Dell GX280 \ LiteOn PS-5161-7DS question

[budm]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Start up caps are also part of the cap kit that should be replace at the same time.

[Agent24]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Wow, that 10uF cap has nearly 40 Ohms ESR!

The again, these PSUs probably run quite hot. No surprise if even Japanese caps get cooked in there (granted, it will probably take them much longer).

Oh, it gets hot alright... The fan speed is also stupidly low. These PCs look like they were designed for a certain size and noise level, with total disregard for _anything_ else. If I keep it I might mod the PSU fan to run at full speed.

I guess the small caps even in these regular PC PSUs should never be underestimated. Learning something new everyday. Good job on the repair, by the way .

I found the clue here: http://www.repairfaq.org/sam/smpsfaq.htm#smpsuc3842d Problem is, it's buried down the bottom of the page - they should have included it as part of the 'power cycling troubleshooting' section at the top!

Start up caps are also part of the cap kit that should be replace at the same time.

I didn't think of it before because the symptoms were rather odd.

It *did* start when connected to the PC, then it would run for a bit, then it would start power cycling.

With a dead startup cap I expected it would never start at all, and if it was some big problem I would expect it to power cycle straight away.

That's why I thought (maybe badly) it might be something in the monitoring circuitry.

[budm]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Put that cap on ESR meter while heating up with hair dryer to see if the ESR will drop if the cap is not too far gone, I use hair dryer alot to locate bad caps problem.

[Agent24]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Put that cap on ESR meter while heating up with hair dryer to see if the ESR will drop if the cap is not too far gone, I use hair dryer alot to locate bad caps problem.

Yeah, it did. I also made a video for fun: https://www.youtube.com/watch?v=yFUu3fopfls

[BigTroll]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

wow nice video, probably explains why my old macintosh lc power supply fires up if i put a box heater in front of it.

[momaka]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Yeah, it did. I also made a video for fun: https://www.youtube.com/watch?v=yFUu3fopfls

Nice video! This should be made into a sticky. Pretty cool.

[Agent24]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Glad you like it. I would have liked to make a better one but my camera is too old (limits to 30 seconds), plus I think a thermocouple could have been useful.

[gcharal]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Thank you all for your information.
I manage to repair my psu with your help.
I wanted to add that in secondary section of my psu there were many cracked joins.

[sam_sam_sam]

Re: Dell GX280 \ LiteOn PS-5161-7DS question

Thanks, might have a look, at least it may clear up how the PWR_OK signal is supposed to work on this PSU...

One thing I can tell you is that HP switching power supply can not be run very long with out a motherboard because the power supply will lock up in this mode of operation