hifi engine

Revox B77 Play, FF, RW function only when buttons held down

I am trying to rehabilitate my B77, which I have owned since buying it new in Germany in about 1980 but have not used in over 20 years. It seems to work properly except that the tape transport will not "lock" into action. Play/Record, Fast Forward, and Rewind all work while the respective buttons are held down, but the transport stops as soon as the button is released. The same happens with both the unit's own buttons and those on the remote control. In addition, the tape counter is at 0000 and does not advance or retreat during operation.

Does anyone have a suggestion, or a recommendation for repair here in the U.S.?

Thanks in advance,