Clocks really aren't my bag, radios are, but I've taken apart an original '70 Chevelle Malibu clock and a '65 Ford Galaxie clock and misc. and worked on them.
The units were "all" made by General Time Corp. The outside case may say "BORG" or something else, but I believe all were made by General Time.
Not a really good design...
But what do expect for 30+ years ago.
The #1 thing I see is fryed coils.
#2 thing I see is jammed main springs.
#3 is corrosion.
All problems are sort of related in a way.
Here's how they work (rather how they are suppose to work
)
The mainspring just like in the 'ol days in the old wristwatches you had to wind, were wound up tight. They'd slowly unwind causing the gearing to turn with ran the clock.
There's a little "escape" wheel that controls the rate of release and causes it to "tick" at regular intervals.
So what happens when the mainspring unravels all the way. Well duh, no one's there to wind it! Except for 12 Volts!
There's a little contact mounted on a pivot on the same rod the mainspring is wound around. When it unwinds, the contact slowly reaches a post with another contact.
Zzzzzap! the 2 contacts complete an electrical connection that sends 12 volts to the coils that electromagnetically "kick" a tiny lever that sends the mainspring winding back with fury. And the whole thing starts all over again. (happens about every 2-3minutes)...
Here's the bad...
These units were dust magnets, they also had very little lubrication. Things froze-up especially the mainspring assembly.
But before that happens the contacts get very pitted, with electicity arcing between them all the time (makes a bad connection).
Why do you think you have to change points in a distributor!
But the killer is the fryed coils. Why do they frey you say?
Well if a car is not used for a long time, the batter slowly depletes, or if someone gives someone else a jumpstart it can send a surge or drain in the system.
When a battery slowly dies the voltage goes down, but the capacity is still strong.
For example when the contacts close in the clock, the 5 volts in the dead battery is not enough to "kick" the works, so it stays connected to electricity, but the battery still has energy to frey the clock coils. Slowly cooks them. Jumpstarting can have a similar effect.
Steve S. has a great idea after rebuilding the vintage clocks. Install a diode across the contacts to prevent electrical arcing.
Steve-please fill us in again
Here's my tip that I read quite a while ago.
Install a 1 or 2 amp quick blow fuse in line with the clock wire that goes to the battery. If there is a surge or a draw, the fuse will hopefully blow and save the precious coil windings.
Hope this helps.
Joe
(creator of Team Chevelle's Radio pages coming soon)
What the hell am I doing still answering clock questions?
Just kidding.
Someday I'll post pics on the 'net what the insides look like of a Chevelle clock.
