Newbie's First Questions RCA TS 721 Restoration

[Yamamaya42]

That should be a start point then in tracking down the lack of sound, even though the linked Rider's may or may not be exact to what you have, the voltages shown should be close enough to give you a hint of the problem.

be it a bad tube, or resistor or cap or what ever.
the voltages on the 6K6 and 6AT6 should be pretty close to matching what you see in the schematic.

[Chris K]

Originally Posted by Yamamaya42

That should be a start point then in tracking down the lack of sound, even though the linked Rider's may or may not be exact to what you have, the voltages shown should be close enough to give you a hint of the problem.

be it a bad tube, or resistor or cap or what ever.
the voltages on the 6K6 and 6AT6 should be pretty close to matching what you see in the schematic.

So looking at the Riders and the audio output 6K6, I'm looking at 6.3 AC on pins 8, 7 and 2, -14 volts DC on pin 5, 185 volts DC on pin 3 and 200 volts DC on pin 4? Do you concur?

[Yamamaya42]

Originally Posted by Chris K

So looking at the Riders and the audio output 6K6, I'm looking at 6.3 AC on pins 8, 7 and 2, -14 volts DC on pin 5, 185 volts DC on pin 3 and 200 volts DC on pin 4? Do you concur?

pins 8 & 7 are tied to gnd so they are 0v , pin 2 is heater at 6.3v AC, pin 4 (ctrol grid) is tied to bias & the red wire of the output via 1k resistor to +225, should be about 200v, pin 3 is hooked to pin 3, plate and will be lower because of the 500 ohms of the output @ 185v, or so they say.
pin 5 is pulled negative via 470k

[Chris K]

Originally Posted by Yamamaya42

pins 8 & 7 are tied to gnd so they are 0v , pin 2 is heater at 6.3v AC, pin 4 (ctrol grid) is tied to bias & the red wire of the output via 1k resistor to +225, should be about 200v, pin 3 is hooked to pin 3, plate and will be lower because of the 500 ohms of the output @ 185v, or so they say.
pin 5 is pulled negative via 470k

Learning so much here...thank you very much. I'll get to work!

[old_coot88]

Originally Posted by Yamamaya42

pins 8 & 7 are tied to gnd so they are 0v , pin 2 is heater at 6.3v AC, pin 4 (ctrol grid) is tied to bias...

Um.. small nit, but pin 4 is screen grid, pin 5 is control (signal) grid.