Dead Clock

[cal300SD]

W126 85 280SE with a dead clock in dash. Fuse not blown. Any suggestions for fixing, would be nice to see it working.

 

[Robert Cox]

My '86 W124 had a dead clock when I bought it. The most likely culprits are the electrolytic capacitors (condensors) which break down with age. I've been told the German ones are notoriously poor, and esp. since they fitted 16v rated ones which can't stand any voltage spikes.

If I recall, there are two on the clock circuit. Easy to get at once you get the instruments out. I bought replacements for 80c each at a local electronics store. I got 35v ones which are bigger and more reliable.

The clock has kept perfect time the last 4 years.

Cheers...

 

[Francois]

I agree that it could be a capacitor problem and that the new caps should be 35Volt.

On mine that capacitors are fine but the 130 Ohm resistor was dead.

 

[Robert Cox]

Actually, on mine, the capacitors may have been OK (I had no real way of testing them - just suspected them) but I replaced them anyway while the clock was out. My resistor had been cooked (the painted code stripes came off with my finger) and the circuit burnt around it. I figured this had happened when the capacitors died. The resistor was fortunately still reading the correct value (otherwise I'd never have known what to replace it with :-( )