28-11-2023, 08:48 PM
Just to say that this question has also been asked on UKVRRR and the Hacker Radio Group. Mentioning this to avoid the repetition that can result from cross-posted questions.
I think it might be useful to state what test equipment you have access to so we know what tests to suggest. Also, what is your experience with these sorts of things?
But if the EM84 is moving when you tune across the band, that suggests that quite a lot of it is working, and it might just be an issue between the detector and the audio stage.
This might be an obvious question, but have you eliminated the gram socket? When you insert a vintage long-reach phono plug, you break the connection between the detector and the following amplifier. These connections are notorious for tarnishing, and not making the correct contact when the plug has been removed - this could easily be responsible for the symptoms you describe. Connecting an oscilloscope or a bench amp to the tape output would be a good test, or simply getting a phono to phono lead and connecting the tape output to the gram input. Ideally, using long-reach plugs, as mentioned.
If the rectifier has been converted to silicon, there should be a series resistor to limit the HT. What is the HT at the moment?
I think it might be useful to state what test equipment you have access to so we know what tests to suggest. Also, what is your experience with these sorts of things?
But if the EM84 is moving when you tune across the band, that suggests that quite a lot of it is working, and it might just be an issue between the detector and the audio stage.
This might be an obvious question, but have you eliminated the gram socket? When you insert a vintage long-reach phono plug, you break the connection between the detector and the following amplifier. These connections are notorious for tarnishing, and not making the correct contact when the plug has been removed - this could easily be responsible for the symptoms you describe. Connecting an oscilloscope or a bench amp to the tape output would be a good test, or simply getting a phono to phono lead and connecting the tape output to the gram input. Ideally, using long-reach plugs, as mentioned.
If the rectifier has been converted to silicon, there should be a series resistor to limit the HT. What is the HT at the moment?
