[Elecraft] [K2] How much AF volts at 1kHz to get full RF power using KSB2?

[Gareth - M5KVK]

I have K2 serial no 03885. I've recently finished building the KSB2 SSB
adapter, but I'm having problems getting it to work.

The problem is very low output power when I speak into the mic. I'm using
an Icom MK36 mic and I've set the P1 header as per the KSB2 manual;
including the resistor to get Mic bias.

The options as set SSBA = 2, SSBC = 2-1 and I've done the carrier balance.

On 7MHz, LSB, with the power set to 1W, when I "tune" the rig into a dummy
load I get 1W, but when I talk or whistle into the Mic, the most I can get
is about 100mW. Nomatter how load I yell, I cannot get full output power
:-) and the bar graph hardly moves.

I've checked all the DC voltages and they are OK. I used a scope on U5
(NE602) and there is an enormous disparity between the voltages on pin 6
(hi) and on pin 1 (very low). The waveform on U3 pin 7 (the compressed AF
out) is greater than that on pin 4, (the AF input), but not by much.

I want to eliminate the Mic as the source of the problem (It works
perfectly with the IC-756 Pro II) by using an AF sig gen, but I'm not sure
how much AF drive should cause 100% output power.

Gareth - M5KVK