[Hammarlund] HQ-170 Query

[manualman at juno.com]

The Hammarlund HQ-170 was in production from 1958 to 1962.
All 4 issues of the schematic show the same value of the resistor, 27K 2
watt.
The only thing major to the HQ-170 later in its life cycle was in the AGC
circuitry which, I believe, they tried twice. They didn't get close until
they introduced the HQ-170A.
Most likely Issue 1 or 2 would be the logical choice for your receiver.
Replacing the resistor isn't enough; you need to find out why it burnt
up.

Serial number generally can be found looking at the rear of the chassis
apron lower left side. If it's still visible, it can be stamped or
embossed. A magnifying glass can help.

Pete, wa2cwa


On Tue, 27 Jan 2026 16:56:38 -0600 Kim Elmore <cw_de_n5op at sbcglobal.net>
writes:
> I have an HQ-170 purchased new by my dad (W5JHJ SK 2007) in 1949. It 
> has 
> developed a problem, characterized by an incinerated resistor on a 
> line 
> coming off of pin 6 of V5 (third mixer). I no longer have the 
> original 
> manual and I cannot find a serial number ion it anywhere. I have 
> seen 
> (but no longer have) the original purchase receipt for it, dated May 
> 
> 1959. I've determined that there are at least four different 
> schematics 
> for the receiver for various production upgrades. I'd like to ensure 
> I'm 
> looking at the right schematic, but without a serial number I'm a 
> bit in 
> the dark. It's in beautiful condition since he, and later I, took 
> great 
> care of it.
> 
> I'm not as familiar with the HQ-170 as I am with his WRL Globe 
> Champion 
> 350, also purchased new by him in June 1959, and slo in superb 
> condition. I've worked on the Champ a fair bit (now needing a LV 
> transformer replacement) but aside for alignment and preventive 
> maintenance/electrolytic capacitor replacements in the HQ-170, this 
> is 
> the first time I've had to get into it. How do I know which 
> schematic is 
> the correct one to use?
> 
> 73,
> 
> Kim Elmore N5OP
> 
> P.S.: The HQ-170 is currently off of the bench so that I can address 
> the 
> Champ's LV transformer replacement.