The RRBM5 has the same weakness than is RS-560 brother.
Both uses a clever rotary discs mechanism to setup all the required band parameters.
This can be seen on the following picture:
Small fingers are used to connect those discs to the receiver electronic:
All the discs are tied together using a square axle made of plastic:
But with the time, this axle get used:
Two solutions can be used to solve that issue:
- Dismount the axle ends in order to swap them. This will work as the discs emplacement is not symetrical,
- Add a small piece of paper in order compensate for the thickness.
While trying to repair the wonderful receiver, I found its manufacturing date - January 1973 - on the quality service stamp:
Here LC filters are used instead of mechanical or crystal models making this receiver a real pleasure to listen to:
And the front head stage is coil fine tuned:
Fine tuning is motorized on the RRBM5 version which keeps the RS560 dial mechanism:
A extender board as been made in order to repair the synthetizer: