The sidetone on my Omni 5 was mushy, especially when using a bug. Dots
were run together and rather erratic. The factor mod to cure this called
for isolating the sidetone's circuit from ground with nylon washers and
cutting the shield on the cable to connector 80. This had already been done
to mine and had no positive effect. After a spending some time with the
scope, here's what I did:
Remove the sidetone's mounting screws and insulating washers (if any).
Turn the sidetone board over and using a single edge razor, cut the foil
as close as possible to the "monitor out" lead. Solder a .01 mfd capacitor
across the cut. Solder a .002 mfd capacitor from the "monitor out" pin to
the ground foil. Reinstall the board leaving out any insulating washers.
What you have done is simply inserted a capacitor in series with the
"monitor out" lead which provides d.c. isolation between the sidetone and
a.f. boards. The .002 capacitor may not be necessary but I felt the extra
bypass was prudent.
73
Steve Ellington N4LQ@IGLOU.COM Louisville, Ky
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