Unknown Motherboard Recapping

[stevekasian]

Re: Unknown Motherboard Recapping

This is a 3 phases VRM probably with some random not really efficient MOSFETs. This will not be able to handle a 8 cores CPU properly.

And, of course, you were correct (as y'all pretty much always are!) on the CPU - The board has a 6 core CPU on it, not an 8. My bad...

SK

[momaka]

Re: Unknown Motherboard Recapping

Now I'm wondering if I bit off more than I can chew with this soldering job. The board has no traces on the back of it connecting to the capacitor leads. And it doesn't look like any are visible on the front. So do I just solder the things in and trust that there are somehow traces imbedded between the laminates?

You'll be alright. Just make sure you have a soldering iron that is powerful enough. If it's a regular plug-in type of iron without any temperature control, make sure it is rated for at least 60 Watts and has a big, fat, chisel tip (preferably copper and well-tinned). For some boards, even 80-100 Watts might be required. That's not to say you can't use a 40W iron (it can work on some boards), but most likely you will struggle with it. And if you have one of those cheap temperature-controlled stations with 900M-type tips, forget it - these don't work worth a squat. If it's T12 or T15 tips, you'll need at least a 50W iron.

Another important item you will need is some rosin flux (regular type or RMA) - gel/paste or liquid will do just fine. Apply generously to all joints you intend to solder/desolder for better heat transfer between your iron's tip and the board's joints. It would also be helpful if you have regular 60/40 (Leaded) solder. Avoid lead-free, as some of them have a higher melting temperature and can further make the job harder (unless you have a really powerful station with T12 tips).

Last but not least, forget about desoldering braid and vacuum pumps. Just unsolder the caps by "walking" them out, using this method:
https://www.badcaps.net/forum/showpo...7&postcount=23
Then use a stainless-steel needle or cork board tack/pin to clear the solder holes (heat one side of the board with your iron while pushing through each hole on the other side with the needle/tack/pin). Don't push with the needle until the solder starts to melt, though. Otherwise, you might damage the hole/via.

[stevekasian]

Re: Unknown Motherboard Recapping

Appreciate the advice, thanks.

As for the caps, I just want to make absolute sure before I replace them (I just received them in the mail today): The originals are 6.3v, and you recommended I replace them with 2.5v rated caps. This is not an oversight, right? Don't want them to blow! Thanks.

SK

[Per Hansson]

Re: Unknown Motherboard Recapping

Yes it's fine for the capacitors around the CPU.
All they see is CPU core voltage, which is around 1v or less.

Now the input capacitors you can't do that with, but the input is 12v so you would never see 6.3v capacitors installed there anyway.
(Except on super old mainboards by todays standard, that lack the ATX "P4" power connector and are thus powered by 5v).

[stevekasian]

Re: Unknown Motherboard Recapping

Thank you!

[stevekasian]

Re: Unknown Motherboard Recapping

Finally tackled this and got'er dun today. Finished product picts included; With a disclaimer on the board work: I am obviously not a technician, and these required a LOT of heat (I bought an 80w iron with a huge chisel tip, as recommended), and the board got a little browned in the process. I think it's all or mostly just melted/burned resin though.

Anyways, gonna put the computer back together and see if she works.

Thanks again for all the help folks!
SK

[stevekasian]

Re: Unknown Motherboard Recapping

She works like a charm! The boot order got changed in the BIOS somehow, but other than that I managed to keep everything intact, including drive order and letters. :-)

Thanks again for everyone's help and input here. It was really swell of you all to help out!

[momaka]

Re: Unknown Motherboard Recapping

Congrats on the repair! Good to hear it's all working again.

With a disclaimer on the board work: I am obviously not a technician, and these required a LOT of heat (I bought an 80w iron with a huge chisel tip, as recommended), and the board got a little browned in the process. I think it's all or mostly just melted/burned resin though.

It's not that bad at all for a first recap.
Indeed these motherboards can be very tough sometimes. Yours appears to have pretty thick copper planes, so that's what probably took all the heat away from your iron. Your solder joints do look alright though with a good amount of solder, but not too much. Just be careful not to slip your iron too much in the future, as that can damage thin traces sometimes.

[stevekasian]

Re: Unknown Motherboard Recapping

...not to mention any SMDs that may get hit with the tip! (I had to heat the legs on the front side of the board a few times to get them to punch through the holes. Tricky with a really hot and large iron.)

Thanks. I've done a bunch of TVs & monitors (thanks to help received on this forum!), just never a computer mobo until now. And they are quite a bit different than your standard single layer circuit board.