[Hallicrafters] HT-32 sideband oscillator

[Jeff]

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
>
> ______________________________________________________________
> Hallicrafters mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hallicrafters at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Hallicrafters mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hallicrafters at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html