Bringing up an older Mac

[Mark Tapley]

At 12:00 -0500 4/10/08, David Griffith wrote:
>I've just brought up a Mac SE/30 with fresh disks and noticed that the
>monitor occasionally gets wavy or shudders.  How should I proceed in
>fixing this?

	I had a long, long series of problems with my Mac Plus. They 
got pretty much cured when I took loose the power cable connecting 
the Analog/video board to the digital board, cleaned the pins (sanded 
lightly and wiped with ethanol), and put some silicone oil spray on 
to inhibit corrosion. I had previously done this at the digital board 
end, but the resistance (ohms to tens of ohms, and variable, 
responding to temperature and vibration) was at the analog board end. 
I finally discovered I could diagnose these by using an ohmmeter 
between the solder pads on the back sides of the boards at either end 
of the cable.
	I don't know how many differences there are between SE/30 and 
Plus, but some, for sure. Be very careful disconnecting at the analog 
board end of the cable - pull too hard, and your hand can smack into 
the thin end of the CRT, letting the vacuum out. I have a .pdf of the 
Apple Service Manual for the SE/30, which I'll be happy to forward 
(off-list, obviously).

	On the Plus, there are also a set of variable resistors on 
the analog board setting various parameters (width, height, etc.) of 
the video. Those might also be corroded. Running them back and forth 
and then back to the original settings might clear that, or some 
contact cleaner (which is probably a better treatment for the 
connectors than what I list above) might be a good idea.

	Finally, capacitors on the analog board might be going bad. 
An ESR meter could give you some indications there.

	Additional clues from somebody with an SE/30 would be very valuable!

At 12:00 -0500 4/10/08, Ian Primus wrote:
>But I have a
>book at home, forget the name, but it's a Macintosh
>repair guide that has a lot of good info to help
>pinpoint failed parts. It has a purple cover. Anyone
>remember this book? This is going to drive me nuts all
>day. :)

	The "Dead Mac Scrolls"? "Macintosh Repair and Upgrade 
Secrets"? Google for Larry Pina, I think he's the most-recognized 
author in this area.

At 12:00 -0500 4/10/08, David Griffith wrote:
>It happens perhaps once every ten seconds.  The disturbance is something
>like a ripple or wave that crawls up the side of the screen.

	Oh. Probably my advice above is good in general but not 
specific to this problem. I think the Pina books may well address it 
though. If Jeff W. is listening, he can probably verify that.
-- 
						- Mark, 210-379-4635
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