VCR works fine in play and record as long as the head drum gets up to speed by flicking by finger while the tape is lacing. So assuming nothing wrong with the bearing , normal free movement when unpowered. Sometimes drops out in play or record on hitting ruffled tape so a motor problem.
VCR is Osaki VCR 34H , no knowledge, so i don't know if correct ps voltages for a start
3 lines from the TA2620D driver IC to the coils and further ends of each are joined together but not returned to anywhere so presumably 3 phase. There are 12 coils from these 3 lines mounted on the iron frame with 12 'poles' The surrounding magnet rotor part has 8 North poles, 8 South poles. On pcb 3 hall effect sensors presumably for relative phase monitoring these magnets and a separate magnet pip on the outside of the rotor and 1 hall effect sensor for 1 pulse per rev. But what is the PCB track/coil ? etched on the board under the rotor. Not connected to anything else on the motor sub-board and just copper track as far as I can see, roughly like Beta vcr tape path, one track runs right round circularly and returns 'circularly' with 24 castellations pattern. What and how is it sensing or sending anything? and what's its function ?I have another matching salvaged multimagnet rotor so can eliminate magnetisation loss as reason
Any tips for 1 or 2 channel scope for monitoring driver IC, does not run hot and unpowered 'diode' DVM checks seem reasonable.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
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