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Model 90 - poor sensitivity
#1

I have a Model 90 lowboy that until recently was working very well. It was recapped, retubed, and aligned, etc. - the extent of my technical expertise. One day it became almost totally deaf, receiving only the one, close station. I don't see anything obviously wrong. What is odd is if I connect a jumper from the antenna connection to the oscillator tube anode (I think that's the tube), it receives pretty well. Probably not as good as it should if the earlier stages worked, but decent reception. While this "fix" solves my issue, my OCD wants to make it correct. Any suggestions as to where to look? My concern is one of coils failed and that's above my pay grade, plus the challenge of rewinding or finding a replacement.

Any advice would be appreciated.
#2

Which version of the model 90 is it? Are all the heaters lit?

When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!

Terry
#3

It’s the version with the single 47 tube in the audio amp. Heater meaning filaments, yes.
#4

Sounds like you might have an open antenna coil. Check both the primary and secondary windings for continuity.
#5

I will take a look at that. Thank you.




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