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We see that the base is indeed > 5V, but collector and emitter of Q2 are both way above 3.3V. This indicates that the 3.3V zener has given up. After replacing the zener we got back to the usual errors:
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have a proper signal when the test runs:
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Light blue is the signal on pin 6 E7, yellow is the signal on pin 4.
After this, and after messing with some floppies I got this:
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It looks like an entire pass tested OK 
During the test I could see the head moving; first track by track, after that reading random tracks… This part seems to be OK
Running the test with both drives filled with a properly filled floppy shows:
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