Gareth,
During transmit you should have about 1.4 volts DC on pin 1 or the
balanced modulator U5.
I just measured the U5 pin 1 audio using a 'scope with a 10X probe and
found the peak to peak voltage ranged from 200 to 400 millivolts. If
you have a good microphone, you should see a similar amplitude signal.
The RF output at U5 pin 4 should have a similar amplitude.
The BFO injection at U5 pin 6 should be greater than 200 millivolts peak
to peak and on the one I just measured there was a 1 volt BFO signal there.
73,
Don W3FPR
On 9/29/2014 4:52 AM, Gareth - M5KVK wrote:
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.
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
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