B780 does not retain tuner presets when unit is unplugged

[Boogeydog]

Good Day,
I recently completed a rebuild of a B780 but am left with one issue. The tuner presets are lost when the unit is unplugged. The charging circuit is OK (producing just under 6 volts with the batteries removed) and the batteries are producing the correct voltage. The electrolytics have been replaced on the microprocessor board. Other than this the unit is really good. Any suggestions are appreciated!
Cheers,

[Boogeydog]

Rethinking this. I had a lot of IC's that were badly corroded. Had to replace a few that were missing pins. Does anyone know what IC's are specifically for channel memory?

[mike9000]

Hi,

reading the service manual, imo, the "channel memory" is within IC1 (microprocessor).

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[Boogeydog]

That's bad. Can't get a replacement for that one. Many thanks for taking the time.