HW 100 TX woe

[Ed Richards]

Ken;

Sounds like you are right. Something is oscillating or the carrier null
is not working. Use an RF probe and see if you have RF on the
grids/plates of the transmitter string. The block diagram will show you
the path. Where you pick up RF is where the trouble is. Start with the
balanced modulator and work toward the antenna. Be certain to neutralize
by removing plate and screen voltages from the finals and put your RF
probe in the antenna jack and tune the neutralizing cap for minimum. Good
luck.

Ed Richards

On Sat, 24 Feb 2001 21:40:30 -0600 Ken Ketner
<ketner at ARISBEASSOCIATES.COM> writes:
> Greetings Dwellers on the Heath:
>         I am working on a HW 100. I have been having some luck with
> it. Not too
> much worked at first. I went thru the tubes and got a good set of em
> in
> it. That helped a bit. Receiver started to pass some signals weakly.
> Still no RF output, however. Then I discovered it needed 300 volts
> on
> the B+ line, so I rigged up a hi/lo switch for my early but very
> workable HP 23 PS. It now delivers 300 V and that helped some. A
> little
> teeny bit of RF output now and receiver got some stations fairly
> well if
> it was turned up full blast. So I did a complete receiver alignment.
> Turned out the het oscillator coils on every band, and the driver
> and
> plate coils ditto, were way off. After all that adjusting and
> fixing,
> the receiver seems right. So I turned to the TX. I do pretty well on
> receivers, but not so well with transmitters. Anyhow, now it puts
> out
> 100 watts plus. But, the bias is way high. And basically the set
> puts
> out full power if one presses the push-to-talk button. I am thinking
> this means that the PA tubes (6146s) are oscillating. I tried
> adjusting
> the neutralizing capacitor but that doesn’t seem to change the
> condition
> of full-on PA tubes. About my only guess is that something is wrong
> with
> the neutralizing circuit.
>         Any of you greenish chaps got some idears to lead me out the
> dark? I
> think the ole HW 100 ain’t too far from fixed,  but I’m stumped now.
> --
>
> Ken Ketner
> ARS KA5ELD
>                 Personal Webpage: http://www.wyttynys.net
>                 Office Webpage: http://www.pragmaticism.net
> Email:
>         home:   ketner at arisbeassociates.com
>         office: b9oky at ttacs.ttu.edu
>
> US MAIL
> PO Box 65135
> Lubbock, TX 79464
>
> Listserver Subscription:listserv at listserv.tempe.gov - "subscribe
> heath 'name' 'call'"
> Listserver Submissions: heath at listserv.tempe.gov
> Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff
> heath"

Listserver Subscription:listserv at listserv.tempe.gov - "subscribe heath 'name' 'call'"
Listserver Submissions: heath at listserv.tempe.gov
Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff heath"