RA117 serial number N0489 (/cont)

The ‘front-end’ of the RA117 differs from that in the RA17L in that there is no 0.5-1MHz pre-selector. Instead there are now two broadband positions; one of which like in the RA17L, the input is terminated in 75R and the other where the input is terminated in 2K2.

As can be seen from the photograph on the left; a previous owner had replaced the old tubular decoupling capacitors. I replaced these with more modern ones.

As previously mentioned, the first VFO is now an EF93. R39 (V5, g2) is increased from 1K to 22K and R41 is now 10K as opposed to 47K. The first mixer is still the trusty E180F (or CV3998).

Again, some of the old tubular capacitors had been replaced … and again I replaced them per-se, in keeping with the rest of the capacitors in the radio.

Finally, VFO1 in the RA117 has an extra bracket attached to the lower front edge. This has two tapped holes (or hank-bushes) for screws which come up from under the chassis. These were missing at the time but I have a large box of miscellaneous screws and it was just a matter of rummaging through it until I found two appropriate UNF threaded screws. I can’t be certain, but this additional bracket may be a way of improving the ‘grounding’ and thus improve the signal-to-noise ratio.

It is a good idea to test the unit at this point since access is non-existent once the radio if fully re-assembled. At this point I noticed that something wasn’t quite right with the tuning of the pre-selector. This turned out be the result of someone fitting the ‘stop mechanism plate’ on the variable capacitor upside down and was restricting the HF end of the  AE tune control.