What about clock/nvram battery?
I have a 4400 which wouldn't start up until a new battery was in place.
Chad
Mel wrote:
Jeff,
Thanks for your advice.
I have several spare Mac IIci(s).
Tried switching off the power strip, switcing it on
and then wihtin a second or two hitting the on switch
separately form the keyboard and then from the switch
on the rear of the CPU. Nohting.
Pulled the power supply from a unit that was known to
be working and R&R with the power supply in the CPU
that was not working. No soap.
Finally R&R the internal drive with my data and
software and swapped it into another IIci CPU. Booted
up and everything works. in other words, I gave up.
However, I shall use your advice on the CPU that was
not working and experiment by trying some of the fixes
you suggested to see if I can make it operational.
Thanks for the tips and the benefit of your
experience.
Mel
--- Jeff Walther <[EMAIL PROTECTED]> wrote:
At 15:30 -0400 08/04/2005, System6 wrote:
Date: Thu, 4 Aug 2005 06:34:58 -0700 (PDT)
From: Mel <[EMAIL PROTECTED]>
This morning, when I hit the start button, the
three
lights above the three buttons (num lock, caps lock
and scroll lock) and the green light at the lower
right of the CPU came on simultaneously; the CPU
emitted a very short chime but the CPU never came
on
nor did the monitor.
First, you'd probably have better luck with this
question on Vintage
Macs list, because it is a hardware question, not a
System 6 question.
Second, there are two possibilities. You could have
a failed power
supply or a failed motherboard.
Power Supply: I don't remember the details,
unfortunately, though
some time with Deja News might pull up relevant
posts, but there's a
fairly common failure mode for the power supply
which, IIRC, may
cause this issue.
Logic Board: On these old logic boards the
electrolytic capacitors
leak and the leakage is corrosive. Pull the LB,
examine it closely,
holding it at various angles to the light and look
for discolored
areas (brownish) in the rear right corner. If you
find some, clean
it up with swabs and isopropyl (rubbing) alcohol.
Examine the area
carefully for pitted and corroded leads and solder.
You may find
connections that are eaten through. An ohmmeter
(continuity meter)
is handy for this examination.
Some folks have had luck simply cleaning the
corrosive off, but for a
good fix, you need to remove the old caps and
replace them,
preferably with tantalum caps which won't leak.
The surface mount electrolytic caps are the little
round silver cans
on teh board. There's about a dozen fat ones
(~1/4") and a handful
of thin ones (~1/8").
Marc Schrier's Clock Chipping Home Page has
instructions on removing
surface mount resistors using the two soldering
pencil method and
this is relevant to remving SM caps as well.
Replacement caps in tantalum or electrolytic are
available at
Digi-key and other places.
The unfortunate fact is that a huge number of these
grand old
machines are experiencing this type of failure.
We're seeing a lot
of the SE/30s with the same problem over on the
Classic Mac list.
I had this failure in my IIci back in the mid-90s
when a IIci was
still worth close to $1000. I had to bypass a
corroded via (a hole
that takes a connection from front to back of
circuit board) with a
bit of wire wrap to fix mine.
Jeff Walther
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