Recap question?

[redrooster]

I tried to replace a couple of caps,3300uf,6.3v next to the CPU on a RS690M03 motherboard and it has been a major hassle,to cut a long story short I drilled out the holes on one of the caps just oversize to what it was originally. Then I thought Oh no! what if it is a multilayer PCB board? Is it multilayer? If it is how can I fix it? What does a cross section of the board look like at that spot so I know what I'm doing? I know that's a lot of questions but I really do need to know if the holes are sleeved with solder and does the solder connect with the copper on one side with the copper on the other?

[euromatlox]

Re: Recap question?

It's not recommended to do drilling of bigger holes like that.

What you can do is to clean (most of) solder around those mistakenly drilled holes. Possibly all 6.3v caps are connected in parallel, like is told here:

http://www.capacitorlab.com/basic/index.htm

Then check by measuring (undrilled 6.3v capacitor) holes (+/- holes), that they are not shorted to cause any extra problems. You can do special soldering to add 2 caps into one place..or perhaps use larger capacitors than original ones (so that total capacitance is about the same as 'original').

..and then hope for the best..no guarantees available

[c_hegge]

Re: Recap question?

I've accidentally destroyed pads too. On the CPU VRM out, the caps are all connected in parallel, so another option is just solder them in as usual and add some wire to the next cap, like so...

[redrooster]

Re: Recap question?

You guys are excellent and this is a good site. I thought I was going to have to throw the computer out! Thanks fellas.

[redrooster]

Re: Recap question?

OK I have soldered in the parallel lines and they are shorted between them? Is there a schematic or something so I can tell what goes where to find why its shorting?

[c_hegge]

Re: Recap question?

You mean that the + legs are shorted to each other (and the - legs to other - legs)? If so, they're supposed to be. If you mean that the + legs are shorted to the - legs, then that's a problem.

[redrooster]

Re: Recap question?

Yes + legs are shorted to - legs but it wouldn't be a problem if I knew the layout of the board and I know what Im doing? Ive been looking (googling) for a service manual for this motherboard but so far nothing. M/B# RS690M03-8EKRFS2H

[euromatlox]

Re: Recap question?

Just checked about the matter from old MSI socket A motherboard. Diode tester beep is loud, but if measured using ohmmeter reads about 35ohms = not shorted. No CPU on that board.

[redrooster]

Re: Recap question?

Just checked about the matter from old MSI socket A motherboard. Diode tester beep is loud, but if measured using ohmmeter reads about 35ohms = not shorted. No CPU on that board.

Im getting 0.5 ohms across them with ohm meter?

[selldoor]

Re: Recap question?

Am I missing something here the bottom board view suggests that there is one big sheet
of copper so if you solder two legs through to that they are bound to be short.
We cant really tell but I suspect (Guess) that one leg will solder to that but the other leg would have been insulated from it, and will connect to a trace on the top of the board?

NB this could all be BS - Id use the flag but it takes up a lot of space

[redrooster]

Re: Recap question?

Am I missing something here the bottom board view suggests that there is one big sheet
of copper so if you solder two legs through to that they are bound to be short.
We cant really tell but I suspect (Guess) that one leg will solder to that but the other leg would have been insulated from it, and will connect to a trace on the top of the board?

NB this could all be BS - Id use the flag but it takes up a lot of space

This is all new to me,this is my first attempt at fixing a motherboard, so you could tell me anything and Id believe it.LOL With a capacitance meter across them it measures 019uf on the 20000uf setting? How do I work out 5 x 3300uf in parallel?

[euromatlox]

Re: Recap question?

I remeasured with Duron CPU connected into the old MSI motherboard. Now it reads about 6 ohms (without cpu 33 ohms). I guess lower readings are possible with different processors, so it's better to remove processor from it's socket to be sure about the readings. It's a good practice also check what is the shorted reading of ohmmeter, one of my multimeters shows 2ohms, and the other 0.4ohms..better use the more reliable one. Of course the PSU is also highly recommend to disconnect, but I guess that already has been made. I have myself replaced many caps without completely removing the motherboard from pc case, with some wires connected, but PSU disconnected.

[selldoor]

Re: Recap question?

I dont know either hehehe thought Hegge might comment.

BUT if you look to the left in the picture is that an untouched cap? The top leg appears to be soldered to this side of the board but the bottom leg may be just soldered to the "Through" and is insulated from this side - it has a dark ring??. If you could check that.

Common sense hahaha we wouldnt be doing this if we had any
suggests you shouldnt be soldering both legs to the same trace.

[redrooster]

Re: Recap question?

I measured it with the cap meter and got 16.500uf on a lower setting, I put that into a calculator and it came up nearly exactly right! 16.5uf,I got 17uf when the meter settled down after a while, So there is nothing wrong with it. Yaaay!

[selldoor]

Re: Recap question?

Just been out to the garage for an old mb Freezing out there - bet its not in Oz tho Finland
is likely to be colder. Anyway on mine I can see one leg is NOT soldered to the bottom of the board plate there is a gap so it is insulated from it. I guess all !!! we need to do now is figure out how to put a cap in so it is isolated . I have an idea but dont know if it would work. Solder in the correct leg but isolate the other but then use a wire as hegge suggested to connect it to the cap that is connected good if it is ok to have them in parallel Tricky but not impossible.

[redrooster]

Re: Recap question?

Its hot here,its 1am and I'm sitting in front of the computer in a pair of shorts with a fan going,been having 40 Celsius plus days for days on end.It looks like this M/B might be OK now Ill know when I fire it up?

[selldoor]

Re: Recap question?

Dont be looking at the mb when you do if the caps are short they might pop

[redrooster]

Re: Recap question?

Dont be looking at the mb when you do if the caps are short they might pop

Don't worry I always turn these iffys on with a long stick.LOL

[c_hegge]

Re: Recap question?

If there is really a short, then the PSU should just shut off. I doubt it will explode the caps. Give it a try and see what happens.

[redrooster]

Re: Recap question?

Yes, its firing up OK,the CPU fan doesn't come on for 5 or 10 seconds or so is that normal?