[Hallicrafters] HT-32 sideband oscillator

[Mark K3MSB]

Jeff

I have an old sub chassis;  do you still need those parts?

Mark K3MSB

Sent from my Android phone
On May 26, 2014 6:07 PM, "Jeff" <jeff at podengo.com> wrote:

> Well, an update:
>
> Tore down the side band sub chassis and discovered that the trimmer AND
> crystal appear to be bad.  Was able to get the 13.95 crystal to oscillate
> just wired in without the trimmer, but now THAT's not even working.
>
> So -- I've got a pretty good looking HT-32 that is a door stop right now.
> :'(
>
> So -- anyone got a parts sub chassis?  I'd be looking for the trimmer AND
> 13.95 crystal if you have one, or if the price is right, the whole sub
> chassis.  I hate to relegate this one to a parts rig, since it's in great
> cosmetic shape and had a new rewound power transformer!
>
> Thanks to all who offered advice!  Very bummed now...
>
>
> Jeff
> WB3JIH
>
>
> On 5/20/2014 10:50 AM, Glen Zook wrote:
>
>> Try using the crystal from the HT-32A in the HT-32 Mark I.  If the signal
>> is there with the replacement crystal, then there is a very good chance
>> that the crystal is the problem.  If the problem remains, then look
>> elsewhere.
>>
>> Glen, K9STH
>>
>>
>> On Tuesday, May 20, 2014 7:55 AM, Jeff <jeff at podengo.com> wrote:
>>
>>
>> All:
>>
>> Looking for any advice. I've got an HT-32 Mk I that is dead on 40,15, and
>> 10.  Works great on 80 and 20. I've traced the problem (I think) back to
>> the sideband switching oscillator - the 12AT7 on the sub chassis.  I've got
>> a carrier at 4.050 MHz, but none at 13.95 MHz. Rotating the band switch and
>> function switches produce apparently correct behavior, turning the 4.050
>> oscillator on and off, but I can't get the 13.95 one to come on despite
>> thorough cleaning of switches. Heterodyne oscillator seems to be ok- have a
>> carrier at 21.5 MHz.
>>
>> Resistance is way off on the grid of the 13.95 side -  pin 7 is supposed
>> to be 65k, and it is reading 101k.  Grid 2 is supposed to be 32 vdc, but
>> mine is reading minus 30 vdc.  That's the value on the schematic of the
>> HT-32A, so wondering if that's a typo.
>>
>> I'm having a hard time accepting that a crystal somehow has gone bad, so
>> before I go to the expense and hassle of replacing it, I thought I'd
>> solicit some other opinions. Replaced the 12AT7 with three other tubes -
>> same results.  I've got an HT-32A sitting right next to it, which behaves
>> as expected - so it doesn't seem to be my testing protocols.
>>
>>
>> So, instead of shotgunning components in the sub chassis, anyone have
>> thoughts on a more surgical approach?
>>
>>
>> Jeff
>> WB3JIH
>>
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