There is no way all of the TTL chips would be powered by a small reed relay.
That doesn't make any sense.

The K1 (Motor control) Relay coil is connected to +5VD on one end,
and an active low MOTOR signal on the other end (which drives the relay coil).

The relay contacts connect to the cassette jack.

If your tech thinks all of the TTL logic on the main board is being powered
through a small reed relay, you may want to find someone else to work on the synth.

Just sayin'

Bob