[HeathKit] HW-101 Problem

[mike bryce]

ed..

A HW-101 I was working on did the same exact thing. The trouble in this unit
was traced down to the audio stage. the Mic preamplifier was oscillating.
the rest of the radio thought it was a whistle and just went crazy.

it turned out to be a three fold problem. Here's the fix I used.

The four mixer diodes on the modulator board were replaced. Two of them were
open.

The transformer on the same board had an open winding

Tighten up all the hardware holding all the pc boards down.

replace the mic amplifier tube (can't recall its number)

that's what fixed this one up

When the rig is in the tune position....

If you have a scope, there is a cap going to the crystal filter. Sample the
output from the modulator via this cap.   There should be only nice clean
RF. (turn up the mic gain if you have to) If you see audio riding on top of
the RF, then the problem is on this board



--
Mike Bryce
SunLight Energy Systems
"Electricity at the speed of light"

Sponsored by the City of Tempe 

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