dell power supply

Joined
Jun 17, 2013
Messages
258
Inspired by what Darkangel done with the meanwell units figured I'll take a stab at it, thou impatient did not want to wait for a special order, picked up a reman dell power supply, now i am no expert but I figured they can't be that different.
I uploaded several photos on a photobucket account, as they are to big to post here and I have tryed, hope the link works:
http://s1365.photobucket.com/user/2007blueprius/library/#/user/2007blueprius/library/?sort=3&page=1&_suid=137195628869106384965888994205
thanks to you tube I figured out which wire goes where thou I am at a loss as far as making those outputs adjustable.
I have 3.3v at 18A, or 5v at 22amp, I need 3.65v 10amp to charge lifepo cells, looks like a couple 2k adjustable pots would do the trick if I had a clue where to solder them, any thoughts would be much appreciated
George
 
Looks like a Pepsi commercial on your work table! :p

I'm using the Dell DPS-600PB 575Watts at 12v :)
This works well as a Power Supply for chargers.

http://www.rcgroups.com/forums/showthread.php?t=1292514

The above link covers a few Power Supplies. Maybe helpful.

Tommy L sends....
mosh.gif
 
yeah I am definately not one to mess with electronics, but right now I'll have to do, I figured out how to rewire it, I need to make those chanels adjustable, and I have no Idea what am I looking at, found this http://www.youtube.com/watch?v=rpUk9hpFQL4 for an atx, foreign language to me to begin with and I am working on a dell, bought the cheapest, little did I know it's not as common as an atx
this http://www.youtube.com/watch?v=wRZtkWEBJ28 is a good one too but again, the guy makes it sound easy guess i hace to find those datasheets for my unit first
 
Tommy L said:
Looks like a Pepsi commercial on your work table! :p

I'm using the Dell DPS-600PB 575Watts at 12v :)
This works well as a Power Supply for chargers.

http://www.rcgroups.com/forums/showthread.php?t=1292514

The above link covers a few Power Supplies. Maybe helpful.

Tommy L sends....
mosh.gif

I've used the HP proliant psu to great success. Also that link you posted rocks Tommy. Bookmarked!
 
migueralliart said:
I've used the HP proliant psu to great success. Also that link you posted rocks Tommy. Bookmarked!

Yes! Great resource! The RC guys have been doing this stuff too! :)

Tommy L sends....
mosh.gif
 
I have been tinkering with this dell power supply all day and after a valuable lesson in LEDs I pretty much got it figured out now what is a good way to step up the voltage from 3.3 to 3.65, I seen in those videos I posted here there is a 3.3v sense circuit, now I don't know much but aparently this is a regulated power supply so if the load is too much the sense circuit steps up the voltage to keep it up there, can I wire a pot on this sense circuit to trick it into thinking it needs to step up the power? I only need another .3v, that or step down the 5v, any help would be much apreciated.
the videos I seen reffered to an atx supply now I see this thing has a simmilar chip, labeled lm324n, I asume this is the brains, again I do not know much, if anybody does please point me somewhere, I can take some details pics and post them on my photobucket account if you need to see what I see
 
I checked all those rc forums but for the most part it seems they prefer server supplies and also they are shooting for a lot of power too, I just need to get .3 extra volts, and so far I have come up empty as to how to go about it, couldn't even come across a schematic,
the power supply I am working with is labeled Dell nps250kb-b, the circuit boards also mention the name newton power, some of the videos I came across speak of how well built they are and seems like everybody has an opinion thou no one knows much about them, if anything I did notice since it is regulated, for the most part they all have a feedback circuit, and modding that is how you vet variable voltage, I for one have no clue as to what am I looking at, I posted some pictures of chips I seen I recon one of them is in charge but beyond that I am clueless.
I got the unit to work as it is commonly done, I need some help upping the voltage, if I cook it, it was only $5 so if anything a good learning experience, any pointers would be much appreciated, I could not even find a schematic, that would be a start if nothing else
http://www.ti.com/lit/ds/snosc16b/snosc16b.pdf does this look like the chip I need to mess with? I honestly don't know, I did check the pins against ground, several read .1v lower than my out puts, figured a resistor on the 3.3 v circuit would make it think the power is too low and up it, but I am not that smart, and I am trying to get a degree in electronics in my spare time on these forums

