Apple III - mouse dropping on motherboard !!! HELP

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Apple III - mouse dropping on motherboard !!! HELP

I got a A3 to restore. I pulled the motherboard out and it has a lot mouse pee and little pellets all though the center part of the board. No nest though.
How best to clean???

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Re: Apple III - mouse dropping on motherboard !!! HELP

Years ago I ran into a similar issue with a Sider Hard Drive. A customer brought in the drive for repairs. It did not work and I noticed a unpleasant smell (not burned components) coming from the drive. Upon disassembly and close inspection I found something crystallized on the controller board. The customer told me that his cat liked to sleep on the top of the warm drive. Im guessing it was cat pee. All the components were soldered on and since it did not work anyway, I washed it in the sink with lots of rinsing with fresh water. After blowing it off and warming it up with a blow dryer to make sure it was completely dry I plugged it back in and it worked. Not enough conductive liquid to really short out the circuit and burn things but enough to make it stop working.
The A3 has sockets which makes places that will be hard to rinse but it may be worth a shot. After thoroughly rinsing, dry it quickly so to keep the wet time as short as possible. I know this sounds terrible and drastic but it worked for me and the Sider worked for several years until I lost track of it.
wm

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Re: Apple III - mouse dropping on motherboard !!! HELP

Some electronic cleaner fluid like from Kontakt Chemie or Isopropanol 99% should do the job. After that using some destilled water to remove remaining fluid or isopropanol. Than blast the PCB carefully and dry it as mentioned before while I also recomment to give it some days to dry themselve.

Please use some ESD wriststrap (band) when handling... just to avoid electrostatical discharges against the PCB electronics.

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Re: Apple III - mouse dropping on motherboard !!! HELP

It's all TTL, so if I were to clean mouse or rat urine from a PC board, I would use Simple Green
dissolved in water. You need something fairly strong to remove that kind of substance. Also, if
you don't get it all out from underneath the chip sockets, it will smell like a rat house for a
long time. Do yourself a favor and take a detailed photo of the IC's in their place, then remove
and clean them separately. I clean chips by dumping the ICs into a fine screen strainer, spray
them with simple green or Spray-9 cleaner, rinse them with the faucet sprayer and dry them by
hand. It's OK to submerse a PC board in water completely for several minutes while washing with
a cloth to remove the debris, but it's also important to rinse away ALL remnants of the cleaner (which
is a liquid to begin with) with CLEAN water. Fast drying can be accomplished with dry shop air over
and under all the IC sockets followed by a WARM AIR source. (such as a hair dryer or sitting in front
of (say) a warm heat register) The key here as you well know is to get the board completely dry.
Once that's accomplished, you can re-populate the board with your clean IC's knowing well that
the pins/legs, etc are starting out with good contact. Before applying power, double-check that your
IC's are all pointing in their proper direction. (!) Good luck!

Hope this helps...

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Re: Apple III - mouse dropping on motherboard !!! HELP

Thanks everyone for all the suggestions.
It is soooo bad, that I think the wishwasher solution might be best. Using dish soap, not wishwasher saop, after last rinse, take it out, re-rinse with distilled water, then blow it out with with my air compressor. Then dry in the sun, turning every few hours for a couple days. Next pull and re-seat all IC's. Let it double dry for a day, then test.

PS question about the keyboard lamp. I've read that the A3 will not boot on power on with a dead lamp. But you have to press reset. Can I replace a lamp with an 3.2vf LED, and have the power on circuit work correctly? Or does it have to be an incandescent lamp? If it has to be a lamp, where to source the correct size and voltage?
Thanks again

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Re: Apple III - mouse dropping on motherboard !!! HELP

I would remove the ICs before the M/B wash and wash the ICs separately. If the IC legs look really oxidised, give them a quick rinse in Tarn-X and rinse/dry thoroughly.
wm

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Re: Apple III - mouse dropping on motherboard !!! HELP

Well, NO joy!!
I was very careful for static throughout the whole process. But the A3 did not boot. I let it dry in the sun, and turned it several time. I reseated all IC's, I cleaned many IC pins that looked a bit corroded.
I checked the PSU, and it appears to be giving 5 volts.
Any suggestions, other then buy a complete new set of 74xx, etc, IC's and trying again?

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Re: Apple III - mouse dropping on motherboard !!! HELP

Well it kind of lives. Starting new thread...

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