[Hallicrafters] HT-32 PTT and runaway in finals

[psturdivant n1ps]

TNX Steven,

Hmmm...going to -120 VDC for the finals bias...are you saying you switched
in the -120 with the radio in standby (to prevent parasitic runaway)?
ps

----- Original Message -----
From: "Steven Grant W4IIV" <stevengrant98 at yahoo.com>
To: "psturdivant n1ps" <sturdivant at adelphia.net>; "Hallicrafters List"
<hallicrafters at mailman.qth.net>
Sent: Sunday, December 22, 2002 3:34 PM
Subject: Re: [Hallicrafters] HT-32 PTT and runaway in finals


>
> The PTT mod sounds fine...i use it and it works fine (i had to disable the
MOX function tho)
> As for the tubes, the way i fixed it was to add a relay to add a high bias
voltage (-120) to the finals this voltage is found before the adjustment
> Also this new relay, if multiple section, can be used for antenna change
over, muting, and amp switching (i do that anyways)
> Also another cool mod is to use an always on transformer for the VFO tube.
That and a christmas bulb (C-6) to heat the vfo (on the bottom) makes it
rock solid
> good luck
>           STEVEN GRANT  W4IIV
>
>  psturdivant n1ps <sturdivant at adelphia.net> wrote:I'm back to the list
after a month or so after changing email.
>
> Hello again.
>
> Anyway, I'm getting ready to get my HT-32 on the air, mostly as an AM set.
> I'm considering adding remote PTT so I don't wear out the Operation
Switch.
> Has anyone tried this? I noted the PTT relay control, V17B, is enabled
> with a contact closure to ground. This could be mimicked via a remote PTT
> switch like a pedal, after reviewing the prints..
>
> Has anyone tried that?
>
> Also, the finals on this set occasionally go into harmonic runaway. I'm
> replacing the finals when some new ones come in. Then I'll neutralize the
> finals....
>
> Has anyone seen a similar situation? This xmitter uses plain 6146 pentodes
> (and I'm staying with the same tube...not the A or B).
>
> TNX
>
> Pete
> n1ps
>
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>
> STEVEN GRANT    W4IIV
>
>
>
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