Ultra 350w ATX Power Supply

[bigbeark]

I have 2 of these. This one had no Standby Power when measured. For a cheap PSU this has a great many components on the PCB. Many tiny resistors etc. in the secondary.

I found one domed cap in the secondary and the PS-ON green wire looks to be damaged by arcing where it enters the PCB.

The third picture shows the arcing on the green PS-ON wire, and the second last shows the doming on the capacitor between the two toroids.


Comments and Suggestions welcome.

[stj]

Re: Ultra 350w ATX Power Supply

not arc'ing, that's conductive glue - glue that got old and went very dark and then burns
you need to chip off all brown glue - then do the caps

[momaka]

Re: Ultra 350w ATX Power Supply

Looks like a Young-Year PSU (and probably is, since Ultra did use that OEM for some of their modular series, if I remember.) Though, it could also be (and likely is) a WinTech, judging by the "WIN" writing on the transformers

Anyways, I don't see any arcing, and there really wouldn't be a high enough voltage anywhere on the secondary side to cause arcing. But I do see traces of the tan glue, like stj suggested, that goes brown and conductive over time.

Before anything, check the fuse on the primary side and the green NTC thermistor next to the big yellow caps on the primary side - both should show very low resistance (the NTC might measure around 5-8 Ohms or less, depending on what it is.) If these do test good as stated, replace the caps on the output of the 5VSB circuit. I see a lot of yellow "GL" -branded caps. All of those are utter garbage and can be failed without showing any signs... though I do see one bad cap in there already (looks like either the 3.3V rail.)

If the 5VSB still doesn't come up after that, the 5VSB circuit may need some troubleshooting. It's a 2-transistor 5VSB circuit again, probably very similar to the one in your Thermaltake TR-430 PSUs, so you can use the schematic I provided there. I also have an Apevia ATX-AS520W PSU that is somewhat similar to this one and also has a 2-transistor 5VSB design. Looking at that thread, though, seems I never posted the 5VSB schematic I made for it... but it's not that much more different than the ThermalTake TR-430 one. Really, main differences are that on my Apevia, the 2-transistor 5VSB does not have a "critical" cap on the primary side and uses a BJT for the main switch (2SC5353 in TO-220 case.) Also, there's a 0.47 Ohm 2-Watt resistor on mine between the +320 DC bus and the 5VSB primary-side transformer. So if no 5VSB on yours after running the checks above, see if the primary-side attached transistor for the 5VSB (the 2SC5353 or similar) is still good, along with checking its Emitter-resistor to primary ground and checking if there is a 0.47 Ohm or similar resistor between +320 DC bus. Any of these resistors and the BJT could be open-circuited if the 5VSB output caps went bad.

All in all, your Ultra PSU posted above uses pretty basic designs for both the 5VSB and the main PS, so troubleshooting that one shouldn't be too difficult if you don't mind doing some soldering too (well, it may not be needed if the 5VSB output caps is all that is wrong.)