Motorola 77X-M22

[bandersen]

I could resist hitting the $39 BIN on this blonde AM/FM Motorola circa 1948.





It uses a variable cap for AM and three variable inductors for FM.


It's been partially recapped in the recent past judging by the caps used. It works fine on AM but only got sound for one brief instance on FM. Wonder why they didn't replace all the paper caps ?


Not only does it look nice on it's own, it's also a great match with my 1948 blonde VT-71

Very nice! Lucky for you I didn't see it first. That's the nicest one I've seen.

[bandersen]

Thanks. It turns out I had my variac set to only 105 VAC I brought it up to 117 and the FM started working just fine

[bandersen]

I spoke too soon - the FM band is dead again. I definitely need to do some troubleshooting

[dieseljeep]

Originally Posted by bandersen

I spoke too soon - the FM band is dead again. I definitely need to do some troubleshooting

I just looked at the schematic in Riders 18. It's interesting that the FM IF frequency is 4.3 MHZ, like the pre-war FM sets. The coverage on your set is 88-108 MHZ. The schematic shows a 12AT7 as a 1st and 2nd converter.
Your pictures show where some of the caps were changed, but not all, including the 'lytics.

[bandersen]

I got the radio from this ebay seller: http://www.ebay.com/sch/Radio-Phonog...&_ssn=akachuck

This comes to us from the estate of a lifelong collector in the San Francisco Bay area. Watch our listings for thousands of interesting items as we continue going through this place which has been stacked to the ceiling for years!

So perhaps that previous owner did the partial recap For sure I'll replace the rest when I get a chance.