Thanks burt007 but what to do if I don't know which is the 'clock' button 8-O ... As I wrote the lettering are eroded (almost not visible), unfortunately.
I also know this usual method what you described, tried, but there are too many (button) variations.
In addition, would have to tune the radio stations, store and recall them, the band select ...
Yes, the user manual would help, but the service manual can also come in handy later.
Before I wrote here, of course I looked everywhere on the net, but without any result.
Thanks anyway ...