Replacing Motherboard Capacitors

[Galaxybr8]

Hi Everyone!!! I must say, as an electronics technician for some 25 years
Ive tried to replace capacitors on mainboards in PC's several times (Mind you I work daily with
surface mount components and the like) And have had absolutely 0 % success... Traces usually are lifted. I use a very very expensive Hakko Soldering station, solder suckers and desoldering braid and have had no success at all. Ive found that a "Dremel Tool" has produced the best results so far. I simply tape up the motherboard components with masking tape and newspaper,Take my dremel tool with the cut off disk and chop the capacitor in half, suck out the remaining electrolyte with a turkey baster and spray off the remaining electrolyte with electronics cleaner. I whittle down the "Shell" of the cap with the dremel to expose the two leads. After cleaning up the mess Commonly called "Goo" I must say, and this is extemely important .The "Goo" IS CORROSIVE and will eat away traces!!! I simply clean the two leads with electronics cleaner , tin the leads with 40/60 solder and attach the two leads of the new "Cap" to those, and voila' No traces lifted. No fighting with solder suckers and braid.
I remove the tape and newspaper and there ya go. 1) I never use radio shack capacitors, they are cheap mass produced peices of junk! 2) I suggest buying capacitors from TV Parts suppliers. 3) The newspaper and tape is a little time consuming and tedious, but afterall we are protecting the board. I thought I would share this little tidbit of nfo with you and I hope it helps.... Regards, Galaxybr8

[Petef56]

Sounds like a good plan to me. Thanks for the tip.

---pete---

[Galaxybr8]

Hi Pete, After some more serious thought, Im wondering if just wiggling the capacitors back and forth untill they break off at the board, then soldering to the "Pads" that remain would be quicker? I'm going to try that and see if it works better...Anything has got to be better than taking a chance on lifting the traces and thus damaging the board, and the paper tape ,dremel method is awfully time consuming..LOL

Regards, Galaxybr8

[glc]

I think if you are going to go through the trouble of replacing capacitors, you should do it right - and your first method looks like the best alternative to me to the "right" way, in spite of it being time consuming. Wiggling the caps and trying to break them off at the pads can crack traces! Multilayer boards are fragile enough without subjecting them to this kind of localized strain. Not only that, heating the actual pads enough to flow solder can play havoc with the intermediate layers. I'd recommend after you have put the new cap in, you use some RTV around the bottom between the cap and the board to steady and insulate things.

[Galaxybr8]

I have three caps that were swollen on a pentium 4 MB.. I simply twisted the caps 4 times each way and bent the caps to the side, the leads slid right out of the capacitor without a problem...Getting ready to replace the caps as we speak!!!! Galaxybr8

[Toaster]

Hey folks,
I too have done many cap replacements on numerous computer boards including graphics cards.
This method works best for me;

1. Identify the offending cap and procure replacement(s).
2. Work and wiggle the cap, without using too much force until the cap comes away from the board.
3. With your soldering iron (max 40 watts) apply heat to the -TOP- of the board, not the bottom, remove the lead, do not push it through.
4. Once the broken lead is removed, heat again, from the top, and when the solder melts, use canned air to blow out the solder -through- the board.

The number of caps I replaced for failures or modding is virtually incalculable, far too many to count. Then again, I got a soldering iron for my 7th birthday and fixed the family's TV on my 12th birthday. Oh....and Ill be 50 in October.

[Cricket]

Originally Posted by Toaster Oh....and Ill be 50 in October.

Wow, Toaster and I are the same age...of course he has much more computer tech knowledge than I'll ever accumulate.

Cricket

[Toaster]

Ah, you must have those pestering "senior moments" as well huh?

[Cricket]

Originally Posted by Toaster Ah, you must have those pestering "senior moments" as well huh?

If you mean the morning aches and pains...yes.

If you mean those moments when you forget what you're doing or why you're doing it...yes.

Forgetfulness...what?

But hey, 50 ain't that old...at least that's what I keep telling myself .

Cricket

[Galaxybr8]

Thanks to all that posted, I think Im going to go with Toasters' method.. it seems more logical and less messy..I just won a Mobo on the Bay for peanuts and found 8 1500mfd 6.3 volt caps swollen, two are leaking from the bottom and one is starting to leak from the top.. I have the replacements ordered (1500 Mfd 10 volt rubycon) Yea Im pushing 46 myself and I have my moments... Like losing my phillips screwdriver, looking for it for two hours and sitting down and discovering it was in my back pocket the whole time. I just had to buy a pair of 1.75 glasses for the surface mount components, without them I cant see the surface mounts worth a darn. Yep Im gettin old...But still rockin to Priest!!!!! Any guitarists in here?

[Toaster]

1. Morning aches and pains. "check"
2. Repetitive brain farts. "check"
3. Passers by; "Are you insane dood?" "check"
4. Still hooked on classic rock. "Ya bet'cha"
5. Glasses. "Um....just for reading."
6. Selective, proactive and practiced insanity. "Most definitely."


Nope, not a guitarist but I did mess with the drums. Never got any good at it though so I'll just praise John Bonham.

[glc]

3. Passers by; "Are you insane dood?" "check"

Heh - we've known that for quite a while..........

[HAL9000]

What are you talking about... I've always thought Toaster was quite normal.

[glc]

He's quite normal - if you consider this normal:

http://forum.pcmech.com/showthread.php?t=10107

[HAL9000]

Sure.. why not....

[Toaster]

Oh, c'mon man, that was tooooo fun. That was normal for me, finding the fine hairy edge of the law and flirting with it. However, since 9/11, it's too easy to get into trouble and not even knowing how I managed it.

[HAL9000]

I think I would have fun with this guy LOL... been a while since I've been in any kind of trouble.. but seem to scare some up every now and then.... try to be a lot more responsible with a kid... but somehow.. I think we'll both end up in trouble one of these days and we'll both be grounded LOL.... she wants to try my snowman stealing technique.

[Toaster]

Whilst we are under the guise of children and other; "Highly impressionable persons", we have to forgo some zaniness and other fun attributes of our youths.
Still, times have changed, the world has changed since our (read...my) childhood. To me, getting into trouble was an art form, how to get away with just so much.

[HAL9000]

LOL.. ya.. I've done plenty of that during my day... just enough to have authorities come after you, but not quite enough to go any further than that.