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Garage Talk / GENTLEMEN – I AM CONFUSED, NEED YOUR INSIGHT
« on: February 16, 2025, 05:26:29 PM »
Although, not a Camaro topic, this is related to our Camaros in a general sense.
The following involves the dash clock in my ’66 Chevelle Malibu and the fact that my knowledge of the electrical side of things is not my strong suit. A little background….
Originally, the clock in my Chevelle had an auto-wind mechanical movement manufactured by Westclocx. It had constant +12v dc connected to it to provide power to the coils that were part of the auto-wind function.
The clock quit working a long time ago and in 2000, while I had the dash completely disassembled, I removed the clock from the instrument cluster and sent it to a vendor to be converted to a quartz movement. Afterwards, the clock worked well until about 5 years ago when the hour hand quit moving.
This past December I began a series of “punch list” items on the Chevelle which included removing the A/C Heater control unit, cleaning and upgrading the slide levers from the original pot metal to stamped steel levers, lubricating the Bowden cables, etc. With the AC/Heater control unit out of the way I also now had additional access to remove the clock for servicing.
In early December 2025, I shipped the clock to a well-known auto instrument servicing/repair company in the Rockford, IL area. It was returned to me mid-January with instructions to bench test the clock prior to reinstalling and to ensure that the +12v DC power supply to the clock has a 1-amp fuse in the circuit. I had planned on bench testing anyway and so far, so good.
The clock ran on the bench for 3 days without issue. I then reinstalled the clock in the car, and it ran for approximately 7 hours before stopping. Go figure. I tapped the back of the clock, and it ran again for a few minutes and then stopped. I called the repair shop, explained the situation and even sent them a short video showing the clock running after being reinstalled in the car. I also told them that I had bench tested the clock for 3 days prior to reinstalling it in the car using the 12v DC battery shown in the attached picture. They said for me to send the clock back to them, which I did. I just received it back on 15 Jan. It currently is being tested, connected to its constant +12v DC power source in the car, prior to to re-installing it in the dash sometime next week.
It was extremely difficult to get any meaningful response from the vendor after I sent the clock back to them. For example, when questioned as to what was wrong with the clock, all I got back was ”the gears needed adjusting” which didn’t tell me very much.
Now, here is where my confusion begins………
After I told the vendor that I had bench tested the clock for 3 days prior to reinstalling it in the car using a Duracell 12v DC battery, the vendor responded, “ IF YOU TEST THE CLOCK OUTSIDE OF THE CAR, PLEASE BE SURE TO USE A 12V CAR BATTERY PER OUR TECHNICIANS”. I asked for clarification and the response was that it is due to the “battery’s capacity” and that “in the past they had had a clock stop during a bench test when using something other than a car battery”.
My confusion is that in my mind, this quartz clock looks out to the world through its +12v DC and case ground connections and asks for ANY +12v DC source that can supply something on the order of 200 mA to the clock. (I’m not sure exactly what the milliamp draw is, but remember, this is a 1 amp fused power supply, and I would be surprised if the current draw is much more than 200 mA).
Any ideas why the vendor would insist on using a car battery to bench test the clock and reference the capacity of the battery as being the reason?
The vendor is a very reputable provider of repair services for automotive clock, speedometer, tachometer, fuel gauges, oil gauges, battery gauges, amp gauges, temperature gauges, gas tank sending, etc. and has been around since 1979 with a significant business presence. They are not a mom-and-pop garage operation.
Consequently, I must be missing something, but I can’t figure out what.
Any and all feedback would be appreciated.
The following involves the dash clock in my ’66 Chevelle Malibu and the fact that my knowledge of the electrical side of things is not my strong suit. A little background….
Originally, the clock in my Chevelle had an auto-wind mechanical movement manufactured by Westclocx. It had constant +12v dc connected to it to provide power to the coils that were part of the auto-wind function.
The clock quit working a long time ago and in 2000, while I had the dash completely disassembled, I removed the clock from the instrument cluster and sent it to a vendor to be converted to a quartz movement. Afterwards, the clock worked well until about 5 years ago when the hour hand quit moving.
This past December I began a series of “punch list” items on the Chevelle which included removing the A/C Heater control unit, cleaning and upgrading the slide levers from the original pot metal to stamped steel levers, lubricating the Bowden cables, etc. With the AC/Heater control unit out of the way I also now had additional access to remove the clock for servicing.
In early December 2025, I shipped the clock to a well-known auto instrument servicing/repair company in the Rockford, IL area. It was returned to me mid-January with instructions to bench test the clock prior to reinstalling and to ensure that the +12v DC power supply to the clock has a 1-amp fuse in the circuit. I had planned on bench testing anyway and so far, so good.
The clock ran on the bench for 3 days without issue. I then reinstalled the clock in the car, and it ran for approximately 7 hours before stopping. Go figure. I tapped the back of the clock, and it ran again for a few minutes and then stopped. I called the repair shop, explained the situation and even sent them a short video showing the clock running after being reinstalled in the car. I also told them that I had bench tested the clock for 3 days prior to reinstalling it in the car using the 12v DC battery shown in the attached picture. They said for me to send the clock back to them, which I did. I just received it back on 15 Jan. It currently is being tested, connected to its constant +12v DC power source in the car, prior to to re-installing it in the dash sometime next week.
It was extremely difficult to get any meaningful response from the vendor after I sent the clock back to them. For example, when questioned as to what was wrong with the clock, all I got back was ”the gears needed adjusting” which didn’t tell me very much.
Now, here is where my confusion begins………
After I told the vendor that I had bench tested the clock for 3 days prior to reinstalling it in the car using a Duracell 12v DC battery, the vendor responded, “ IF YOU TEST THE CLOCK OUTSIDE OF THE CAR, PLEASE BE SURE TO USE A 12V CAR BATTERY PER OUR TECHNICIANS”. I asked for clarification and the response was that it is due to the “battery’s capacity” and that “in the past they had had a clock stop during a bench test when using something other than a car battery”.
My confusion is that in my mind, this quartz clock looks out to the world through its +12v DC and case ground connections and asks for ANY +12v DC source that can supply something on the order of 200 mA to the clock. (I’m not sure exactly what the milliamp draw is, but remember, this is a 1 amp fused power supply, and I would be surprised if the current draw is much more than 200 mA).
Any ideas why the vendor would insist on using a car battery to bench test the clock and reference the capacity of the battery as being the reason?
The vendor is a very reputable provider of repair services for automotive clock, speedometer, tachometer, fuel gauges, oil gauges, battery gauges, amp gauges, temperature gauges, gas tank sending, etc. and has been around since 1979 with a significant business presence. They are not a mom-and-pop garage operation.
Consequently, I must be missing something, but I can’t figure out what.
Any and all feedback would be appreciated.