13 Apr
2008
13 Apr
'08
2:29 a.m.
On Thu, 2008-04-10 at 12:57 -0500, Mark Tapley wrote:
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.
Anywhere you get tinned connectors that are even a little bit exposed to
the outside environment (near a ventilation grille), you get problems.
Or at least, that's been my experience.
The problems caused by the capacitive keyboards on Ensoniq ESQ- and
VFX-family synths nearly sunk the company (maybe they did, at that).
All this because of a little multiplug between the two halves of the
keyboard PCB, positioned right under the key bed where moisture would
get at it. Nearly all of these have had the plugs removed and the
connection hardwired.
Gordon