thank you
 
well it looks like I am on my own here, not a position I was planning on thou I figured I would post my findings regardless if no one here knows any better maybe I can help somebody else.
I posted a couple more pics on that photobucket account if anybody cares to look http://s1365.photobucket.com/user/2007blueprius/library/#/user/2007blueprius/library/?sort=3&page=1&_suid=1372109094587011980126139416414
I believe that lm324n chip might have something to do with voltage adjustment, I could not find a schematic and atx supplyes seem to be rather different, that is my best guess.
I have wired 1 computer fan on the 3v, and 2 paralel on the 5, just for gigs, that is my dummy load for now, I think it boosted my 12v, but honestly unlike all the examples I came across so far I really don't care for the 12 v
now with the main fan unpluged I get 3.37 , 5.08 and 11.99v respectively, with the main fan on 3.7 , 5.09 and 11.96, I assume the fan is 12v and it draws enough to drop voltage a few points, anyways, I have 2 led in series between power good and ground, I am still not sure what that does nor weather that was a good Ideea, but I checked it before it got a little over 5v to ground, so my Ideea was a red led drops aprox 2 v, the green 3v, there's your 5 and it does work, no resistor/diode, I am still a bit confused about all that, I checked the voltage across power good and ground, across the diodes, and I get 3.64v, I know they can add up funny, I can look up the formulas, and I am sure it would make sense if I did that, but at the moment I am not stressing it. also I don't believe I have a 3.3v sense wire, I did not see one
now I do have an easy way out I guess, wire up a green and red led across a 5v lead and ground, it steps down voltage enough to exactly where I need it thou that was a lucky discovery not so much thought through.
as for that chip, if anybody looked at the datasheet I posted, this might make some sense
voltage readings, starting at pin #1 top left, they changed a bit by the time I wrote them all down, I am sure some of my outputs did as well, I shall doublecheck on that.
1 = .52v
2 = 11.85
3 = 11.84
if I know better I would say this is where the 12v is beeing regulated
4 = 17.24 sounds like v+
5 = 2.49
6 = .52
7 = 16.23
I would say that is simmilar to the adjustable voltage circuit I seen on some of the atx chips
8 = .5
9 = 4.95
10 = 4.94
this looks like the 5v regulating circuit
11 nothing, must be ground, I'll doublecheck
12 = 3.27
13 = 3.28
14 = .6
now from what I gathered and mind you at best this is an educated guess, this chip thakes 2 feeds from each output, which seem to be slightly less than the actual outputs, guess there are a few things along the way that cause this, and based on those puts out a very low voltage which probably controlls something, what do I know? right!
I reconed that if I were to change that output, either by the use of a pot/different resistor, either before or after the chip, that would get me my adjustable voltage and I do not need much,
if I mod it after the chip I might find myself with a snowball effect, as the voltage inceases so do my inputs and off we go again,
changing the 2 inputs to read lower than oem, might get me somewhere, would I need 2 pots per channel ( what size? ) would changing just one chanel do?
where does that 16v on the 7th leg goes I am clueless, maybe I could use that circuit to get my variable voltage and leave the 3,5,12 alone?
this is about as far as I could get by myself, I guess if I am on my own I'll take a calculated guess and run with it, at the end it was only $5.
If you know better, please pitch in before I cook this thing and nothing got acomplished, at the same time if I can pull it off not bad for a custom supply that would suit any need reman for $5
 
bit of an update I performed a test on the 12v section, see what it does, I hooked up a taillight bulb where before there was nothing on the 12v
right off the bat the 12v line I had it hooked up to dropped to 11.58v, now I don't know how many amps it was pulling did not get to check that but I assume it was a bit got hot rather hot, as for the chip the v out was rather simmilar as before, it started at about .48 climed to .53, down a bit and stabilized at about 5.2 as for the 2 v in now that is where I found it a bit odd, where under no load it was slightly below the unloaded line, it now read 11.64 and 11.65 respectively, now I noticed the voltages varied a bit depending what ground I used and how loaded it was, I wonder if against an unloaded 12v line it would measure simmilar as before, either way, I wonder if I modified the circuit to show the chip 11.64 unloaded, would my loaded voltage be any higher than before, or if anything does this chip regulate the amperage? as the output voltage varied a bit at startup, voltage on the 12v feed did not budge at all,
there is an adjustable pot nearby, it had a dab of glue on it so that it doesn't move, I tinkered with it before but it di not affect voltage at all, granted it was all unloaded, not even a dummy load on any of the circuits, wonder if it regulated current? it has to do something.
anyways back to the drawing board if you got something to say please don't be shy, I'll take a bad ideea before I do this on my own, I realy don't know much, I got the basics, I remember some princyples and formulas and I can look up what I can't remember, but at the end I really don't have much experience other than wireing.
 
If you think you have isolated a voltage control circuit, add-touch a 1K resister to neighbor resister.
If any voltage variance demonstrates, you have found a mod point.

1K ohm is relatively safe ... but keep voltmeter on output and touch into resister briefly.
 
DrkAngel said:
If you think you have isolated a voltage control circuit, add-touch a 1K resister to neighbor resister.
If any voltage variance demonstrates, you have found a mod point.

