hifi engine

Service manual for Technics SH-8046 please?

I have a Technics SH-8046 that will not hold its preset memory, this should be a very simple fault to repair but as there is no sign of a buttn cell battery it is being done using one of many capacitors.

Any help greatly appreciated. I have checked the SH-8066 service manual but it seems a very different unit to this one.

Kind regards,