At 07:30 PM 1/13/2009, Mark A Kippert wrote:
>What the heck? One note, it is keeping time. It's just the display
>that fades in and out as you rev and let off the gas.

The clock has no separate ground, so that's not an issue except maybe
where the clock connects to the panel -- I forget if it's soldered or
what.  If it *is* soldered, a cracked joint is an ideal place for the
sort of behavior you're seeing.  Power comes from terminal 14, pin 5,
fed by the interior-light circuit.  The draw is probably a milliamp
or two, also ideal for weird flaky connection problems.

But my bet is bad solder* at or inside the clock itself. I'd pull the
panel, give it power with AAs or whatever, 12v from T14p5 to T14p3
(ground), and gently wiggle stuff...

*I'm a nut about bad solder.  I've fixed more stuff by just reflowing
every joint on the board...and I also have a little technical
knowledge about solder's fatigue life, which is close to zero.  Any
component that vibrates, or thermal-cycles, is trying to pull itself
out of the board, and the cracks can be invisible at 20x
magnification.  Digression...

*in this case, flaky contact at the +12 terminal is just as likely --
either one can make little diodes that form and break down and so
forth.  You only see this sort of thing with tiny currents like the
clock draws.

d

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"