14 Oct
2013
14 Oct
'13
6:57 p.m.
On Oct 14, 2013, at 8:30 PM, Liam Proven wrote:
I decided to take my life and my capacitors in my
hands and try to
power on the somewhat grubby old Mac+ I was given recently.
I hooked up a keyboard and mouse and plugged it in.
The floppy drive makes a very short whine, the Mac emits a fairly
basic monophonic happy-Mac beep, and sits there humming quietly at me.
However, the screen does not light up.
It /sounds/ like the logic board is initialising OK but the screen isn't.
Is there much troubleshooting that someone fairly electronically
incompetent can do to one of these?
I have a few books on troubleshooting old Macs from 128K to SE.
I'll be glad to scan a few pages if necessary.
However, the birds-eye view would say that it's either the CRT
or something in the analog board; my guess is the analog board,
though transatlantic prognostication without any low-level
detail is necessarily an inexact thing. :-) In either case,
the analog board is more likely (in my recollection) to go bad,
and it supplies both the video signal and the power supply to
the CRT. It also supplies the power to the logic board, so
it's obviously not TOTALLY gone. But it could easily be
something in the HV supply or the logic chain.
Do you have meters and/or oscilloscopes to determine potential
problems? I assume you've osmosed enough of the general
warnings about CRTs and HV supplies from this list to know that
you should take at least some basic precautions when poking
around inside.
- Dave