04-23-2022, 01:02 PM
Dear Ron B, Terry, Mike, or anybody else who might be able to help,
I just purchased a very nice working signal generator with aim to re-align my 1936 Philco model 60. As instructed by the Philco Service Bulletin No. 164A, I get a nice tone on the speaker by putting in a 460kc rf signal into the control grid of the 6A7 tube and turning the number 17 compensating cap. I can hear getting the tone getting louder or softer as I turn the tread on cap 17 one way or the other. However, other that crude, by ear adjustments, I can't peak by ear alone so I put my old analog Radio Shack Micronta Multitester VOM across the speaker leads hoping to see a voltage change while turning the compensating cap. Even on the lowest setting (0.6 volts DC or 6 volts AC) I can barely see the slightest meter needle movement even when the signal generator gain is turned up and the sound from the speaker is blasting! I know my old VOM is working as designed, is it that the output to the speaker is actually in Milli-volts? I thought the output to the speaker would be in the single digit volt range, am I wrong? Am I doing something wrong or do I need to buy a new VOM meter that can measure in the Milli-volt range?
P.S. - If I do need to buy a VOM that can measure in the Milli-volt range, does anyone have any recommendations as to make and model?
I just purchased a very nice working signal generator with aim to re-align my 1936 Philco model 60. As instructed by the Philco Service Bulletin No. 164A, I get a nice tone on the speaker by putting in a 460kc rf signal into the control grid of the 6A7 tube and turning the number 17 compensating cap. I can hear getting the tone getting louder or softer as I turn the tread on cap 17 one way or the other. However, other that crude, by ear adjustments, I can't peak by ear alone so I put my old analog Radio Shack Micronta Multitester VOM across the speaker leads hoping to see a voltage change while turning the compensating cap. Even on the lowest setting (0.6 volts DC or 6 volts AC) I can barely see the slightest meter needle movement even when the signal generator gain is turned up and the sound from the speaker is blasting! I know my old VOM is working as designed, is it that the output to the speaker is actually in Milli-volts? I thought the output to the speaker would be in the single digit volt range, am I wrong? Am I doing something wrong or do I need to buy a new VOM meter that can measure in the Milli-volt range?
P.S. - If I do need to buy a VOM that can measure in the Milli-volt range, does anyone have any recommendations as to make and model?
