Clock question

[Jim Yergin]

About seven years ago I was given an original dash clock for my '41 P12. At that time I sent it out to be overhauled but I never got around to hooking it up. This past weekend I connected the power to it but it would not run. After checking this forum for past postings on clocks I removed the clock from the car and took it apart. I cleaned and lubricated the mechanism and got it to run. However it would only do so with a 7.5 amp or higher fuse. The specified 2 amp and even a 3 amp fuse will burn out as soon as the contacts connected. In addition, when the contacts made contact there would very often be a loud buzzing sound and visible arcing at the points. I cleaned the points and the noise and arcing stopped. Can anybody tell me why it is pulling more amperage then it is supposd to? Do I need to repair some thing or do I resign myself to just having the correct time twice a day?

Thanks.

Jim Yergin

[Plymouthy Adams]

so how much current are you pulling..are you still 6 volt on your car...I would check the mechanizm for excessive drag on the pivot or incorrect tesnsion on the spring. (maybe wrong spring or incorrect spring position/fastening)..the coils should immediately energize and upon closing the plate against the magnetic coil, wind and self disconnect the contact points...

[Jim Yergin]

Just in case this information might help someone, I thought I would update this thread. I found an article in an old issue of Skinned Knuckles magazine (May 1992) on the repair of automobile clocks. The article recommended installing a diode to eliminate arcing at the contact points. It calls for a 1N4004 or 1N5404 diode to be wired across the contact points with the cathode (-) end of the diode connected to the (+) terminal. I bought a 1N4004 diode at Radio Shack and installed it in my clock. Solved my problem and the clock now works without the arcing, gummed up contact points, or blowing the fuse.

Jim Yergin

[busycoupe]

The same kind of diodes are used on the coils in pinball games, and for the same reason. When the contacts open, the coil releases a charge in the opposite direction of the current flow. That is why the neg. diode contact is connected to the pos. connection on the coil. The diode blocks this back-current. I have fixed many pinball games, but it never occurred to me to use a diode on my car clock. Thanks!