[Hammarlund] HQ140X questions

[Dan Martin]

My hunch is the mystery connection and chassis jack was someone’s field conversion to make an HQ-150 out of an HQ-140. The underside of the 150 has the blue wire going from pin 5 V-3 to Z1. The 150 also has a thin jacketed coaxial cable connected to pin 5 that leads to the Q-multiplier function of the 150. 

The couple of times I’ve seen this before the interface jack has been on the rear panel where it’s easier to connect and route to an outboard Q-multiplier than with a jack on the top chassis surface.

A segment of the HQ-150 schematic is attached showing the internal wiring of the Q-mult. to pin 5.

Dan
WB4GRA


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Sent from my iPhone

> On Dec 13, 2023, at 4:33 PM, Richard Knoppow <dickburk at ix.netcom.com> wrote:
> 
>    Maybe, but its a peculiar mod. The blue wire will be the normal IF feed from the mixer to the IF, so it appears that either the IF is being fed to something external or its a means to feed an external signal at the IF frequency to the IF. One would think an SSB adapter would be fed from later in the IF chain. Maybe someone else will recognize what it is or figure it out.
> 
>> On 12/13/2023 9:45 AM, Ray G3XLG via Hammarlund wrote:
>> Just had a look Richard, the centre pin of the strange chassis connector
>> goes via a 56K resistor to pin 5 the anode of V3 the mixer.
>> A blue wire also on pin 5 goes up through the chassis to T1 between the
>> mixer and the first 1st IF.
>> I think you are right it's a Ham mod, perhaps to feed a signal generator?
>> 73
>> Ray G3XLG
> 
> 
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> SKCC 19998
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