11-07-2020, 05:32 PM
Hi.
Well a set back yesterday. I was tidying up the board and silly me didn't remove the PP3. So you've guessed it...... 9V across the filaments. It blew the audio valve but appeared to have not blown the filaments of the RF amp. So I replaced the AF output, oddly the performance is dreadful, as weak as water with odd effects in the audio stage.
Firstly it works better without the 1N60P, as a leaky grid detector but still very quiet, the reaction doesn't now behave as it did either. Also there is more AF gain with the filament on the AF amp running at 0.7v.
Im now thinking that the RF amp filament has been damaged effecting the focus of the electrons onto the anode which could be giving me low output from that stage coupled with a possible faulty new AF amp valve?
Well a set back yesterday. I was tidying up the board and silly me didn't remove the PP3. So you've guessed it...... 9V across the filaments. It blew the audio valve but appeared to have not blown the filaments of the RF amp. So I replaced the AF output, oddly the performance is dreadful, as weak as water with odd effects in the audio stage.
Firstly it works better without the 1N60P, as a leaky grid detector but still very quiet, the reaction doesn't now behave as it did either. Also there is more AF gain with the filament on the AF amp running at 0.7v.
Im now thinking that the RF amp filament has been damaged effecting the focus of the electrons onto the anode which could be giving me low output from that stage coupled with a possible faulty new AF amp valve?
