01-18-2018, 01:26 PM
Hi all,
Maybe someone will give me some insight into what's going on with my 90. It's the chassis with one 47 tube. I've re-capped it and replaced most or all resistors. About half way thru re-capping I powered it up and had reception at a low volume. When complete I again had reception at a low volume for a couple of minutes then some crackles, then some more crackles, then dead. First I looked at the last thing I did which was restuff the two tobacco cans, #24 & #30. I didn't take them back apart, but proper capacitance was there on all. I checked and rechecked my wiring and the tubes. The primary in the first detector transformer #7 checked open, so I rewound that. Still dead. One day I went to pull the 47 output tube to listen for the click and at one point of the pin contact all of a sudden the sound came blasting through beautifully loud. Great! I think that I merely have a pin contact problem. Playing with the 47 pin contacts worked for a short while then it went dead again. Now, can't get anything again. At one point about the time it went dead again I accidently shorted across a compensating condenser, possibly #9 across the 1st IF primary. Something that I don't understand is why when I check across the coils of both IF transformers they come up open. They can't all four be open, I'm misunderstanding something. Does it have to do with the compensating condensers?
Thanks for any insight, I have the cabinet looking quite good so I'm looking forward to figuring out my chassis problem.
Alan
Maybe someone will give me some insight into what's going on with my 90. It's the chassis with one 47 tube. I've re-capped it and replaced most or all resistors. About half way thru re-capping I powered it up and had reception at a low volume. When complete I again had reception at a low volume for a couple of minutes then some crackles, then some more crackles, then dead. First I looked at the last thing I did which was restuff the two tobacco cans, #24 & #30. I didn't take them back apart, but proper capacitance was there on all. I checked and rechecked my wiring and the tubes. The primary in the first detector transformer #7 checked open, so I rewound that. Still dead. One day I went to pull the 47 output tube to listen for the click and at one point of the pin contact all of a sudden the sound came blasting through beautifully loud. Great! I think that I merely have a pin contact problem. Playing with the 47 pin contacts worked for a short while then it went dead again. Now, can't get anything again. At one point about the time it went dead again I accidently shorted across a compensating condenser, possibly #9 across the 1st IF primary. Something that I don't understand is why when I check across the coils of both IF transformers they come up open. They can't all four be open, I'm misunderstanding something. Does it have to do with the compensating condensers?
Thanks for any insight, I have the cabinet looking quite good so I'm looking forward to figuring out my chassis problem.
Alan