1K ohm is relatively safe ... but keep voltmeter on output and touch into resister briefly.
I honestly don't know if this is a voltage control circuit or not, I watched some of those videos that I posted, its the closest thing to it that I found, pretty hard to tell considering I am inexperienced, I have no schematics yet I am trying to reverseengineer this thing, I always wondered how you figured what to do with those meanwells
when you say add touch a 1k resister, do you mean in paralel to a neighbour resister? forgot how resistence adds up but I suppose it does not realy mater there will be a change, does 1k mean a kiloohm? I am that retarded, electronicaly speaking, I think I know some terminology but it has been a while,
As for the volt meter, I asume you mean on the wires say orange/black for 3v, and touch resister into resister, the voltmeter has nothing to do with that part.
that beeing said, by neighbouring resister, I asume you mean the closest resister to the leg of the chip, and if anything on one of the input legs.
about those, I spent some time tracking the circuits in lack of a schematic, and looks like the 3 outputs for 3, 5, 12 circuits, come toghether through a series of resisters/diodes, into pin 6 I believe it was, input 2-, if anything all my voltaves on that chip were positive, if anything there was a .01v difference between input + and _, which for the most part gave me a half volt output all combined into input 2- where there was a 2v drop gave me 16.XX volts out of it, I thake it the power supply is capable of 17v +- /34 max.
I have a feeling ( notice how confident I am ) that 16v output #2 has something to do with all the voltages, changing it would change all the others, I would hope that if I tried that 1k resister on the #2input +, would be the way to start, I honestly have no idea what to expect, nor do I have a 1k laying arround ( but I do have some scraps, may be one in there, thou I did manage to blow the fuse, it was unplugged I swear, must have touched a cap, only got shocked once couple days ago, not too bad huh!, off to wiki figure out what kind of stripes on the 1k
thanks a lot, if you see this before I do something stupid let me know if I may have the right ideea here
George
 
somebody please school me on this a bit,
from what I can tell this power supply has 2 sections an ac side and a dc side, I have identified the main transformer, but there are a few smaller coils on the dc side , they look lige they are made of 2 or more coils on a round core , almoast like a transforme but I thought a transformer only works on ac, I tracked them down and it apears my power outputs bome out of them, what are those things?
 
well I may have been looking at the wrong thing all along, I tried as suggested with the 1k resistor, it either shut it down or did nothing, there's another chip labeled 2f2 dna1002e but I can not find much on it this is about all I came up with, looks like the circuit I need to mess with but what do I know
http://www.rom.by/files/DNA1002D_DIP16_type2.GIF
 
so I gave up pn the dell, it's a shame seemed verry well built, but a rather odd model, try as I might could not get any info o it or the chips and nobody seemed to know what to do with it.
so I got an atx which has been done several times, the chip is a http://www.esthome.com/product/html/?84.html, and I found a datasheet:
View attachment datasheet.pdf now this is for an EST7502B but I believe it to be close enough.
now couple ways I seen this done :
http://www.youtube.com/watch?v=wRZtkWEBJ28 this method seems odd, I think that by disconecting the pins 1,2,3 so much for having a regulated power supply
I have marked in orange red and yellow what looks to be the feedback to the chip, in blue is pin 16 and the paths through some caps and resistors to 1, 2, 3.
feedback.jpg
now this method :
http://www.youtube.com/watch?v=rkApRg5VWnc skip to 6 min apears more interesting, I think it retains the voltage regulation, and it apears to be rather straight foreward, almoast too simple, it speaks of simply replacing the existing resistors/jumper with trim pots, my understanding is that it lies to the respective pin that it needs more or less voltage.
now these are the voltages I measured across the feedback resistors:
voltages.jpg
and from the other side:resistors.jpg
the 3.3v brown black brown 100 ohm ( I think? ) and it does not drop the voltage much across it, not enough for me to measure
5v is a jumper
12v red black red 2100, 2.1k? it drops voltage from 12 to 3.8 across it.

now all I am trying to acomplish right now is to modify one of those to get 3.65v out of I have some large lifepo4 cells to tinker with, the 3.3v output is rated at 25amp on this unit so it's more than plenty, I wonder if I replace that 100 ohm resistor with something slightly larger, so that it would make the IC think the voltage is low and compensate, and how would I go about that, I don't remember the formulas, I assume the 100k on it is neglijable and therefore there is hardly any voltage drop, I am looking for a 0.3v drop I guess to make a difference from 3.65 to 3.35 it now sits at, also if I were to try a pot, what size would I choose?

