65 maggie

[DaveWM]

that tube is also one of the difference amps.

[DavGoodlin]

Originally Posted by timmy

i thought if you pull the blanker tube out the screen is supposed to black out. well it dont its all green and bright

The blanker 6GU7 is also the G-Y demod amp, so that makes sense. what happens when you pull the other 6GU7? Bright magenta, right?

[DaveWM]

Originally Posted by timmy

6gu7 pin 7 bias down 1.325v bias up -3.53v no diff bright up or down.

pin 8 voltage? crt bias up crt bias down?

[timmy]

pin 8 bias down 6gu7 7.35v bias up 5.95v

[timmy]

what if i was able to get pin 7 voltage of the 12gn7 down to maybe 185v instead of 255v. the lower this voltage the brighter it should be, maybe. but then again how would i do this anyhow.

[timmy]

the silvertone at full brightness is around 145v at pin 7 of the 12by7 if this is where the problem is in this maggie, video output, then maybe it would work ? i checked all the resistors around the 12gn7 tube and found not a thing.

[DaveWM]

again, you need to try a different tube. a weak video out tube will allow the plate voltage to be excessive

[timmy]

i did

[DaveWM]

Try a new audio output tube.

[timmy]

audio output , lol,???????

[timmy]

i thought about adding more big vintage speakers too but realized that wouldnt work...

[timmy]

a 1 meg ohm 1 watt resistor from pin 7 to ground should drop it some.........

[DaveWM]

this set uses a stacked B+ from the audio out to supply the screen voltage of the video out (as well as other tubes). It also supplies the hot side of the brightness control. You should be able to locate that 3.3 meg now, it has the 135 (or what ever is the output from the stacked B+) on one side the other goes to the brightness control.

[Bill R]

Sams shows pin 7 of the 12gn7 to be 300V. Pin 8 should be 135 volts, which comes also from the cathode of the audio out tube.

[timmy]

so if i have 122 volts at pin 8 would this suggest that the 3.3 meg resistor went up in value ? would this resistor be on the audio board or the chroma ?