A mini re-capping guide

psiu · Post by **psiu** » Sun Oct 11, 2009 2:23 pm

Intro:
This summer I ended up re-doing our HTPC, I had an extra AMD BE-2300 (45W) laying around, so I figured I could make the machine into an HD capable HTPC with our HDTV. I found an Asus AM2 motherboard on ebay for under $30 shipped, but when it arrived, I found that the capacitors right at the main-ATX power plug and RAM slots were badly bulging. I had looked into re-capping before but never had the time or inclination to do it--being a construction worker in MI this summer meant I had plenty of free time

I picked up a few affordable tools and I ended up successfully fixing it, and it is now purring away nicely in our living room. I thought I was done with that until coming upon a thread here in the forums. Forum member/moderator NeilBlanchard had a board that he was done with due to bulging blown capacitors.

I ended up PM'ing Neil a couple weeks ago, and so here we go:

Our patient:
It's an Asus A7N8X Deluxe rev 2 board. SATA, dual-NIC, Firewire, and Soundstorm audio. I have DDR, AGP cards, and a trio of socket-A CPU's available, so why not give it a shot?

Scalpel please:
I had a 15/30W soldering iron--it's not really enough for this so over the summer I picked up the 40W and the 45W desoldering iron. I have some solder with flux and some really fine stuff without. Some various snips and pokey implements.

Your nurse:
She really wanted to help. Chased her away when I fired up the irons.

The operation:
No pics during this...the one I did over the summer was easier, was able to vaccum out the holes. This one had much smaller ones, I ended up going with the "melting the solder from one side and pushing the new cap through" technique (not particularly recommended). I really need to add a stainless steel pick to my tool set for cases like this (the solder won't stick to it), as well as a chisel point for the iron.

Post-op:
Gave it a run over night with one stick of memory in, no problems. Threw in another one and it went overnight also with no problems in dual-channel mode.

Put on the Swiftech heatsinks *grunts* and went dual-channel:

Conclusion and more information:
The tools and supplies needed for this cost under $50 to start--and the caps needed for re-capping a board are quite affordable. The iron shouldn't be more than $10-15, same with the solder-removing iron (or you could try just the bulb, or desoldering wick, the pump isn't recommended for this though I have one also). Solder is pretty cheap and a little spool or tube lasts a long time. I have some rosin flux and cleaner also.

I bought the caps both times from the CapKing. To fix this board I bought a couple extra and picked the high end ones, it was still only $6. He has some good instructions there, also has a link to some very thorough instructions here. I also spoke with him via email, I can definitely recommend him as a source for caps. Another site that I had looked at previously and is very informative is BadCaps.net, though I haven't had the opportunity of purchasing from him yet.

So if you are ready to toss a board, stop and give it a shot--if you already have some of the supplies it's very affordable and could save having to get all new parts, reinstall OS, etc.

Final verdict:
Recap your board, and you feel like a complete bad-ass

colm · Post by **colm** » Sun Oct 11, 2009 2:58 pm

I may do that just for higher grade stuff. I have nit had a bulging cap since an athlon 900 in the year 2000, reverse cooling and micron changes, it seems to be headed for may more hours than I racked up already. I found they do not like heat from heatsink fans. I am sure they try to gather and recycle through themself more than heat. Reverse cooling proved it to me.

thanks for link to the cap site, I didn't know you could buy them.

Now where to get those sealed fluid filled ball bearing I found in a nidec recently...

Mr Evil · Post by **Mr Evil** » Sun Oct 11, 2009 3:49 pm

Makes sure you use capacitors with a low ESR (Equivalent Series Resistance). If they don't have low ESR, the very high peak currents in the circuit will cause them to heat up, shortening their lifespan.

Post by **NeilBlanchard** » Sun Oct 11, 2009 4:05 pm

Hey, that motherboard looks very familiar...

Good job on the fix, and the write up!

psiu · Post by **psiu** » Sun Oct 11, 2009 4:48 pm

Mr Evil wrote:Makes sure you use capacitors with a low ESR (Equivalent Series Resistance). If they don't have low ESR, the very high peak currents in the circuit will cause them to heat up, shortening their lifespan.

Yep--these were Rubycon MBZ 6.3V 3300uF caps with "ultra-low ESR for VRM" according to the spec sheet.

bonestonne · Post by **bonestonne** » Sun Oct 11, 2009 6:25 pm

i've done this in LCD monitors, pretty simple...i didn't use all the extra bits though, just a soldering iron, and actually regular caps pulled from dead electronics (as long as they were good replacements).

i just used a normal radio shack 15W iron for it though...it did just fine. used a pair of pliers to pull one lead out at a time, and then putting the new one is was same principal but backwards.

could have fixed a P35 board from the dump doing that, but when i saw a choke was ripped off, and pins in the socket were bent, i stopped trying to pull it out, there's no return from that.

Mr Evil · Post by **Mr Evil** » Mon Oct 12, 2009 7:46 am

bonestonne wrote:i've done this in LCD monitors...

Electrolytic capacitors are the number one cause of failure of any electronic equipment that I have come across. They are fortunately easy to replace, as you have found, however a lot of equipment, including monitors, has potentially hazardous voltages inside even after being turned off, so nobody should attempt such a repair unless qualified.

AuraAllan · Post by **AuraAllan** » Mon Oct 12, 2009 8:40 am

Great and interesting write up psiu.