Jerry, on the 1220, add C86 the "optional" capacitor. However, what
really fixed it for me was adding a .01 uf cap in parallel with C36 near
the PLL circuit. Put the cap on the foil side of the board. Somehow the
tone gets into the VCO directly and after much grounding and shielding,
I found this fix.
It may lower the tone level too much for reliable keying of PL
repeaters. If so you may have to play with the added cap value or change
the coupling resistor between the PL oscillator and the modulator.
73,
Bob WB2VUF
Jerry Schantz wrote:
>
> Morning all,
> Found a pretty nice 555 but need a mobile mounting bracket. Anyone have an
> extra ?
>
> On a different note, have been struggling with the tone problem on the 1220
> with amp. Have made extra shields, decoupled damn near everything with
> caps,rewound coils, changed resistor values, added grounds to the little
> beast but STILL have the issue. Display and led's get brighter on tx, so
> almost positive it's an rf thing. My other one does not do this ! Side by
> side comparison reveals no noticeable differences. Any fresh ideas ?
>
> Tnx
> Jerry W9JJS
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