August 2015: Last month I picked up a couple of very sorry looking RA137As. Both
were incomplete and looked as if they had been stored in a chicken shed! Although
both were missing the rectangular tuning bezel, a quick glance over them convinced
me that I had a good chance of getting a working converter from the two ‘wrecks’.
Using what I took to be the date codes, one was assembled in January 1963 and the
other in June 1964. The older of the two was definitely in a worse state. A large
part of the Perspex tuning cursor was missing and the rotating ‘drum’ was seized.
An interesting point here is that this unit used an unusual drive cord arrangement
for turning the drum where it looks like the drum is spring-
Having decided to use the newer of the two RA137As as the basis for my re-
Unlike the RA17, the RA137 is not complex. It consists of an RF amplifier with a
switchable preselector, a double balanced mixer and a cathode-
RA137 functional block diagram
Despite it’s simplicity, the RA137A proved to be an annoyingly awkward unit to work
on … largely due to the fact that the valves are mounted end-