05-09-2022, 09:01 PM
Hi, Cu879,
To clarify, you state that you got Audio at Point C. Do you mean that you injected a signal at Point C and got audio out of the speaker? If that is the case, that proves the 35L6 is good. One does have to put quite a bit into the 35L6, like about 3V to get good volume.
One of the real puzzlers in this mystery is getting 190V on the 6AQ6 (Detector, 1st AF Amp) plate, when the plate is fed through R202 from the 110V B+ supply. (This set employs a half wave voltage doubler power supply; if you fix this it will be aa nice performer.
What is the voltage on the 35L6 screen if there is no signal (volume control set max low)? if it is also 190V, then it is likely that nothing is drawing current and you have a break in the B- circuit. Remember, this is not technically a hot chassis. Chassis is connected to ground through a 0.1 uF Cap (C305) and a 120K resistor (R103). If either shorts, then you will have a hot chassis! However, the 6AQ6 is a class A Amp; it should draw current, even with no signal. If injecting a signal into the grid of the 35L6 produced audio (do this through a 0.01 uF Cap) produces sound, check the following, using the B- side of the 35L6 Cathode Resistor (R204, 150 Ohm) as the B- Reference:
Confirm the plate voltage of the 6AQ6 as being 180V.
Check the Plate voltage of the 12BA6 IF Amp. It should be 110V. If it is also 190V, look for a break in the B- wiring. "Mecca" for B- centers around the 6AQ6, Pins 2, 3 and 6. Check for 0V at the Cathodes of the 12BA6 and the 6AQ6 These cathodes are tied to ground (B-); there is no cathode resistor. Bias is through grid leak. If they are at 190V, check for a cut wire or cold joint. reheat the joints, there seems to be a lot of old 1049 flux on those pins. Don't discount that the cathode of the 6AQ6 is floating.
Hope you get this working. I had the end table version of this set. With an8" Speaker and 190V on the plate, a 35L6 can kick a little @$$
Hope this helps.
Best Regards,
John "MrFixr55"
To clarify, you state that you got Audio at Point C. Do you mean that you injected a signal at Point C and got audio out of the speaker? If that is the case, that proves the 35L6 is good. One does have to put quite a bit into the 35L6, like about 3V to get good volume.
One of the real puzzlers in this mystery is getting 190V on the 6AQ6 (Detector, 1st AF Amp) plate, when the plate is fed through R202 from the 110V B+ supply. (This set employs a half wave voltage doubler power supply; if you fix this it will be aa nice performer.
What is the voltage on the 35L6 screen if there is no signal (volume control set max low)? if it is also 190V, then it is likely that nothing is drawing current and you have a break in the B- circuit. Remember, this is not technically a hot chassis. Chassis is connected to ground through a 0.1 uF Cap (C305) and a 120K resistor (R103). If either shorts, then you will have a hot chassis! However, the 6AQ6 is a class A Amp; it should draw current, even with no signal. If injecting a signal into the grid of the 35L6 produced audio (do this through a 0.01 uF Cap) produces sound, check the following, using the B- side of the 35L6 Cathode Resistor (R204, 150 Ohm) as the B- Reference:
Confirm the plate voltage of the 6AQ6 as being 180V.
Check the Plate voltage of the 12BA6 IF Amp. It should be 110V. If it is also 190V, look for a break in the B- wiring. "Mecca" for B- centers around the 6AQ6, Pins 2, 3 and 6. Check for 0V at the Cathodes of the 12BA6 and the 6AQ6 These cathodes are tied to ground (B-); there is no cathode resistor. Bias is through grid leak. If they are at 190V, check for a cut wire or cold joint. reheat the joints, there seems to be a lot of old 1049 flux on those pins. Don't discount that the cathode of the 6AQ6 is floating.
Hope you get this working. I had the end table version of this set. With an8" Speaker and 190V on the plate, a 35L6 can kick a little @$$
Hope this helps.
Best Regards,
John "MrFixr55"
"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
Best Regards,
MrFixr55
