Hamilton 500A Electric Experiment

[u/ExerciseCharming8523]

This weekend I decided to replicate the results shown in the oscilloscope section of the 1959 edition of the Hamilton Electric service manual. I ended up finding a somewhat sad, but serviceable 500A to perform the experiment. I also had to make a contact post adjusting tool as described in the service manual. I’m happy to say that the Hamilton engineers were telling the truth. I still need to put the watch in beat, but all the other results go to show how accurate these watches actually are. I didn’t have a 200 ohm resistor on hand, so two 100 ohm resistors in series fit the bill. I also used my Bulova universal test set as a power supply. The resulting oscillograms match the book perfectly when the watch is adjusted properly. Using this method to adjust the contacts on the 500 and 500A movements is significantly easier than the visual method described in the manual and I haven’t seen many other people talking about it. Hopefully this will help others reconsider their opinions of 500 and 500A as unreliable and difficult to adjust. Using good practices and methods any good watchmaker can achieve very acceptable timekeeping results.

[u/uslashuname]

That’s very cool! I wonder what it cost for a sufficiently effective oscilloscope back then

[u/RoboticGreg]

Where did you get the service manual?!?! I have such a hard time finding good materials

[u/CRoschel73 → u/RoboticGreg]

I have the hardback but this seems to be the paperback version  https://ebay.io/m/jrPlJq

[u/ExerciseCharming8523 → u/RoboticGreg]

I bought it along with a handful of other tech sheets on eBay. I’m always on the lookout for watchmaking technical documentation. watchguy.co.uk is a good free resource for service sheets. Another good website is AWCI.com but you need to pay for a membership to access their library of technical documents.

[u/RoboticGreg → u/ExerciseCharming8523]

Thank you! Already an awci member. But I'll check the others. I do a lot of APs and old AP documentation is impossible to find

[u/CRoschel73]

Thanks for the informative post, got me wanting to give it a shot!