[Penthode]

Making further progress. Hoping to within the next couple of weeks power up the chassis minus the CRT.

Replaced most of of the paper capacitors. This chassis takes a lot and awaiting an order from Digikey to complete.

Reforming the can electrolytics: all coming up with low leakage after a few hours feeding a 10mA current limited supply. It looks like this set has sat dormant for the past 40 to 50 years as all the earlier replacement capacitors are quite old themselves now. Despite that, the electrolytics came back from almost a dead short to holding full rated voltage with less than 100uA leakage in just three hours. Not bad. We will see how they fare.

The design uses early cartridge electrolytics for DC coupling in the chroma stages and despite coming back with low leakage, I am substituting new ones. The 4uF 450v units are on order from Digikey.

My power switch solution entailed installing a 120vac relay. The relay contacts are rated at 25A at 120vac. It was interesting to note the original Centralab 5A switch on the volume control physical form factor matches the standard 3A switches. I can picture in my mind RCA Victor engineers calling the Centralab engineers in around 1953 asking them to beef up the specs from 3A to 5A and the incredulous Centralab people replying "What the heck are you powering?"

Anyhow, the photo below show the fitment. The replacement 3A switch on the volume control now only has to energize the relay.

I shall be substituting 3A silicon diodes for the old Federal selenium rectifiers. And still considering various solutions for the super hot voltage dropping resistors.

The KRK12 tuner unit has been fully dismantled, cleaned and lubricated and is ready to re attach to the main chassis.