10auc complete balance or flyspring required

Hi guys

Newbie here so please be kind :). I'm working on a nice 1950 duo wind. The movement has seen better days but I don't want to give up on it. It has a lovely case, face and hands. The flyspring is shot so searching for a replacement. Alternatively a complete balance would do. I'm pretty new to this so not sure of what alternatives could be used. I've heard mention of ETA and Felsa movements which are the same. Advice welcome. David

1955mercury's picture
Posted November 17, 2014 - 12:47pm

Hi David. By flyspring, I'm speculating you mean hair spring, (the delicate torsion coil spring on the balance wheel). The 9AB, 10AU, and 10AUC are all interchangeable. The part # is 61A. This movement has a breguet hair spring. Dashto.org has them for $6 + shipping. It will be listed as being for the 9AB because all Bulova parts are listed for the movements in numerical order. If you would rather have a complete balance, the same movements listed above all have the same balance assemblies, but I don't know where you can get one right at the moment. The part # for the complete assembly will be part #55 and will be labeled for a 9AB movement. Generally it's cheaper, if you're patient, to find a donor movement with a good balance assembly rather than buying a NOS one. Then you have a lot of other spare parts for your movement should the need arise. Someone else on here may have the part you're needing.

Posted November 17, 2014 - 10:22pm

Hi 1955Mecury, yes, as soon as I'd pressed save I realised the error. Sorry about that. Your info is a Godsend. I'm still trying to figure out what's what. I suspect I should have started on something easier but it's a beautiful watch and I've learned so much already - mostly about not what to do though at this stage. I got a lead elsewhere that told me the Felsa 700 (and possibly close variants) might also be good for parts so armed with your guidance and the Felsa info I'm on the lookout now. Ideally I'd like the full balance assembly as I'm terrified of damaging the hairspring but if needs be, I'll try for the hairspring and go for it. I'd love to see this baby come back to life.

Once again, thank you for taking the time to answer. Much appreciated. David

Posted November 20, 2014 - 8:09pm

David, PM me, I have a running movement I will sell you for $35.00 if interested.