KSB2 No Transmit Audio

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KSB2 No Transmit Audio

Beth Wenzel
Hi guys, i built my k2 about a year and a half ago, I've recently decided to add a Ksb2, all wen together well, but... alas it doesn't work. I've checked all of the signal voltages, everything is ok. I've traced (with an o-scope) a nice looking modulated signal to the top of D3, then nothing. Checking D3 in circuit it looks ok (.6 ohm forward, > 100k reverse) I'm assuming the sig should pass through to the base of Q3 (?).

Is there a circuit description that can help me with the trace?

73 AB9LZ Mark,
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Re: KSB2 No Transmit Audio

Don Wilhelm-4
Mark,

The path through Q1 is only used in CW mode to make the path from the
BFO to the Transmit Mixer (on the RF Board) complete - that circuitry
replaces C167 which you removed from the RF board.
For SSB, the Balanced modulator signal goes 'backwards' through the
filter and is applied to Q2 where it should find its way back to the RF
board and on to the transmit mixer.  Be certain the TXC signal is
operating correctly - it should be near 6 volts during CW transmit and
near zero during SSB transmit.

If you need more detailed info, please ask.  I do not know of a document
with that level of detail other than the schematic.

73,
Don W3FPR

Beth Wenzel wrote:
> Hi guys, i built my k2 about a year and a half ago, I've recently decided to add a Ksb2, all wen together well, but... alas it doesn't work. I've checked all of the signal voltages, everything is ok. I've traced (with an o-scope) a nice looking modulated signal to the top of D3, then nothing. Checking D3 in circuit it looks ok (.6 ohm forward, > 100k reverse) I'm assuming the sig should pass through to the base of Q3 (?).
>
>  
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