?? I cannot imagine how a defective magnet might drain the battery.
Maybe the magnet circuit, i.e. the electronics that sends a pulse of current into the magnet winding to cancel (momentarily) the permanent magnetization. Maybe if the the electronics is defective and energizes the col continuously? Maybe, maybe...
In all cases, not the magnet itself. So do not waste money.
Read the troubleshooting manual mentioned in this post, and perform the tests, measurements.
https://phsc.ca/camera/research/about-john-craig/repair-manuals/ "These repair manuals are the efforts of the late John Craig whose widow generously donated them to the PHSC in DVD/CD form. The manuals have been graciously transferred from disk to website as pdf files by Jeri Danyleyko."...
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