Circa '47 Pilot model T-601 "pilotuner" FM tuner

[radiotvnut]

Here's a Pilot FM tuner from about 1947 that I recently obtained. It's purpose was to plug into the phono input of AM receivers, allowing them to receive the new FM broadcast band of 88-108 MC. This tuner also has a phono input so that you won't lose phono operation when used with radio/record player combinations. When the tuner is off, the phonograph is switched into circuit. When the tuner is on, the phonograph input is switched out and the output of the tuner is switched in the circuit. This one had a bad filter can, a shorted .015 uf paper capacitor that was killing B+ to the front end, and I had to replace the selenium rectifier because B+ voltage was dropping down after it warmed up. This model uses a power transformer with the following tubes: 6BA6 - RF amp, 6BE6 - oscillator/mixer, 6BA6 - 1st IF amp, 6BA6 - 2nd IF amp, and 6AL5 - detector. I also replaced the other paper capacitors and the Micabomb line bypass capacitor was very leaky and about to pop. This unit works well for what it is; but, it does not like to be plugged into AC/DC radios. When I tried it on such a radio, the hum was so bad and the audio was so garbled that I couldn't listen to it (reversing the plug of the radio did not help). However, plugging the radio or the tuner into an isolation transformer cleared up the issue. This will probably only be used with radios that contain a power transformer; so, it's no big deal.

Here is the youtube video on it: https://www.youtube.com/watch?v=n3w6xUSuIXA