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Old 22nd Jan 2022, 7:32 pm   #2
ms660
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Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 12,283
Default Re: Testing before replacing Reel Motor A77 Mk3/4

So far as I can make out from the schematic, with the reel motors switch in the on position, the tape threaded up so the end of tape sensor is defeated and the fast forward function selected then D13 & D14 should be connected through to the 105V connection on the secondary of the mains transformer, D15 should be connected through to the 0V connection and D16 should be connected through to the 0V connection via the motor capacitor, so with the conditions above and no motor connected the AC Voltage between D15 and D13 or D14 is likely to be a bit higher than 105 Volts AC with no motor connected.

With play selected D13 & D14 should be connected through to either the 55V or the 42V connection on the secondary of the transformer depending on the reel size setting, again that AC voltage could be a bit higher with no motor connected.

Lawrence.
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