HW101 Modulation

[nb9m at RNETINC.NET]

Jerry, I'd think the first order of buisness is to check at the microphone
end.  Listening on a nearby receiver on your transmit frequency, unplug your
microphone, key the PTT line (short the PTT pin to ground using a screwdriver)
and put your finger on the mic audio pin of the mic jack on the front panel.
You should hear a hum in your receiver.  An audio generator (cranked way down)
or a signal tracer to inject some audio is good, too.

If you still don't get audio, pop off the bottom cover and check for
breaks/bad solder connections in the shielded cable routed from the front
panel mic jack to a PC Board.

Make sure the applicable tubes are seated well and have clean contacts, and
tap them gently while observing the results.  Poor solder joints and fatigued
connections resulting in breaks can be common in kit construction.

Check the solder joints on the PC boards; sometimes the copper circuit traces
break or crack through time because the brittle fiberglass substrate is
subjected to localized high heat. On the HW-101, intermittants can occur when
the metal shields soldered to the bottom of the PC boards touch something
they're not supposed to (like a copper trace underneath.)

If all is still OK, check the applicable tubes.  If they check OK, THEN it's
time to break out the voltmeter and ohmmeter to locate leaking caps, open
resistors, etc.

Best of luck!
-Brad, NB9M

Quoting "H.G. Jerry Dowell" <RECCOP18 at AOL.COM>:

> Gentlemen:
>
>        My perfect HW101 has a need for the Emergency Room. In perfect
> condition till last weekend, and Now, it will no TX in USB / LSB in the SB
> mode.  I'm getting a solid AM type carrier. Everything else OK.  Need help.
> Advise.
>        Again Soon
>
> W0GYR
> H. G. Jerry Dowell
> 19201 E. Truman Rd.
> Independence, Missouri
> 64056-2432
> 816-796-0800
> RECCOP18 at AOL.COM
>
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