12-02-2020, 12:12 AM
I previously posted pics of this radio that was given to me in November Finds, post 16 (https://philcoradio.com/phorum/showthread.php?tid=21776). I decided to have a go at it. The radio had had the Selenium rectifier bypassed with a silicone diode without an additional dropping resistor. A couple of caps had been replaced and the radio actually worked quite well. Regardless, I decided to fully recap it and replace a few out of spec resistors. Several of the "Black Beauty" caps were split. Another Chinese yellow radio! I read in Russ's tread on the 1L6 that the filament resistors are rather critical so I replaced all of them as well. The radio came to life with a 50 ohm dropping resistor but that was too much. 25 ohms brought the filament voltage to just over 1.4 volts and the B+ right at spec. All bands work all across the the band. There are a lot of alignment controls to adjust and alignment went well with the tracking quite close. Sensitivity and selectivity seem very good. This is my first experience with these 1 volt tubes and I'm quite surprised at how well they are working even though they produce almost no heat. Only the output tube gets very slightly warm. Sound is, perhaps, as good as can be expected from a 4" speaker outside of its cabinet. Volume is good.
The volume control was worthless as most of the carbon track was gone. probably cleaned too many times with the wrong cleaner. It's a 1 meg control with a DPST power switch. I didn't have patience to order one, so I decided to try my hand at a repair. I had a 500K pot (new) that I took the resistive element out of. With some judicious re-shaping, sanding, drilling and riveting, I was able to transplant the element, hoping that the 500K would work in place of the 1 meg. It does and the control is now quiet and smooth.
Now to see what I can do with the portable cabinet. I heard black shoe polish works quite well.
The volume control was worthless as most of the carbon track was gone. probably cleaned too many times with the wrong cleaner. It's a 1 meg control with a DPST power switch. I didn't have patience to order one, so I decided to try my hand at a repair. I had a 500K pot (new) that I took the resistive element out of. With some judicious re-shaping, sanding, drilling and riveting, I was able to transplant the element, hoping that the 500K would work in place of the 1 meg. It does and the control is now quiet and smooth.
Now to see what I can do with the portable cabinet. I heard black shoe polish works quite well.