A test that would be interesting to see is if the behavior of how the CW
signals tune behaves the same way when the mode switch is set to SB-N and then
SB-R. They should behave differently from each other, one should tune like you
expect CW to tune. And the other the way you now see CW tune.
If SB-N and SB-R behave as expected then there's a very good chance that one of
the connections between the Mode switch and DSB board is not making the needed
connection when in CW mode. In any case it would be well worth the time and
effort to check the interconnection wire connections between the Mode switch
and the DSB board.
After looking at the block diagrams and schematics it looks like that CW should
tune as if the radio is in CW-N, if the mode is set to CW-R it should tune the
opposite way, and the way you are describing.
So the suggestion that the problem is in the Double Sideband Board (DSB), or
the wiring to it, I think is correct. But it should be noted that in the
Corsair II there is just one crystal that is placed above and below the IF
filter passband by capacitor that is switched into the BFO oscillator circuit
by the positions on the Mode switch. And in the case of the CW tuning the wrong
direction is because that crystal is not running at the right frequency.
So the issue is not related to the PTO or the LO oscillator mixer boards.
Duane
N9DG
> On Aug 25, 2018, at 12:17 PM, Paul DeWitte <k9ot@yousq.net> wrote:
>
> I am not sure how to explain my problem.
>
> I have 3 corsair IIs. recently I got one out to give it some air time. It
> had been a while since it had been used.
>
> When tuning in a signal on 40M I found that instead of turning the VFO
> CLOCKWISE to zero beat on a low pitch signal, I have to go down (counter
> clockwise) to get on frequencey. The offset tuning works the same way. I
> have to tune down to bring the signal up in pitch.
> That is exactly backwards of how TT radios work on 1.8 to 10 MHZ.
>
> Everything else seems to be correct. The frequency readout seems to be
> correct as you tune up the band.It has good rcv audio, and this is the only
> thing that I find wrong.
>
> Is there a wiring problem here? In looking at one of the others, I do not
> see any difference in wire routing.
> Can it be the PTO?
>
> Thanks for any replies,
> 73 Paul K9OT
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