Kenwood KRF-V5560 memory retention problems

[capslock]

I have above receiver, and while it usually runs fine, it will occasionally forget all its settings or even worse, suddely stop while playing and foul up all its settings.

I suspect something is wrong with the µC or its backup capacitor.

The service manual is available for free download at www.eserviceinfo.com, search for Kenwood and KRF-V.

The manual states on the very first page that all settings will be lost if the power cord is disconnected for more than three days. So I assume the controller chip uses a backup capacitor rather than a flash memory. However, in the schematics, I cannot find anything that looks remotely like one of those 0.1F Gold Cap thingies.

Any ideas?

Thanks