[NTLK] [OT] Mac Classic broken -- leaked caps?

[Владислав Коротнев]

OK, so what I've done is wipe the electrolyte with vinegar to
neutralize it, then cut off the caps, and cleaned under them too.
After that I wiped it all with isopropyl. Then installed all new caps.
I decided not to put pack the PRAM battery since it's useless at it's
age, and if it decided to leak things would be not fun.
Hopefully the corrosion won't start again for some reason.
What we have now is:
- It boots from either the ROM disk or the HDD, keyboard and mouse work fine
- There is still completely no sound output on the speaker (haven't
tested the line out)
- The floppy glitch seems to have gone too
- Neither Reset nor NMI buttons on the side work.

Guess the electrolyte did eat something on the board (you can see two
totally blacked vias near the analog connector, not sure if they are
anything related but I couldn't get them clean).

Still... http://cs629122.vk.me/v629122119/15f71/TTufdLmvDRY.jpg

Also I suspect it doesnt see the RAM properly... Either that or my
memory about it's RAM size is not right, it shows 2MB RAM installed.
http://cs629122.vk.me/v629122119/15f9f/8WY-5b3x0q0.jpg


2015-10-18 3:32 GMT+06:00, Bradley Mattice <bradwart at gmail.com>:
> Your best bet is to wash the board with a 50/50 vinegar and water solution
> to neutralize the electrolytes, then rinse with isopropyl alcohol, then with
> distilled water. I've done that to keep boards from getting any worse until
> I can recap them. Otherwise the electrolyte will eat traces on the board and
> require more extensive repair, if it doesn't render it dead entirely (the
> Quadra 840av board is the most sensitive to this).
>
> Sent from my iPad
>
>> On Oct 17, 2015, at 1:04 PM, Владислав Коротнев <vladkorotnev at gmail.com>
>> wrote:
>>
>> Bringing this up again.
>> Every vintage computer collector once in a while has an "Oh shit"
>> moment when opening up one of their favorites.
>> I finally got to open up my Classic and this is what I found
>>
>> http://cs629122.vk.me/v629122119/15d79/yUUQh0oAFkQ.jpg
>> http://cs629122.vk.me/v629122119/15d82/qbHCCH4figE.jpg
>>
>> I didn't wipe the dust off it (except for a few of the chips, but not
>> off the board at all). It's all some kind of sticky liquid.
>> Also I noticed the metal frame the whole thing is built around has got
>> some corrosion in the bottom-back-righthand corner. Not sure where it
>> got from, last time I opened it (circa 2010) it was totally fine.
>>
>> Also the ROM chip is slightly different from what I remember having on
>> the other Mac that had to be turned into an oscilloscope...
>>
>> Measuring out the caps' sizes and getting new ones asap, meanwhile,
>> brushing the board with some 95% alcohol just to get it a bit of a
>> chance to start.
>>
>>
>> 2015-09-21 4:51 GMT+06:00, arceeHS <arceehs at gmail.com>:
>>> Hi
>>>
>>> Another bit of info. It's for the SE/30 but everything applies here also
>>>
>>> http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html
>>>
>>> aichess
>>>
>>>> On 9/20/15, Владислав Коротнев <vladkorotnev at gmail.com> wrote:
>>>> We don't have the exact brand of "magic bubbles" but i'll see if i can
>>>> find a substitute
>>>> .
>>>> Regarding the bars btw, I once had a Mac Classic back in 2012 that
>>>> shown funky blinking patterns. I suppose it was a faulty/improper ROM
>>>> or SIMM. Anyway soon after the HSync generator/amp failed and I turned
>>>> it into a funky goniometer-alike music visualiser, still somewhere in
>>>> my stacks of stuff... So try and check your ROM to be seated properly
>>>> as well :)
>>>>
>>>> ----------------------------------------------------------------------
>>>>
>>>> http://newtontalk.net/
>>>
>>> ----------------------------------------------------------------------
>>>
>>> http://newtontalk.net/
>>
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>>
>> http://newtontalk.net/
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