Corvette clock restoration:

[vettte_wings]

I have the original clock in a 77 Vette that after the battery has been disconnected it still runs for about three minutes.

I never heard of a clock being magnetized as I was told, but does the Console Gauge Printed Circuit board have anything to do with the clock still running after the battery disconnected?

Reason being is that I have a dead battery after three days. The battery was tested fine twice; I did the test light troubleshooting and found that the lighter, interior light and the clock were on the same circuit.

I’m not sure how much amps the circuit is suppose to be or even how to test this, but before I pull the clock out for repair I need some troubleshooting tips that someone has experienced on this.

Actually I'm putting blame on the clock because it still runs after the battery has been disconnected and think it’s causing the battery drain.

Since I have the carpet out the lighter will be next to be disconnected and another test will be done.

Is there a plug for the interior light that disconnects the interior lighting so I can troubleshoot that?

Thanks...............

 

[JohnZ]

Most older car clocks are mechanical, but are electrically wound, which is why it keeps working for a while after you disconnect the battery. It's unlikely that the clock is causing your battery drain, as the rewind coil draws far less than one amp, only when it's triggered by the points for the clock spring. If the points were stuck together, the coil would have fried by now and the clock wouldn't work at all.

I don't have a '77 wiring diagram, but the clock and courtesy lights are normally on the same fuse; pull that fuse, connect the battery, and if it doesn't run down, you know it's something else causing the drain. The best way is to remove the negative battery cable, then insert a digital VOM set on "Amps" between the battery terminal and the cable terminal - if something is causing a steady drain, it will show on the display. Then start pulling fuses one at a time - when you pull one and the drain stops, you know it's something on that fuse's circuit that's the culprit; then the fun starts, trying to isolate which device it is.

 

[SLICKMAN]

I agree with JohnZ, its not the clock...

 

[vettte_wings]

I’m going to do that troubleshooting like you suggested JohnZ but there is one thing I like to know more about is a digital VOM.

I was looking at the digital multimeter Fluke 110, 111 and 112 Series True rms.

I found this to be an expensive unit but I like the way this unit is set up especially with the backlighting on the 112.

Just curious what kind of multimeter do you use?

I not familiar with using one of these “yet”, but I’m ready to invest in one and learn it capabilities.

Do you have any suggestions on a reasonably priced unit I can purchase that will be versatile between the auto and home or do they do both?

I'm still on the hunt for a multimeter on the net.

Thanks again guys……………..

 

[JohnZ]

Fluke is the best there is - I use a Craftsman auto-ranging digital VOM - works on everything, even has a thermocouple function and a temperature probe, not very pricey.

 

[GaryS]

Not to dispute JohnZ but if your clock is the electro-mechanical kind as described, there are more than enough reports out there of clocks killing batteries. If the clock points malfunction and "weld" themselves shut, you will have a constant drain on the battery, perhaps even enough to cause the battery to die in three days. The bigger hazard MAY be an electrical fire.

I would use a mulitmeter, as others have suggested to check for a draw in your system. If that test comes up negative, then I would pull your clock for a little testing.

Once you pull the clock out, open it up. A simple test can be done on the clock. Wait for it to wind down and, using a 12V battery charger, touch the terminals of the clock with the electrodes from the battery charger. You should see the rewind mechanism work then the points should open. If your points stay closed, then they MAY be the culprit.

Gary