[Heathkit] DX-60 Problem]

[Chris Codella, W2PA]

Harry,

I believe the way this thing works is that V4A a self-biases itself at 
-1V, and pins 6 and 2 should be at around 25V, determined by V4B's grid 
current.   If R26 or R27 were bad that might explain things.  Since 
you're seeing the weird voltage on pin 9 in stand-by (I presume), I'd 
suspect R26.

73, Chris, W2PA

Harry Vaught wrote:

> Everything works except AM.  In AM, it puts out about 50 watts 
> carrier.  I can get some audio from a monitor receiver, but it's very 
> weak and the power meter on my tuner shows almost no modulation 
> swings. Obviously with the voltages so much off, the modulator isn't 
> working well.
>
> There seems to be a general problem with bias, but the bias voltage is 
> good at the source.  I don't know if the problem is one directly with 
> bias, or if it's being skewed by whatever is causing the strange 
> voltages at the modulator.