I recently serviced this 1960's Omega Seamaster calibre 562 for a ClockSavant customer. He purchased the watch from a local vintage watch store where the owner stated the watch was running well. After purchase it never ran properly and each time he took it back, they charged him money to "service" or repair it to get it running again. Soon thereafter it failed again. Frustrated, the customer did more research and sent the watch to me. Let's review highlights of its proper servicing. First, while clean on the outside, the inside (the movement) was one of the dirtiest I've serviced-- I believe I found some kind of fungus growing deep inside the movement. As I disassembled it, I noted the underside of the balance cock (see red circle) had scratched-out raised areas. Sometimes the underside of the cock is "pricked" at the factory or by a past watchmaker to slightly raise or lower its height to fit the main plate. This type of customization is a perfect example of why simply swapping parts is often not the simple answer. What we see here is that someone either "undid" something they tried, or this balance cock came from another watch. Moving forward, after thoroughly cleaning multiple times by-hand and with the most appropriate strongest chemicals and by machine, I assured it was 100% clean under magnification. I then began reassembly, adjustment, and the rest of the work of full servicing. During this phase, I encountered bizarre timekeeping and reliability issues traced, after some time spent diagnosing-- you guessed it-- back to the balance and balance cock. The relative height and angle of the balance cock required considerable difficult-to-discern adjustment to properly fit this watch. After identifying optimal adjustments and performing them, the timekeeping issue was resolved. Servicing was completed and it is now a beautiful, clean, and nicely running vintage Omega Seamaster once again.