SOYO SY-5EMA+ V1.1 | He's dead Jim... or is he? \ VOGONS

SOYO SY-5EMA+ V1.1 | He's dead Jim... or is he?

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First post, by Lostdotfish

Posted on 2020-08-03, 15:42

Lostdotfish Offline

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So I picked up this motherboard off eBay a few weeks ago. Sold as working but when tested, dead. No beep codes nothing. Dead dead. Well, if you listened very very hard to the connected speaker, you could hear a very very faint pulse...

Well the seller ignored my request to return it hoping I'd go away. And I did, long enough for eBay to step in and refund me. Which leaves me with 1 dead Super Socket 7 motherboard.

On closer inspection, I noticed it comes completed with Wendell Capacitors of Doom from the height of the last great Bad Cap pandemic. Of particular note are the nasty green cans of death all around the CPU socket.

Cue a Bill of Materials for the complete replacement of all caps on this board. I ordered Panasonic FR series caps for their low ESR rating.

1CE1	1000uf		6.3v	8mm	12mm
2CT30	1000uf		6.3v	8mm	12mm
3CT31	1000uf		6.3v	8mm	12mm
4CT6	1000uf		6.3v	8mm	12mm
5CT5	1000uf		6.3v	8mm	12mm
6CT7	1000uf		6.3v	8mm	12mm
7CT8	1000uf		6.3v	8mm	12mm
8CT9	1000uf		6.3v	8mm	12mm
9CT10	1000uf		6.3v	8mm	12mm
10CT32	100uf		16v		6mm	8mm
11CT4	100uf		16v		6mm	8mm
12CT16	10uf		25v		4mm	8mm
13CT22	22uf		25v		5mm	8mm
14CT29	22uf		25v		5mm	8mm
15CT27	22uf		25v		5mm	8mm
16CT26	22uf		25v		5mm	8mm
17CT25	22uf		25v		5mm	8mm
18C74	22uf		25v		5mm	8mm
19CT28	22uf		25v		5mm	8mm
20CT23	22uf		25v		5mm	8mm
21CT24	22uf		25v		5mm	8mm
22CT21	22uf		25v		5mm	8mm
23CT20	22uf		25v		5mm	8mm
24CT19	22uf		25v		5mm	8mm
25CT17	22uf		25v		5mm	8mm
26C34	22uf		25v		5mm	8mm
27C46	22uf		25v		5mm	8mm
28CT18	22uf		25v		5mm	8mm
29C24	22uf		25v		5mm	8mm
30CT15	22uf		25v		5mm	8mm
31CT14	22uf		25v		5mm	8mm
32CT3	22uf		25v		5mm	8mm
33CT13	22uf		25v		5mm	8mm
34CT1	22uf		25v		5mm	8mm
35CT2	22uf		25v		5mm	8mm
36CT11	22uf		25v		5mm	8mm
37CT12	22uf		25v		5mm	8mm
38C38	47uf		16v		5mm	8mm
39C39	47uf		16v		5mm	8mm

Stay tuned for the next episode of "Is it dead... or only sleeping?"

Reply 1 of 4, by ykot

Posted on 2020-08-03, 16:54

ykot Offline

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I have a very similar motherboard, just "PRO" version, that will not cold boot. It also came with these green caps, but recapping didn't help - I've used polymer caps as replacement.

However, in your motherboard I see burned flux at the mosfers near CPU socket, so likely those have been replaced. I would guess that these have been replaced because of incorrect CPU placement, which caused short circuit. Have you measured CPU voltages at the socket?

Reply 2 of 4, by Lostdotfish

Posted on 2020-08-03, 18:21

Lostdotfish Offline

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ykot wrote on 2020-08-03, 16:54:

I have a very similar motherboard, just "PRO" version, that will not cold boot. It also came with these green caps, but recapping didn't help - I've used polymer caps as replacement.

However, in your motherboard I see burned flux at the mosfers near CPU socket, so likely those have been replaced. I would guess that these have been replaced because of incorrect CPU placement, which caused short circuit. Have you measured CPU voltages at the socket?

I haven't tested much of anything yet to be honest. Swap tested a handful of known good CPUs, ram modules and graphics cards and that was all.

The mosfet pads look too clean (other than the flux) to have been reworked (other than at the factory). I wonder if it was a component that couldn't be wave soldered and was hand placed as part of the finishing process....

I'm going to pop out all the 1000uf caps 1st and then try it again. I'd doubt the other caps are causing a problem but if that gets it working, I'll recap the rest for good measure. If not, well, it will have been a fun hour or so of soldering...

Reply 3 of 4, by Intel486dx33

Posted on 2020-08-03, 18:28

Intel486dx33 Offline

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I purchased a lot of 5 of these motherboards a few years back. The fat capacitors near the CPU socket are the ones that bulge.
I would start with those first.

Reply 4 of 4, by Lostdotfish

Posted on 2020-08-03, 18:31

Lostdotfish Offline

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Posts: 286
Joined: 2019-08-17, 11:49

Intel486dx33 wrote on 2020-08-03, 18:28:

I purchased a lot of 5 of these motherboards a few years back. The fat capacitors near the CPU socket are the ones that bulge.
I would start with those first.

Yup, there's one in particular that's got a rounded top. The faint pulsing sound on the speaker makes me think the main power supply to the CPU is wonky and since those caps all feed it, they we're my first suspects.

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