Omni V Mushy Sidetone Mod

From the Ten-Tec Reflector October 30, 1996

The sidetone on my Omni 5 was mushy, especially when using a bug. Dots were run together and rather erratic. The factory 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 Louisville, Ky