HP A265C P4SD-LA Power Issues

[jedwar10]

I have just received this HP A265C PC that will not power on at all. It appears to use an ASUS board labeled P4SD-LA. I noticed that 6 of the 7 1800uF 6.3v caps next to the processor were bulging and leaking. I have since replaced all 7 capacitors but the board will still not POST or even power up. Any suggestions would be appreciated.

[lucky13]

Re: HP A265C P4SD-LA Power Issues

Have you tried a known good power supply?

I presume you have checked for burnt MOSFETs around those bulged caps?

[Toasty]

Re: HP A265C P4SD-LA Power Issues

Caps installed correctly? ASUS is notorious for silk screening board cap position (+) in white, where typically it's (-) on others and most electronics.

What is Brand & Model of PSU? Have you checked it for same cap problem?

Had similar unit 2 weeks ago with malfunctioning Bestec PSU.

Toast

[ratdude747]

Re: HP A265C P4SD-LA Power Issues

did you do ALL bad-brand caps?

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

Current Power Supply is a HiPro 300W. I have tried multiple 300+ power supplies. Yes I replaced all of the same series of caps. Any caps that matched the bad ones were replaced. As for the polarity I replaced the caps with the exact same series of Rubycon MCZ's and aligned them the same way as the originals. I tested the mosfets on board as best I can but have not tried to remove them. Any better way to test the mosfets than with an Ohm meter?

[Toasty]

Re: HP A265C P4SD-LA Power Issues

The PSU is not starting either, correct?

What was original PSU brand & model?

Testing MOSFET's on board is difficult as there are low impedance connections to them and readings may show shorted when actually they're not. Do any of them look overheated or discolored? Any with chunks blown out or cracked plastic?

If you hook up the PSU to the mobo, then plug in the PSU and switch it on (if it has one), does the +5VSB (purple) appear on the mobo connector?

You may also want to investigate the (4) 16v caps nearby the others you replaced. If they are Chemicon KZG's or the OST brand, they are suspect as they'll fail without bloating.

Hope this helps!

Toast

[ratdude747]

Re: HP A265C P4SD-LA Power Issues

could you give us a dose of pics? that would help a lot.

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

The original power supply is a hipro model HP-D2537F3R. I haven't opened it since I am using 2 other power supplies to test it. I have attached the pics requested the 4 cpas not replaced are green KZE 16V 1200uF. I have some 16V 1500uF caps (rubycon) that I believe will work there size wize. The MOSFET's look clean no blow outs or anything like that. Other Ideas??

[Toasty]

Re: HP A265C P4SD-LA Power Issues

Thanks for the pics. Nothing looks out of place. I think the PSU is a Bestec in Hipro clothing. I'd like to see when you pop it open.

Again-
The PSU is not starting either, correct?

If you hook up the PSU to the mobo, then plug in the PSU and switch it on (if it has one), does the +5VSB (purple) appear on the mobo connector?

Toast

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

Not quite following you toasty. The power supply has no switch on the back, and I'm not sure how to check the purple 5v line while it is plugged into the motherboard. When I hookup a 500W Coolmax in it's place and try to power it on the CPU cooler spins for half a second. With the original P/S it doesn't even attempt to spin. I have a power supply tester and when I test it, the P/S spins up just fine and shows the same lights as any other P/S I've tested with it.
Thanks Again.

[Toasty]

Re: HP A265C P4SD-LA Power Issues

>>and I'm not sure how to check the purple 5v line while it is plugged into the motherboard.<<
DMM?

I'm trying to figure if the mobo is killing the +5VSB line when you connect it. If it is, then likely the mobo is done.

Using the known good PSU -
Pull the CPU, memory, and video card (if one) and try powering it up then. You should get a lot of beeps from the board. If you're not, my money's on it being dead.

You are discharging the PSU before you mess with anything on the board, correct?

Toast

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

OK a little farther along here.

I plugged the powersupply into the motherboard and tested the purple line for 5v (from the bottom of the board) and it is there.

I also tried taking all of the components off the board and powering it up but it still does nothing. I dont get any beeps and the power supply fan doesn't spin up.

I also tried this method with other boards that I have in my office and they don't do anything either without a CPU.

Yes I am discharging the PowerSupply & Motherboard before attempting any changes or repairs.

I also am attaching some pics of the inside of the HiPro 300W Power Supply. 2 of the teapos are raised just slightly but none of them have vented.

Other thoughts? Thanks again!

[370forlife]

Re: HP A265C P4SD-LA Power Issues

Hipro, ahh yes. Looks decent on the inside (except for that triple group regulation on the secondary). You may want to check the voltage coming from that purple wire. It should be not much more than 5.00v. Too high could cause the southbridge to fry. Try with just the cpu in, and it should at least give a no (or bad,) ram beep code, if it even has a speaker on the motherboard.

[Toasty]

Re: HP A265C P4SD-LA Power Issues

>>I dont get any beeps...<<
Okay. I thought they would at least beep for no CPU...? Speaker connected or onboard?

You don't have to go to bottom of board for voltages. When the mobo power plug (20/24 pin) from PSU is connected, just insert your Black DMM probe into top along side of a black wire. Or, Black to any of the other peripheral connectors black wire. Red DMM probe to any one you want to check.

Also, double check (magnifying glass) your solder job on those caps you replaced. Make sure there are no bridges or "hairs" and that they are all shiny in appearance.

PSU actually looks decent. Complete input filters and a bridge.

The PSU not powering up tells me there is something wrong on the board or at least an overload. You said the 500w unit at least spun the CPU fan. That kind of points to an overload.

Perhaps replacing those KZE's may resolve it.

Toast

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

The KZE's are 16v 2200uF I only have I believe 16v 1500uF in stock. would these work or do I need to order some more caps?

Thanks,
Jason

[Toasty]

Re: HP A265C P4SD-LA Power Issues

You could use them, at least in an interim capacity. Not knowing if they are the problem nor having an ESR meter to test them makes this entire process a crap shoot at best.

- You could replace them and still not have it post.
- You may never find the source of the problem.
- You could recap the entire board and still not get it working.

See Big Pope's site on this thread. It's an entire recap of that board including the 3 yellow Fujitsu polymers as you have. If you register, you can see all the pics (tons!).
http://www.capsmod.net/forum/viewthr...&extra=&page=1

As he says in there, and many have said here many times, "If your motherboard fails to post before recapping, it means there is no guarantee to post after recapping."

IMO -If it were my system that I used every day and I needed to be "right", I'd recap it in a heartbeat. But, since you received this and have no "history" with it, proceed with caution and be prepared to be disappointed.

Toast

[jedwar10]

Re: HP A265C P4SD-LA Power Issues

OK I finally figured this thing out.

After talking with Toasty a few times he said something about a short, so I looked over the board again and found that my solder removal tool had barfed on the pins under the PCI slot.

After removing the extra solder and testing with a known good PSU it finally posted. I then tried it with the original HiPro PSU and nothing happened. After replacing the 2 caps mentioned before that were just slightly raised, but not vented, in the Original PSU the computer posted again.

I have now reassembled the entire PC and it is running updates right now.

Huge thanks to Toasty & a new lesson learned. A PSU tester is not the final test of a good PSU.

[Toasty]

Re: HP A265C P4SD-LA Power Issues

Excellent!! I was concerned there was a more serious issue with that board. Whew!

Do yourself a favor and either a) finish the recap of that PSU or b) get a new one.

A problem in the brand and series of the 2 caps you replaced (they all look to be from the same brand) indicates that you'll have more failures down the road. Save yourself the headache(s).


Toast