So my new (to me) 1965 Seamaster 600 is running a bit fast, I’ve noticed. Like >minute per day. (I haven’t actually timed it out but it’s noticeable.) Seller from the UK described it as keeping superb time, and I’m wondering, after reading through many posts on this site, if it could have gotten magnetized at some point during its long migration from England to Maryland. I may take it to the local repair shop tomorrow to have them demag it, which I’m guessing they’ll do cheaply and quickly while I wait. Just wondering if you all have any other ideas as to what might be culprit here. Let’s assume the seller (who both over email and phone struck me as a very honest person) was telling the truth. If it turns out it needs something more—regulation, I guess?—what can I expect to pay and who should I trust to handle it? Thanks! Again!
I think your local repair shop will have some ideas about why it would be running so fast if it was previously keeping good time, and they can inspect it. Aside from magnetization, common culprits are oil or foreign matter in the hairspring, or something that has become loose and is interfering with the balance. If it was truly keeping good time before, it wouldn't make sense to fix a 1 minute per day error by regulating it.