troubleshoot at that resolution in real time. Lots of these newer cheap scopes can only grab snapshots at this sort of resolution - where you have to capture, hold, then zoom in. Difference being that with a $20k scope you can actually watch things happen at nanosecond resolution in apparent real time - setting up triggers and sliding around thresholds sneaking up on it. ** Consider it ** Consider ebay ** Consider spending $500 on a proper scope if you want to do proper troubleshooting.

D) Probes are part of the cost. You can spend $100 to $1000 easily - on A PROBE. The probe is what determines how much impact you have on the circuit under test and how fast of a noise response you can see. If you are looking for 200MHZ noise with a 100MHZ probe... eh... you aint going to see it brah. K? So - we are looking at the higher end probes - at least one - plan on dropping some coin. With the isolated scopes you get what you get... they are often a mated pair ... but for higher end, older scopes - it is all about the probe. Consider also the voltage range you will be working across. You want a probe capable of running in 1X or 10X mode - this will help.

E) Exporting data - the biggest drawback of the older scopes is that you have to take screenshots with your phone. There is a 10 year window of scopes that have printers built in, floppy disks, Flash cards, you name it. All of these are shit - they all suck. In my opinion you have two types of scopes: PRE data accessible and POST data accessible. Post data accessible means you just poke a USB stick in there and you can get Pictures and PointSpreads (CSV or Tab data packs).

F) For ebike type stuff - or anything 3 phase - I strongly prefer an isolated scope. Relative measurements are interesting and you cant take them with a common ground. YES - NORMAL SCOPES ARE NOT ONLY COMMON GROUND - ITS EARTH GROUND - SO BE WARE.

What was I doing?
Oh yea... learning about power supplies.

... Yea... yea... you may not want to wade thru my utterances... but listen here:

I have a kid
He will one day walk a path
I hope that there are people who will clear the bushes for him - as some have cleared the bushes for me. Engineering is a HUGE field... and to have it dumbed down by someone like me is an asset. Some nose in the air engineers may not appreciate it.... but I know... that if you are on the cusp between Engineer and Tinkerer... it helps to have something to take your relative measure against.

I share what I have found to be most useful as a mixed hobbyist and professional - where my professional tools are out of our reach ($20k to $50k easy) and the hobby tools will just waste your time (anything under say... $400). Many people are turned off of math and engineering by bad experiences.

Example:
Try to teach someone to use a non-auto-ranging MultiMeter
Sigh... what a frocking nightmare of bad measurements

While teaching a man to fish -
Give him a good pole, good line, good knots, good hook, fresh bait, and ... take him to a good spot at a good time. Let him (or her) taste success... then let them go try on their own.

Allow them to come back with no fish - and show them the magic again.

Repeat until they show you where to fish.

Thats my plan... now who is going to show me how to fish?

-methods

P.S. Tip
Shore fisherman pulled out a whopper at my beach the other day. Had nothing but a short pole, some heavy test, and a shiny lure with a big frigging hook. Landed a halibut that would feed 4. Most guys are out there with multiple log poles (to cast past the break), pole holders, waders, complex jigs with 18 hooks on them... ... This guy was traveling light and carrying dinner.

Looked like this:

krocodile-spoon-%281%29.jpg


Only larger, heavier, more squared off - single big hook (1"), two tone blue/silver - good heavy lure - easy to wing out 30 yards - very simple setup. My favorite for lake/river fishing - now I will try it in the ocean.
 
Procedure - powering up the scope for a few measurements
(Which I cant take because my Fluke is with Calfee and my scope - is on ebay)

... but we can go thru the motions anyway ...

1) Good lighting and a clear workspace

... It has become popular (or always been popular) for some engineers to trash their work space with pile upon piles of old project detritus. This is some sort of patina - apparently some proof of past battles. Yea - this is cool - but make that a show piece. Do your actual work on a CLEAR BENCH. Use methodologies like Sigma to clear everything away except for that which you need - FOR THIS PROJECT.

I have a clear bench right now.
It has nothing on it but a soldering iron
Keep the clutter out of the way - its a dangerous distraction and it ... is just a mess.

