Bad caps or bad power supply or something else?

BBCMember · 11-03-2009, 08:34 PM

A client of mine went away for a week and his computer was off. Then, when he came back and attempted to boot up, it powered up for about 2 seconds, and then shut off immediately after that. Then he tried booting up again right after, and it wouldn't do anything...no power, no nothing. So he waited a few minutes, tried it again, and it did the same thing as before...powered up for a couple of seconds and then nothing.

So, he tried the following that people have suggested to do with this specific system (which is a Dell Precision 470 running XP Pro SP3, 3.40GHz cpu, 4 GB of RAM, 250GB HD) when having this issue:

1. Unplugged on usb devices
2. Cleaned out tower of dust with air can
3. Changed the CMOS battery (changed it within 2 or 3 seconds) - BTW, nothing was reset jumper-wise when he changed the battery...could that have anything to do with this issue? Do we need to reset the bios or load default settings?

None of the above helped. So he ordered a new PSU, which I have just finished installing. Now it powers up (but the PSU is noiser than the original one), but is hanging at the Windows bootup screen (where the blue dots under the word "Windows" are going back and forth).

I looked at the mobo and noticed that he might have some bad caps. I've attached pics for you guys to look at. Are those bad?

Nothing was changed software or driver wise, so I really don't think it's software, driver, or OS related. It seems hardware related.

Also, do caps on a mobo all of a sudden go bad or is it gradual? Since there seem to be so many potential bad caps (judging by all of the caps that have a brown solution that came out of them that is sitting on top of them), I don't know whether that happened all of a sudden or over time. I did read that bad caps do cause a system to not boot up fully.

Please advise ASAP. Thanks.

Rocketmech · 11-03-2009, 08:48 PM

All the pics show leaking blown caps. Since the board will power on and Windows tries to load, there is a very good chance replacing the caps will repair the board. Thats what I would do. The other choice is to replace the board.

Ol'Tunzafun · 11-03-2009, 09:08 PM

Yeah, those caps are bad, and the board is behaving the way you would expect it to if the caps were bad. They do go gradually, but those are in an advanced stage. Try to find another motherboard with the same chipset, so that Windows will boot successfully when it is replaced. You'll have to install a few new drivers, but it saves quite a bit of time doing it like that.

BBCMember · 11-03-2009, 09:15 PM

OK. Thanks. So are you saying it's definitely the bad caps/mobo? Could it possibly be anything else? Do bad caps happen instantly or over time?

How would one replace the caps? Is it hard? Have a link?

What are the chances of the PSU and the mobo going at the same time?

BBCMember · 11-03-2009, 09:21 PM

OK. Thanks, Ol'Tunzafun. Do you have any sources you would recommend where we could buy one at a decent price?

I typed in the service tag in the Dell replacement parts site and came up with no fewer than 4 motherboards, all of which are over $300. Not sure which one is the one we need, as I can't find the part number of the mobo on the mobo that we have now.

Do you think it's worth it replacing the bad caps, or is it better/easier/more secure to just buy a new mobo? If you would suggest replacing them, how to you replace them? Thanks.

Rocketmech · 11-03-2009, 10:02 PM

Recapping your motherboard

You can sometimes get a TV repair shop to replace the caps if your not setup to do it. Its not hard to do yourself, but you will need an iron that will go to 850F.

Ebay or Google for an exact Dell replacement. Tunz was referring to a 3rd party board with the same chipset, which for the Dell Precision 470 would be a Intel E7525 that supports Xeon processors. The Service Tag should be able to confirm that.

The chances that other components are bad are very possible. You need to check everything.

Rocketmech · 11-03-2009, 10:05 PM

BTW, the "client" may have a chance with Dell replacing the board if there is a known issue with bad caps with that model. It's worth a check.

Rocketmech · 11-03-2009, 10:19 PM

Here's an idea of the cost for new caps.

You can buy Panasonic's from Digikey or Nichicon's from Mouser here in the US.

Ol'Tunzafun · 11-04-2009, 12:23 AM

It appears that the third party boards are not going to bolt up in that case, so you may have to bite the bullet and buy a new Dell board. I off-handedly suggested a third party item because I am not comfortable replacing a defective board with an identical board. That seems like asking for trouble, but the options are few.
If you are going to try to replace those caps, I would recommend investing in a Weller WES51 soldering station. It'll make the job a lot easier and if it doesn't work out, you will at least be left with a first class tool that will serve you well for many years. (It will do 850ºF)
http://www.eham.net/reviews/detail/2671
I have a box full of cheaper ones that I'm sorry I bought.

BBCMember · 11-04-2009, 02:02 PM

OK. Thanks. Not sure if I want to chance replacing caps for a client when I haven't done it before. And since there is a chance that other components could be bad as well, that's not good.

We've been getting "keyboard failure" every now and then, and at one point, the keyboard would not allow us to type. So we couldn't type in the admin password to get into safe mode, even though we were able to choose safe mode with the keyboard when booting up. We rebooted and it did work, but of course it hanged trying to fully boot into safe mode. The fact that this happened, does that imply that another component on the mobo is failing?

Thanks for letting me know that 3rd party boards won't work with that case. I'll try calling Dell again. When talking to Dell yesterday, the rep said that there was only one board that came up for my client's service tag, even though 4 came up for us when we did a search. We did not know which one to choose, but he said he only came up with one, and that it would work. We asked him which chipset the board he saw had, and he put us on hold. Eventually, he disconnected the call. I guess he was hoping we would give up and hang up.

The mobos that we see listed on the site when we type in his service tag, will all of them work, or will we have to choose the right one? I know when I have fixed Dell's in the past, even though I type in the service tag for that computer, it sometimes lists 10 different drivers for one component, and of course only one of those is the right one. So, I'm not sure if Dell does the same thing with replacement parts.

Have you guys ever had a Dell rep be mistaken about a part? Is it possible that they would suggest a board that did not have the same chipset? I'm not sure how much the Dell reps in India know about replacing a mobo on a system. Thoughts?

BBCMember · 11-04-2009, 03:07 PM

Just gave Dell a call and they said this is the mobo to get, but there are no Tech Specs to confirm.

Part# KG051
http://accessories.us.dell.com/sna/p...KG051#Overview

Any way to confirm that it has the same chipset? It's actually a different one than the one that the Dell rep suggested yesterday, which is why I'd like to confirm before my client buys it.

Ol'Tunzafun · 11-04-2009, 05:01 PM

It will be the same chipset.
Dell has been replacing these with boards outftted with solid capacitors. Hopefully that is what you will receive.
I offer the following link only as a cross reference. (Dell part # KG051 = E7525 chipset)
http://www.blueskyave.com/servlet/th...erboard/Detail

BBCMember · 11-04-2009, 05:39 PM

Perfect. Thanks.

BBCMember · 11-08-2009, 01:50 AM

Just wanted to let you guys know that the motherboard that Dell suggested (the second time) was the exact same motherboard and installed without a hitch! Did not need to reinstall even one driver. Smooth sailing all the way. And that was the problem...bad caps. Thanks!

We took a look at his other computer, which is the exact same system, and surprise, surprise...it has no fewer than 16 bad caps, even though it seems to be working fine. I told him that I would HIGHLY suggest he replace that board as well, as it could go at any time, and you never know how much longer Dell will decide to carry that board. He said he will definitely consider it. The only hesitancy he has about doing that, is that he was thinking of eventually replacing both systems since they are both 5 years old, and the new software that's out that he may use in the future for his work will require higher powered systems.

Thanks again!

Rocketmech · 11-08-2009, 11:13 AM

Well done. After 5 yrs up time it would be prudent to upgrade soon.