[Kenwood] TR-9000 PLL PCB ?

[Steve Harrisonusa]

> Anyone ever had a problem with the TR-9000 or TR9130 PLL board where the
> 14.20055 MHz circuit locks onto the 10th harmonic instead of the 9th as
> it should?
>
> Been playing with this one for a few months as a thought puzzle but
> don't want to replace every component trying to figure out which one is
> offending.
>
> It is the board as a good PLL board brings the radio to life.
>
> The 14.2 Mhz signal is injected through a cap into a resistor and a
> diode. The resistor to ground and the diode to double  tuned  varable L
> fixed C tuned slug transformer .
> Evidently , the non linearity of the diode is supposed to spring up all
> the harmonics of the signal and double tuned network is supposed to
> resonate the 9th harmonic giving 127.805 Mhz signal used in the loop.
> For some reason , this one is resonating to the 10th harmonic and so all
> signals end up off by 14.2 Mhz.

Are you going by what the display says, or are you actually measuring
stuff with a spectrum analyzer (I imagine the latter since a good PLL
board works)? My 9130 has long had intermittent incorrect frequency
display problems (bad vias, I think, but haven't been able to find the one
that's intermittent) but AFAIR, has always been on frequency. Been 6+
years since I've used it, though.

Steve, K0XP