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Adding a coating every 5 minutes gets us this:
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Next step is to put a 1K resistor in parallel with the 200ohm resistor to increase the write current:
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After reinstalling the tape drive the capstan moves the tape, but sadly enough doing an fdf 0 will report an error 43. I also tried rew, but that was a bad plan: the drive did not see BOT and wound the tape off the wheel. Rik had warned me for that and of course he was right 
The unit makes a terrible sound while moving the tape, so clearly something is still amiss…