Hi all, I have a question to ask about mechanical accuracy, not sure if this is the correct place..
I recently purchased a Marathon General Purpose Mechanical Benrus Limited Edition.
However , recently I realised it has been gaining some serious time. We are not talking about seconds here, we are talking about minutes. A quick check it has gained 4 minutes in just 12 hours. I will continue to monitor it and check for 24 hours. What Im asking is if this is normal for a vintage ETA 2801 Benrus? According to the story Marathon reused these 600 NOS Benrus ETA 2801 movement found in a vault post war. I am not super concerned with accuracy and am aware of limitations of a mechanical watch accuracy but it affects me if it is off by minutes. I just bought this a few weeks ago and really dont wish to send it for repair

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Sorry if all these sound noobish, new to the hobby!
Anyone know of a demagnetise place near the north? Can just walk in with any brand and ask for demag?