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Simasimac SE/30, capacitors replaced, no luck.

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Neosodium

Experienced Member
Joined
Nov 30, 2010
Messages
119
Location
Oxfordshire, UK
Bought an SE/30 off eBay recently (been wanting one for years as it was my first computer when I was young) and It is displaying the horizontal lines on powerup. Battery had leaked a bit but cleaned up okay and removed the remains. Cleaned up the ROM and RAM sockets and Replaced all the capacitors (aside from the big blue ones) with surface mount tantalums but still the same symptoms.

Also tried pulling up the audio chip with a 1k resistor but no change.

Anyone know something I might be missing or is this board beyond repair? It would be a shame as the analogue board, power supply and monitor are absolutely fine.
 
Neosodium said:
Bought an SE/30 off eBay recently (been wanting one for years as it was my first computer when I was young) and It is displaying the horizontal lines on powerup. Battery had leaked a bit but cleaned up okay and removed the remains. Cleaned up the ROM and RAM sockets and Replaced all the capacitors (aside from the big blue ones) with surface mount tantalums but still the same symptoms.

Also tried pulling up the audio chip with a 1k resistor but no change.

Anyone know something I might be missing or is this board beyond repair? It would be a shame as the analogue board, power supply and monitor are absolutely fine.
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You say the battery leaked, have you gone over all the traces near there with a light and magnifying glass? The battery "acid" can destroy traces, it's possible it ate through something.
 
The leakage was minimal and I can examine it closely when the board is out next, but we have another problem now. My friend who did the cap replacement said the problem may have been the tantalum capacitors overheated from the soldering and quit working so we changed them for barrel electrolytics. One of them got caught as we were removing the board last and pulled the solder pad up. :mad:

Is there a way to repair this? I would really like a working SE/30.
 
Neosodium said:
The leakage was minimal and I can examine it closely when the board is out next, but we have another problem now. My friend who did the cap replacement said the problem may have been the tantalum capacitors overheated from the soldering and quit working so we changed them for barrel electrolytics. One of them got caught as we were removing the board last and pulled the solder pad up. :mad:

Is there a way to repair this? I would really like a working SE/30.
Click to expand...

Well, depending on how much of the trace to the pad is there you can scrape the soldermask off (the green stuff) and solder a jumper from the exposed trace to the terminal on the part. If that doesn't work, you will have to ohm it out or look at a schematic to see what part(s) it attaches to and run a jumper from there.
 
RWallmow said:
You say the battery leaked, have you gone over all the traces near there with a light and magnifying glass? The battery "acid" can destroy traces, it's possible it ate through something.
Click to expand...
There's no acid in these batteries -- they work in a basic environment, the electrolyte is KOH and that's what can destroy the traces.

As far as damage, battery leakage can be really nasty to a PCB. It's not only the visible traces that can get damaged but there can also be damage to the non-visible non-accessible (internal) traces between the layers. This is a real board killer with battery leakage.
 
Stone said:
There's no acid in these batteries -- they work in a basic environment, the electrolyte is KOH and that's what can destroy the traces
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Thus my quotes around "acid" in my reply, wasn't planning on going into the acid versus base discussion, just trying to point out that whatever leaks out, that most people would (incorrectly) call "battery acid", is bad and needs to be cleaned up, and the damage inspected.
 
Stone said:
"Battery acid" *IS* bad, really bad, but it's in your car's battery. :) It's H2SO4, aka sulphuric acid.
Click to expand...

Yeah, most people call what leaks out of ANY battery "acid", even when its not, I was just keeping things simple ;-)
 
Oh dear... well it didn't look at all bad once cleaned up and the leak was localised within an inch of the battery. If this board is damaged beyond repair, is there a way to get hold of a new system board?
 
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