Sparkles are what happen -
When working on life equipment -
On a bench that is covered in shit*

Electrocution is what happens as well... when you have random bits of metallic and grounded goods around your elbows... and you are touching 600V stuff. KEEP IT CLEAR - respect grounding (not for ESD - but for death paths).

2) Make sure it is your bench and that nobody is going to walk up and do something stupid like toss an ESD bag onto your live circuit. IF (and thats a BIG IF) you choose to use signage... KEEP THE SIGNAGE RELEVANT.

DANGER LIVE VOLTAGE
Signage that is up... where there is no live circuit... is actually MORE DANGEROUS...
Than a live circuit with no signage

This is because - it breeds... the wrong sort of culture.

If you run a blinking orange light and run a big sign (that you set next to your desk) make people respect that sign.
You respect the sign as well by putting it away when the circuit is safe.

We all have to use the can or go out to lunch while a hot test is running. Develop a culture where people are aware of danger and act accordingly. Isolate your "messy areas" from your "High Voltage Working Areas"... make it visual and obvious...

You may have a row of desks or benches where engineers are ... "developing their patina"...
Great

The next row over should be squared away, clutter free, running some sort of sigma, - a place for dangerous and serious work to get done.

Keep the interns, janitors, sales guys, and software folks SCARED of this area. If - those who are not qualified to work on deadly things get too comfortable around your "Safe work area" - give them a show from time to time...

BLOW off a capacitor
Make some big sparks
Yelp really loud and announce that you got bit
...

Let them know that this is the real deal over here
We are playing a game of operator that will LEAVE YOU DEAD

...

Serious bro... this shit will frost your nuts for the last time... so ...
Develop your personal work space and ensure that others respect it*

(at home - make sure the kids and wife know - that ANY circuit on THIS bench is to be considered HOT at ALL TIMES)

Like that.

... ok... time to plug it in
Swapping to the 120V single phase
Wiring in a new plug
Probing around with my $35 AutoZone DMM that sure as shit will tell me NOTHING - LOL

-methods
 
Start by searching for Sorensen
(We always dig before we tear down...)
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Similar architecture but with modern parts
Troubleshooting
https://www.youtube.com/watch?v=OMRwFnNHmk8


Ok - searching that found this:
Raytheon/Sorensen/Xantrex - (Additional Key words - how would we know Xantrex ~= Sorensen)

Gets us this:
https://www.youtube.com/watch?v=27c4RTntAPw
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From our old friend...
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TearDown.jpg
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This is a key concept:

Rarely will we find the exact tutorial, for the exact hardware we have. Instead - what we want to do - is find something similar that will bound the problem for us. Example below:
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TearDown2.jpg
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Above he is spoon feeding us many useful things:

1) component identification
2) overall function of the circuit

...

Before that he explained that the right side... is effectively taking Mains and turning it into HVDC... then the rest of the circuit is a DC-DC converter (confuses me - but ok - he has taken apart more than I have - so lets figure it out)

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TearDown3.jpg
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Very clever way to set up a thermo couple !
Never thought of that. If the terminal is highly conductive than it will translate the temperature well.
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I set up an RTD the other day for my salt water tank by using a straw filled with epoxy. No mounting requirement there. I found it to be amazingly accurate across a stupid range. (by hobby standards - not aerospace). I calibrated it with an ice-cube tray that was half-frozen (so i mashed it up). Obviously at the other end you use simmering water. (NOTE- freezers must drop well below freezing so never cal against that - you must have some form of water in transition to cal)

Three points of CAL: Ice Water, your mouth (or butt), boiling water.
(Be sure to check two peoples mouths/butts - and dont ever check butt then mouth - trust me on that...)
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And now for some money shots...

TearDown4.jpg
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Anyone who does not love this guy is a hater thru and thru... So what if he is quirky and not always spot on - AT LEAST HE IS DOING IT.

I reserve my lowest respect positions for:
1) People who do nothing and criticize those who do.
2) People who were abused, refuse to acknowledge it, then go out and abuse others - especially with the power of law or money
3) Violent clowns

There are more... but those are some top three
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