Vintage Radio Restoration: Part 2

Well the filter caps have arrived from Element 14 and have been fitted. I’m still waiting on the 5 watt 1k ohm dropper resistor to arrive but have come up with a temporary fix by stringing some resistors I had in my junk box together. This allowed for some testing as I cannot get anything out of it, no stations just some minor hum with the volume at maximum.

A quick probe around with a volt meter showed the audio stage to be in perfect condition and I ended up connecting an audio source to the EBC81 tube and got good quality audio out from the speaker. Volume and tone pots test fine with no static noise when adjusted. Moving back to the IF amp which is an EF89 pentode. Testing suggested that this tube is doing its job just fine so I don’t have any reason to suspect any faults with it. Moving back to the input mixer/Local oscillator tube which is an ECH81. Testing the anode voltage in the triode stage showed normal operation as did placing another AM radio nearby and tuning across the band until the static vanished. At this point in time I suspect the heptode stage in the ECH81 is at fault although without a tube tester or signal generator I cannot test this theory. I have ordered a new ECH81 from Tube Depot to try and see if it kicks the radio back into life.

Well stay tuned for more because I haven’t finished with this radio yet.

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