The Cessna 120-140 Association Forum

What is this hole for on the back? I don't have one at hand right now to get a light on it.

I've got one that will run if I give it a tiny bit of twist pressure on the adjustment knob. Otherwise with 12V it doesn't run. Im guessing it's just enough gummed up internals that the motor won't scoot.

Most of those old clocks are actually wind up mechanisms with a little electric solenoid that winds it every time it unwinds enough to close a set of contacts.

Not sure about the hole, maybe an adjustment screw?

Easy to get the wind-up clock from eBay or new ones from Waltham Clock. Very satisfying bit of mechanical kit.

Thank you both. I agree mechanical is more satisfying. I went with a Wakmann. I did not know about Waltham - great find!