HW-101 IF receive oscillation problem after long transmission

[Kenneth G. Gordon]

On 22 Jan 2007 at 14:30, charlesmorris at hughes.net wrote:

> But now it has another IF problem, an intermittent oscillation after
> long periods of transmitting, which I discovered this weekend. I
> usually keep my transmissions short but on Saturday morning I had the
> chance to be a bit long-winded. When I let go of the mike button, the
> receiver was completely cut off and the S-meter was nearly pinned. It
> very slowly returned to normal over about 15 seconds. On subsequent
> short transmissions, operation was normal, but on any extended
> key-down it recurred.

<much good stuff snipped>

The FIRST thing I would do if I were in your situation is to check and 
tighten each of the many nuts-and-bolts that hold each of the separate 
circuit boards to the chassis.

I have cured situations similar to yours by doing the above.

You MAY have to remove all the above-mentioned nuts-and-bolts, 
clean the contact surfaces between each circuit-board and chassis, and 
re-install the bolts, but I have never had to do this...yet.

DeOxit-5 is simply wonderful stuff!

There is a Heathkit service bulletin that describes an added ground in 
the vicinity of the IF circuit board which also may address your problem.

As I remember it, there are a BUNCH of white (or possibly brown) wires 
all going to one particular place near the edge of the board in question 
and one must add a wire to tie that bunch of wires to the chassis at that 
point.

But you better check the Heathkit service bulletins to make sure which 
is the correct bunch.

Ken Gordon W7EKB

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