N_Cook wrote:
Does anyone know the voltages on the 3 secondaries
Main deck motor 12V but about 10.5V dc from the supply, nothing wrong with
the ps and nothing wrong with the motor and its regulator. All that is left
is the mains transformer.



Nigel,

For what it's worth, I'm looking at a diagram for an AD-6300U, dated
December 1976. This is a US model, with only a 120V primary. It shows
that the transformer has 3 secondaries, one of which is devoted to the
motor. It has a half wave (single diode) rectifier, D503, and a
1000uf/16V capacitor, C506. It shows the voltage on the cap as 14.5V
it also shows 2 switches, S6 and S7 in parallel between the cap and the
motor, so either switch could power up the motor. Could you have badly
corroded switch contacts that are causing a large voltage drop? What is
the voltage with the motor disconnected? If you are measuring the 10.5V
at the capacitor, then I'd say try replacing the diode and/or capacitor.

Regards,
Tim Schwartz
Bristol Electronics