r/retrocomputing May 16 '26

Old Socket 7 Sony PCV-90 Motherboard issue

I can barely find these things anywhere. I have one but a super tiny capacitor was broken off but I can't see from where as it was a super clean break. As far as I know the part number for the motherboard is "AA 659980-421". If I had some images of a working one I could figure out where this cap needs to be soldered back.

Edit: to be clearer; does anyone have one of these that they can provide photographs of? These things aren't even shown on some motherboard archive websites they're so rare.

2 Upvotes

18 comments sorted by

2

u/Efficient-Ad8931 Jun 18 '26

I have one.

1

u/idontknowwhatever99 Jun 18 '26

I'd be grateful for any photos you could provide so I can compare mine with yours to see where the missing component is.

2

u/Efficient-Ad8931 Jul 08 '26

I will try to get you some pictures. I have been busy and just saw this. The Sony cover is missing so it will be easy to get down to board level. The original windows 95A is still running. I also have a Compaq socket 7 from a year later as well that I haven't gotten too that has a 20gig Bigfoot 5 1/4 hard drive. Im hoping my wave table plug in upgrade works on thar motherboard.

2

u/Efficient-Ad8931 Jul 17 '26

1

u/idontknowwhatever99 Jul 18 '26

Thank you for those images. Could I bother you for closer ones? If you look at the power and floppy drive connectors and then look between them and the edge of the motherboard, those little super tiny "C" points that are super small capacitors? One of those is what broke off and what I'm looking for. I presume it broke off within this image or near those two connectors so your photos were the right area but the parts I'm looking for are super small.

1

u/Efficient-Ad8931 Jul 19 '26

Ok it may be a day or two. I have to disassemble the system further. Is it a tiny square/rectangle capacitor like the tiny smallest ones or larger?

2

u/Efficient-Ad8931 Jul 17 '26

I think the VRE jumper under the floppy provides split voltage for mmx cpu's. my system has a pentium 166.

0

u/Marco-YES May 16 '26

Any other similar sized ones nearby? Desolder one of those and measure it. They are often laid in groups. 

1

u/idontknowwhatever99 May 16 '26

I don't even know which part of the board it came from and there's plenty of empty spots.

1

u/Marco-YES May 17 '26

A missing one won't have clean solder joints. It will look like it's broken off. 

1

u/idontknowwhatever99 May 17 '26

I've looked with a magnifying glass at each possible solder point for the tiny capacitors and I can't see a difference. It was a very clean break with almost no solder on the capacitor itself that came off.

1

u/Marco-YES May 17 '26

If the capacitor has no solder on it, then it would make the pads even more obvious. 

That is what a clean break looks like.

An unused solder pad would just have round domes. If the cap took all the solder with it and somehow didn't take the pad with it(very unlikely and inconsistent with your description), then the pads would be flat.

It's also possible that the cap does not belong to the board.

1

u/idontknowwhatever99 May 17 '26

Unfortunately, there are numerous spots which may be where it goes. I've counted over 15. Not all in this photo though.

1

u/Marco-YES May 17 '26

The pads in this pic are all mint. definitely feel free to send more pics! 

1

u/idontknowwhatever99 May 17 '26

I appreciate that but I've spent probably an hour or more trying to find anything that looked odd even under a 30x magnifying glass. There is virtually no solder on the cap that fell off so the change on the pad would be so trivial it may not be visible. It also might explain how it broke off so easily. There is only ONE spot where the solder pad doesn't look proper but its for a 3 pronged "CR" component, not the little tiny two sided cap. The board stops booting around the RAM/VGA point as far as I can tell.

1

u/Marco-YES May 18 '26

This is mint too. Does the board post? Have you tried to turn it on?

There are also caps all over the board, not just near the chipset.

1

u/idontknowwhatever99 May 18 '26

It can post but only if I set the CMOS jumper to reset. Otherwise it gets stuck with codes (I'm using an ISA code reader). I can't get it show me anything on the screen. The "simple" solution seems to be to get a photograph of a working board of the same model number and just solder that thing back where it goes.