In the previous installment, I had finished rebuilding the RF/converter section which was taken from a 37-670. I opened this workbench session by going over the connections and making sure they matched the wiring diagram I had drawn for this section (see Part 9 for details).

Upon making sure everything was connected as it should be, I pulled out the main RF unit and first installed this RF/converter section, and then the antenna section. I carefully installed the switch shaft before tightening the bolts which hold the RF/converter and antenna sections in place. All seemed well.

Next, I did a test run of the switching action by carefully turning the switch shaft through all five positions. Much to my relief, the switching action was smooth with no hints of any trouble or resistance. Of course when all three sections are in place it is not possible to clearly see every wafer, but from the wafers I could see, I did not see any signs of any bent contacts.

With that test out of the way, I soldered the wires from underneath to their respective positions under the tuning condenser, added two more wires which connect from the oscillator section to the oscillator control circuitry, and reattached the sides. The final product is shown below.

I had been thinking about how to go about testing this unit. I have decided not to test it inside the 38-690 itself to avoid any damage to it in case I made any mistakes in wiring. Instead, since I have a clean, restorable 37-116 chassis, I am going to fix it up just enough to be able to use it as a test bed for this rebuilt RF unit, piping the audio from the volume control into my workbench Lepai amplifier or into my homemade signal tracer (formerly a Panasonic portable AM/FM radio, modified for use as a simple signal tracer). I do not have a 37-116 speaker, so this way I will not need to use any of the audio tubes in the chassis.

Next time, we will dig into that 37-116 chassis and get it ready to use for trying out the rebuilt RF unit.