rasz_pl wrote on 2024-04-04, 14:52:

they never were, that yellow stuff underneath is copper sheet, they are all connected to it, all the little guys and that big ca […]
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psaez wrote on 2024-04-04, 14:36:

Originally they were separated

they never were, that yellow stuff underneath is copper sheet, they are all connected to it, all the little guys and that big capacitor hole, they are all one the same VCC plane.

psaez wrote on 2024-04-04, 14:36:

, but they are mixed now, I mean they are connected with tin. And its absolutely impossible to unconnect them. I tryed everything. So I openned this post to request for help.

its all ok, you didnt mess anything up. Old soldermask - the paint covering copper - started flaking off and that caused your solder to start wicking up the copper plane due to surface tension.

psaez wrote on 2024-04-04, 14:36:

So... then.. if I start the motherboard.. will it break if the red circle is still connected with the positive leg of the capacitor throught that tin on the reverse of the motherboard?

no, it was always connected to it, that capacitor is filtering voltage coming from the coil

Pickle wrote on 2024-04-04, 13:21:

I think the problem was the cap leg was forced into the small via and not the larger one

majestyk wrote on 2024-04-04, 12:55:

Aaah, I see - I got this totally wrong in the beginning. I understood you were in doubt, because the blank area had become large […]
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Aaah, I see - I got this totally wrong in the beginning. I understood you were in doubt, because the blank area had become larger and you were unsure if you can connect them when soldering the new capacitor. Silly me...
Of cause you do not have to connect them, you can keep everything seperated as was the original stuation. Just do as everybody does, replace the capacitor and make exactly two (tiny) solderings. There´s absolutely nothing wrong with the original state.
Then again, what was the problem?
And what exactly do you mean by "mixing" the soldering points / vias?

well guys... something is wrong now... first I put straight all the legs of the capacitors heating the tin, and cut them. After that I used a magnifying glass to check that all is OK, obviously, the thing from the first photo I uploaded here is still the same, but as you told me is fine, I tought it whould work. Then, I connected the motherboard, and first it started correctly, and even entered to Windows 98, but suddenly it rebooted and speaker started to make a crackling noise and compact disk reader started to reset itself constantly and screen turned off. If I shut down and start again, the same.

I tryed removing everything, and simply waiting on the screen that tells you that there is no boot, and the same, suddenly it comes to black and starts to reset constantly.

I'm very frustrated, don't know what is happening, it is very sad that I think I broken the motherboard

I don't think it's dead. Should be fixable. I would double check if all caps are correctly oriented. Also poke around with a multimeter and see that you don't have a short or bad continuity.

Correct me if I'm wrong but often caps are sitting in parallell so it would perhaps work (kinda) with only one cap but the circuit is out of spec.

I leave it to more knowledgeable people to give you tips exactly what to look for as I'm just a beginner as well.

If they are reversed they might also get hot, but the right way is with the multimeter.
A post code card wouldn’t hurt.

Pickle wrote on 2024-04-04, 19:31:

If they are reversed they might also get hot, but the right way is with the multimeter.
A post code card wouldn’t hurt.

I have a post code card, but never used it, please can you tell me how can it help me?

Joakim wrote on 2024-04-04, 19:11:

I don't think it's dead. Should be fixable. I would double check if all caps are correctly oriented. Also poke around with a multimeter and see that you don't have a short or bad continuity.

Correct me if I'm wrong but often caps are sitting in parallell so it would perhaps work (kinda) with only one cap but the circuit is out of spec.

I leave it to more knowledgeable people to give you tips exactly what to look for as I'm just a beginner as well.

I'm totally newbie, how can I do that? I have a multimeter but I don't understand what you mean, bytheway, all the caps are equally oriented than before

Some post codes have leds for the voltage if it’s anything but solid might point to a problem on that voltage rail. The hex codes can tell you where you are in the boot process and give you any idea what system is failing. You do need the book to lookup the codes.

Simple test with multimeter put black lead on the negative side of cap and red lead on the positive side. In continuity mode it might have short beep (charging cap) but should not be continuous.

yep, does totally sound like you soldered one of the caps in reverse polarity and it just managed to cling to his life for a short while
you did take photos of all caps before removing them, and with all capacitors removed, right? 😀 now its time to compare

rasz_pl wrote on 2024-04-05, 05:38:

yep, does totally sound like you soldered one of the caps in reverse polarity and it just managed to cling to his life for a short while
you did take photos of all caps before removing them, and with all capacitors removed, right? 😀 now its time to compare

Pickle wrote on 2024-04-04, 19:52:

Some post codes have leds for the voltage if it’s anything but solid might point to a problem on that voltage rail. The hex codes can tell you where you are in the boot process and give you any idea what system is failing. You do need the book to lookup the codes.

Simple test with multimeter put black lead on the negative side of cap and red lead on the positive side. In continuity mode it might have short beep (charging cap) but should not be continuous.

Joakim wrote on 2024-04-04, 19:11:

I don't think it's dead. Should be fixable. I would double check if all caps are correctly oriented. Also poke around with a multimeter and see that you don't have a short or bad continuity.

Correct me if I'm wrong but often caps are sitting in parallell so it would perhaps work (kinda) with only one cap but the circuit is out of spec.

I leave it to more knowledgeable people to give you tips exactly what to look for as I'm just a beginner as well.

well I doublechecked it and the four capacitors I changed are correctly oriented... and It took me two days of work to change them, so I'm not capable of removing them again to test them. Does exist a easy way to test them without removing them from the motherboard?

I'm a total newbie in electronic manipulation

any idea about what is broken or how to proceed now? i have a multimeter, but I don't know anything about electronic

PD: I'm trying a post card i bought, and it gives 7F76 code when the screens goes off. Also in the two columns of 4 vertical leds, the first one has the 4 leds on, and the second one has only the first and the fourth, but can't understand what that means. Is this post card: https://es.aliexpress.com/item/1005005450431935.html

Maybe there is just a broken/bad connection on one of the solder joints of a cap. You could test for continuity on the legs of the capacitors.

If they are in parallell as I guess many are, the + and - should all connect to each other for instance. You should get a continuos beeping sound when measuring + to + or - to - of two different caps in parallel. If one isn't connected you will have a lowered total capacitance probably similar to having bad caps and make the board unstable, but current is still flowing and maybe the board runs untill there is a heavy load it goes bonkers.

And please correct me if I'm wrong with the above I'm kind of thinking out loud.

how close are the replacement caps to the old ones i.e capacitance and voltage ,same type?

well guys, finally I disscovered which is the problem... was the graphics card! I changed a capacitor on the graphics card too, and seems the tin was not correctly welded, not visually, but internally, because a friend told me to test with another card and the motherboard worked perfectly! 😳

So I unwelded and welded the capacitor again at the graphics card and problem solved. Can't believe it.

That has to be a relief 😉
I’d say next time fix one thing at a time.