1941 Cadillac Clock

[C Gorgas]

The 1941 Cadillac clock has been rebuilt using quartz mechanism to make it run. It keeps very good time until I start the engine and then takes about 3 minutes or less time to rotate one complete hour. There is apparently some interference involving the engine running. I am at a loss. I have had the clock on the work bench using a battery charger and it works just fine as well. Is there something I might place in the hot side of the line that would counter the interference? Much like what one puts in the line to negate radio interference. Chet 25441   

[Bobby B]

Chet,
What's the voltage at the clock source with the car running, and the car dormant? Did the quartz movement specify that positive and negative have to be adhered to?  Can the leads be swapped? If it runs on the bench, it should run in your car. Something isn't hooked up correctly.  Time Flies when you're having Fun....
                                                        Bobby

[Bob Schuman]

Chet,

I had a similar problem with a quartz conversion clock in a 1940 LaSalle. It would keep perfect time, but sometimes after starting the engine it would lose about five minutes, then keep time but five minutes late. The clock had been converted by John Wolf Co. of Willoughby, Ohio. John provided a capacitor that I connected from the clock power terminal to ground, no further problem. I don't know enough about electronics to explain further, so I suggest you talk to whoever converted your clock for help. That car was 12 volts positive ground.  Wolf Co. converted the clock for my present 41, a six volt positive ground car, and it has not needed the capacitor to make it run properly.

Bob Schuman

[bcroe]

Given that your clock only has 2 terminals (not including a pilot
light), there isn't any doubt the problem is with the power
source.  Of course the clock should have continuous power
independent of ignition.  I have seen similar problems with a
factory tach. 

Seems like there are 2 possibilities.  One is, starting the car causes
such a power disruption, it throws off the clock. 

The other is, running the generator system is causing noise pulses
to be fed into the clock power.  A scope would reveal what is happening. 

You could try running the lock leads as directly to the battery as possible,
not sharing any wiring with other (potentially noisy) circuits.  The other
method is add a filter at the clock power input, first guess is around a
1000 ufd cap, carefully observing polarity.  More extensive filtering
could be needed, esp if there is a problem with voltage dropout cranking. 
good luck, Bruce Roe

[C Gorgas]

I really appreciate the comments. I will try what you suggest Bruce and see what happens. The whole thing is strange to me. Chet 25441

[Barry M Wheeler #2189]

I have only scanned the replies, but why are you "hooking up" the quartz clock to the car? All the quartz motors I know of run on a AA battery until it runs down. No "connection" needed. The light should be part of the under dash wiring and have nothing to do with the clock portion mechanism.

[C Gorgas]

I'm not hooking up a "quartz" clock as such. Maybe I did not describe it correctly. The movement inside the clock runs like a quartz clock but requires electricity from the car and in this instance 12 volts. Hope this clarifies somewhat. Chet

[35-709]

And the car has been converted to 12 volts negative ground?

[C Gorgas]

No. it is 6 volt and I have an inverter/converter. Chet

[Paul Phillips]

Probably this is not much different than the radio interference issues from the ignition. A large value capacitor (1000 uf) will help whatever power supply in your converted clock with general voltage fluctuations. If your problem is from higher frequency noise, you need a bypass cap on the power feed to the clock - something like 0.01uf to 0.1uf. Best plan is to do both the 1000uf and a .01uf bypass in parallel.

Paul

[Paul Phillips]

I just disassembled my 41 clock, which decided to quit on the way to this year's GN.  The Jaeger movement is fairly ingenious, creating a magnetic oscillator with the balance wheel - very different from the typical solenoid clock mechanism.  Unfortunately a copper contact whisker failed, where it touches the balance wheel on every cycle - that's a lot of electrical contact switching over the years!  If any of you who did a quartz conversion still have the original Jaeger movement and are willing to part with it, I would love to talk with you, hoping it has a serviceable contact whisker.

Thanks
Paul

[35-709]

How about contacting one of the many outfits that rebuild or convert old clocks.  They may have boxes of old movements lying around, if they haven't discarded them.  Instrument Services   https://www.clocksandgauges.com/    is but one company that I have had experience with.

[C Gorgas]

Just to give all of you an update on my "galloping time" clock. The advice given using a capacitor 1000uf worked; all is normal thanks for everyone's input. Chet 25441

[jackworstell]

Paul....I'm not clear how the 1000uf   and the 0.01uf capacitors are wired into the clock power feed...please clarify.

Jack Worstell       jlwmaster@aol.com

[Paul Phillips]

Jack
The capacitors are connected between the battery power lead and ground at the clock. For the 1000uf, it will be a polarized cap, so orientation is important. An original 1941 car electrical system is positive ground, so the cap's + lead goes to ground and the - to the battery terminal on the clock. The 0.01uf is not polarized, so connect one lead to ground and one to the battery terminal on the clock. If someone has modified the car to 12v negative ground, the cap's + lead would go to the terminal on the clock and the - to ground.

Paul

[jackworstell]

Thanks Paul

Jack