04-12-2013, 02:58 PM
Before any of the below is considered, you may want to clean all the tube pins and sockets by using DeOxit or similar and rocking the tubes a bit in the sockets. FM is very picky about signal path.
My first suspect would be the 19T8. These have in my experience a very high H-K leakage failure rate. If you have a scope and an isolation transformer, I would trace the signal beginning at the input to the 1st IF and go downstream from there until you lose it. If it's not there at the 1st IF, then you may need to replace the 12AT7.
My first suspect would be the 19T8. These have in my experience a very high H-K leakage failure rate. If you have a scope and an isolation transformer, I would trace the signal beginning at the input to the 1st IF and go downstream from there until you lose it. If it's not there at the 1st IF, then you may need to replace the 12AT7.