Any input much apreciated
 
so I am trying to wrap my head arround the theory, honestly I have no bussiness designing circuits, I know some basics but I believe I even had some of that mixed up.
so folowing the 12v sensing circuit, I realised that once past the 2.1k resistor the power continues through a 1k to ground, so I figured that is how they achieved 3.98v at pin 3, I figure ohm's law aplies.
12&3.jpg

same with the 3.3v difference is it returns to ground through what I believe it to be a capacitor labeled 103. I think that is there just as a buffer to smooth the voltage
View attachment 3


so here is the idea:
idea.png

I wonder if this would trick the pin one to read .3v lower than the actual voltage at the terminal therefore successfully giving me a 3.65v regulated output at up to 25 amps, if I understand this correctly that is how the 12v is acomplished, or it would be a 3.8 v terminal otherwise. Will it will very much work like the constant voltage stage of a charger, it will push whatever curent is needed to maintain voltage at 3.65v?

and here is an original pic, without my scriblingWP_20131130_004.jpg

I need some help here. I am not entirely sure weather this is the proper way to go about it nor how to go about figuring out the resistor values, probl a variant of ohms law, I want to say the curent is the same throughout the circuit if memory serves me and voltage is proportional to resistance.
off to the text books I go. IF MY THEORIES AND CONCEPTS ARE RIGHT, notice how I said IF?
attached is what I came up with, any thoughts?

well I tried the 1.1k and it did not work so much for that theory love it when it doesn't :x work, maybe that orange capacitor in series trough my math off, removed everything and the PS apears to function ok without the cap, wonder if i soldered the resistor by itself, would it work?

updare so I soldered the 1.1k resistor instead of the capacitor and sure enough it did lower the voltage at pin 1 by 0.3 v, however the output is still 3.36v, even if voltage at pin 1 is 3.06v, Y would have thought the chip would make adjustments but nope, I'm stuck, any thought here?
 

Attachments

  • V.doc
    21.5 KB · Views: 103
I pulled it off, all it took was a 20k pot, wired one of the legs to ground and the wiper to pin 16, I was able to turn it down till the 5v output became 3.65v, oddly enough the 3.3 v circuit did not change at all, must be regulated in a different way, I don't have the knowhow to figure it out.
WP_20131201_001.jpg
WP_20131201_002.jpg

so I hooked it up through a watt meter I had from HK, it is rated for 30 amps, so I am charging 4 cells at a time 80ah, expecting to see the 25 amps that the power supply was rated for but not even close.
WP_20131201_003.jpg
WP_20131201_004.jpg

I guess this is what I dont quite understand, I was expecting the power supply to maintain voltage where it was set but it does lag , considering the cells were at about 3.28v before I began, does not look too bad, but neiher is is pumping anywhere near the 25amp it is capable of, neither CC nor CV, not sure what I got here but I can charge cells individually so I am happy for now, bit dissapointed most I could get out of it was 5 amp or so, wonder if I had more cells if it would pump more amps or this is all these cells can take considering the voltage difference between them and the power supply.

maybe one of you's can explain, this does not match any of the theory I read.
 
this one is rated for 25 amp on the 5v chanel, either way it's not even close, and the apms decrease as the batteries fill up, I guess the voltage diference is not enough to push more amps, I was under the impression that whatever the PS is rated at that is what it pushes all the time, I was also under the impression that it maintains a constant voltage, it does sag instead depending on the load, in this case the batteries SOC, like I mentioned I am no expert, I am at "curious" level at best, I have been reading the theory for a few years now just recently I got into experimenting with lithium, and if anything I am seeking knowledge.
I think a normal charger may crank the voltage innitialy to supply the current, than goes into CV mode, thought this would have been CV mode right off the bat , it sags a bit and the PS should have the capability to pump it up and compensate, I guess it doesn't do a verry good job, I am ok with it for now, I am in no rush to charge these cells and having the PS set at 3.65v, if anything it will tricle charge those cells toward the end there, which I'm thinking it's fine since these are some questionable cells I am playing with, I just want to see if they will hold a charge and what I have left for capacity.
For what ita worth this PS was $15 brand new ( a used one is pretty much worthless I just didn't have one, I havent disabled any of the OVP, UVP circuits, acording to the datasheet, I had enough give for what I wanted to do, the 5v I can tune down to 3.65 and up to 6 something, I think the 12v can come down to about 7v and goes up to about 14 something, all in all quite versatile I think, can charge single lifepo3, lipo, 6v golfcart bats, rc packs for whatever use, car batteries, further more I have a -5v and a -12 v, I think they are rated at 5 amp or so, but in combination with the 12v line I can charge 24v packs or anything in between , as for the adjusting part , I was only looking for a fine tuning if anything, all in all I am pretty happy was hopping this had been done before and the forum would know more about it but overall, it was just me and youtube, maybe some of the brains can pitch in from here and I can learn somethin more, at this point I am trying to get a better understanding of what I am doing here
 
Back
Top