[Elecraft] 2T Gen problem

[Raymond METZGER]

Hi, 

 

I am in the final alignment and tests of my K2/SSB/PA100, which seems to be
going very well, . but I am facing my first real problem with an Elecraft
kit, the 2 T GEN. 

This is rather frustrating, since there are only a few components, no
toroid, etc.

 

The 700 Hz generator works and produces a max 150 mVolt peak signal, but the
1.900 Hz generator does not work. I noticed that Base of 2N3904-Q1 (1.900
Hz) shows 0 V, while Base of 2N3904-Q3 (700 Hz) shows 2,1 mV. With a 8.9
Volts Vcc, Collector Q1 shows 8,1 Volts while Collector Q3 shows 6.7 Volts.
Drains Q2 and Q4 (2N7000) show both 4.4 V (= Vcc/2). The voltages of pins
1,2,3,5,6,7 of U1 (LMC6482) are all 4.4 Volts. Replacing Q1 with an
available spare didn't help and didn't change the voltages.

 

With the scope, I get a 689 Hz sinusoidal signal on U1 pin 7 (570 mV peak),
but nothing on U1 - pin 1.

There is a "saw teeth" signal on collector Q3, nothing on collector Q1.

 

I have of course inspected carefully the soldering and the component
placement.

 

Thanks for your suggestions,

 

Raymond METZGER

F4FNT