Voltage issues [solved]

[Flyin_V]

Hi, just fired up the S and found a voltage issue. At 1A and 1B I get 410. At 0A I get 221 but at 0B (and of course 14) I get only 62. If I remove the wire on 0B I get 410. At K reg I get 2.5 (A side) and 0 on the B side. Have 122V AC at the wall.

Is it just a bad Q2 transistor? I attached pics of the board, but everything looks good (I think).

Thanks for any help.

Lary

 

[Paul Joppa]

kreg is the 431 chip witch if correctly wired drops exactly 2.5 volts. Apparently it is shorted to ground, possibly at the tube socket?

 

[Flyin_V]

Great call on the tube socket Paul.

The amp makes music right from initial startup.

I checked the input switch and it only goes to position 1 and 2. Is there a tab that has to be removed to allow it to hit position 3?

Thanks for your help Paul.

Lary

 

[Paul Birkeland]

There's a tabbed washer on the selector switch that sets the stops.  They come set at 3 from the factory, but they can slip out and rotate pretty easily.

If you remove the knob, nut, and lock washer from the selector switch, then slip it out of the chassis, you'll be able to see that tabbed washer.  The tab needs to go in the slot labeled "3" to get 3 stops.  (Note - this can be done with all the wiring attached)

-PB

 

[Flyin_V]

Works perfectly now...thanks PB