Re: Apple //c--Uh-oh!

[dalloff@freenet.columbus.oh.us (Dave Althoff)]

Earlier today, I (dalloff@freenet.columbus.oh.us) wrote:

: Uh-oh!

: I have a "ROM $FF" //c.  And it has been acting a little flaky.

Well, thanks to Steve Buggie, it is now a ROM $00 //c, and it isn't flaky
at all.

: The net.wisdom was that I had one or more bad RAM chips.  Okay.

: So, over the weekend, I carefully desoldered all eight of the main-bank
: RAM chips, installed sockets, and replaced the RAM (well, I had to...I
: damaged or destroyed most of the old chips getting them out...)

: Trouble is, in extracting one of the RAMs, I managed to also destroy the
: small yellow part, presumably a capacitor or diode, identified as "C8" on
: the board.  8-(

: Question:  What is this thing?  What value is it, so that I can replace it?

Answer:  Several people have identified it as a bypass cap.  Thanks!  I
have found that the system does work without it, though I should replace it.

: As I am a brave person, I powered up the machine anyway.  No *BEEP*, but I
: got a screen full of hi-res graphics that looks like a bunch of green and
: purple "A"'s.  This is worse than the machine was before I started surgery.

Well, my upgrade ROM arrived today.  So I wanted to hurry up and install
it.  So I did, and I powered up the machine, and it worked fine.  So I put
it back together, and it quite working.  I took it apart and it worked fine.

Remember that I installed sockets for the RAM?  That raised one of the
chips up just enough that the disk drive chassis shorted across the legs
once the screws were installed. A well-placed chunk of electrical tape
solved the problem.

Thanks for all the advice!

--Dave Althoff, ][.

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