mwkeefer
1 MW
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Repairing Meanwell Power Supplies
- Thread starter heathyoung
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geofft
1 kW
Postby marcexec » Sun Jan 11, 2015 8:23 pm
Cool, thanks for sharing.
I'll have another go at the 2 USP-500s I broke at some point
....they look quite different beasts from the S and SP series stuff that many of us seem to delight in exploding.
Did you manage to find a circuit diagram for them?
marcexec
1 kW
geofft said:Postby marcexec » Sun Jan 11, 2015 8:23 pm
Cool, thanks for sharing.
I'll have another go at the 2 USP-500s I broke at some point
....they look quite different beasts from the S and SP series stuff that many of us seem to delight in exploding.
Did you manage to find a circuit diagram for them?
sorry, nothing that is beyond http://www.meanwell.com/search/USP-500/USP-500-spec.pdf
Have two new ones and a Mini Meanwell Limiter (on stripboard) working just fine, focussing on getting the bike on the road...
geofft
1 kW
Just had another Q3/4 go down on one of these S-400-48 units, this time in normal operation unlike my previous fail in this thread.
The problem was low o/p, I'd set the current limit on this supply to around 6 amps (at 48v) but it wouldn't o/p above 1.5 amps. The fail mode was partial short c-e, these transistors seem to be a bit of a weak point on these supplies.
The problem was low o/p, I'd set the current limit on this supply to around 6 amps (at 48v) but it wouldn't o/p above 1.5 amps. The fail mode was partial short c-e, these transistors seem to be a bit of a weak point on these supplies.
What exactly happened just before this behavior started?
So it was already broken when you got it?
If not, then what steps exactly did you do before it failed?
If not, then what steps exactly did you do before it failed?
If you can find out what steps were done just before it failed, it would help in troubleshooting it. Different areas might be damaged based on that.
We already know it's not the input fuse because the light comes on, and most likely all or most of the input side of it works, since it gets that far.
We already know it's not the input fuse because the light comes on, and most likely all or most of the input side of it works, since it gets that far.
Here are photos of the inside. Looking closer it is clearly the capacitors and the diodes got burn. I will find parts and replace them now. Anything else I need to check and replace? How can I test the other capacitors and diodes when they are onboard? Thanks.
parabellum
1 MW
Yeah, it is the right practice and matched if possible. Must say, I did not follow this rule in some cases and got away with. :?pplayer said:
I replaced the 4 power MOSFET and it's all good now. I had not replaced the burnt cap yet as the order still on the way, but it is still OK. The only thing is that the output voltage range when I adjusted the adjuster is 9.5v - 12.5v, comparing to the spec saying 10.8v - 13.5v. Any idea? Worth to note that as I cannot find the same MOSFET IRGP20B60PD, I replaced them by IRGP4068D which supposed to be more effective and handle higher current. Is it the reason? Any way to mod the voltage to 13.8v as I need to charge battery?
SlowCo
1 MW
Great thread so I'm subscribing.
It's hard to see clearly in the pictures. The voltage adjustment pot is typically connected to the negative output on one side. You can use an ohmmeter to test this or try to trace the copper on the board. On the OTHER side of the pot, not grounded, it will go to a fixed resistor, then to the OVP test point. Changing the fixed resistor changes the adjustment range.
Again, I can't see well enough from the pictures to be sure, but it appears to be the one circled. There is an empty spot for a resistor next to it which might be for other voltages. I can't read the numbers on the resistor circled. If we know what the value is, I can make a guess as to what value needs to go across it to get the desired output voltage.
You may also be able to simply place some resistance from the OVP point to negative output to get a higher voltage.
Again, I can't see well enough from the pictures to be sure, but it appears to be the one circled. There is an empty spot for a resistor next to it which might be for other voltages. I can't read the numbers on the resistor circled. If we know what the value is, I can make a guess as to what value needs to go across it to get the desired output voltage.
You may also be able to simply place some resistance from the OVP point to negative output to get a higher voltage.
Thanks a lot fechter for the guide. Yes the value of the resistor is too small to see even using normal magnifier. I had to use the phone and zoom in maximum to read. The label on top of R169 is 1051 or 1501 (i don't know which direction is correct). The ohmmeter said around 1.2k. Can you give a hint on the value of resistor i will need to add to produce higher voltage?
I'd guess the resistor is 1.5k. I would try placing a 10k resistor across it and see what happens to the maximum voltage. Should give you about 15v max. If you don't get the desired result, it may not be the right resistor. As mentioned before, I couldn't really trace out the circuit from the pictures.
DrkAngel
1 GW
Links to various S-series MeanWell Mods
Good pics and component locations.
Previous Wiki link no longer valid
MeanWell Mods
Good pics and component locations.
Previous Wiki link no longer valid
MeanWell Mods
