03-06-2011, 07:51 PM
A correction: If you were standing on a concrete floor, with no shoes on, you could get a shock from the radio's chassis if it was plugged in, either on or off.
That doesn't make sense. The B+ produced by the set's power supply is somewhere around 90 VDC. It isn't possible to have 170 VDC anywhere in that chassis, if it's wired correctly.
How are you measuring? DC across the speaker field coil? DC across the audio output transformer? DC from one of these leads to chassis? Any measurements made between a B+ point and ground will not be accurate, since the chassis is isolated from B-.
Also...the radio has only one speaker, not multiple speakers.
Another thing...I don't understand how you can measure infinite resistance across the audio transformer secondary, yet the set buzzes. If the audio output secondary was open, you would not hear anything from the speaker.
I'm not perfect - nobody is - but I have been tinkering around with old radios for 37 years now, and I like to think that I have learned a few things along the way
Quote:Also, the 170vdc was directly from the wires that would go into the speakers. The schematic says it's the BC (broadcast coil, I think), directly from the speaker transformer. The speakers picked up the loud buzz too.
That doesn't make sense. The B+ produced by the set's power supply is somewhere around 90 VDC. It isn't possible to have 170 VDC anywhere in that chassis, if it's wired correctly.
How are you measuring? DC across the speaker field coil? DC across the audio output transformer? DC from one of these leads to chassis? Any measurements made between a B+ point and ground will not be accurate, since the chassis is isolated from B-.
Also...the radio has only one speaker, not multiple speakers.
Another thing...I don't understand how you can measure infinite resistance across the audio transformer secondary, yet the set buzzes. If the audio output secondary was open, you would not hear anything from the speaker.
I'm not perfect - nobody is - but I have been tinkering around with old radios for 37 years now, and I like to think that I have learned a few things along the way
--
Ron Ramirez
Ferdinand IN