Three Pentax K1000s in one week, same exact fault

Last month I had three K1000s come through with the shutter stuck open at 1/1000. All three had the same culprit, a corroded magnet switch under the bottom plate. Took me about 20 minutes each once I stopped chasing the escapement. Anyone else see this pattern or did I just get a bad batch from the same estate sale?

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kim_hart721d ago

Corroded magnet switch makes sense, but the stuck open at 1/1000 part is likely a separate issue. That speed is the only one that uses the magnet release instead of the mechanical escapement. The corrosion probably left the magnet weak or dead, so the curtain never gets released. You likely fixed it by cleaning the switch contacts, not the switch itself. A bad batch from one estate is possible, but I see a lot of these where old batteries leaked inside the bottom plate. Worth checking the battery compartment next time, because acid sneaks down there and eats the switch wiring.