[Hammarlund] Seeking Guidance to Repair HQ-170

[AW Parker]

Hi Kim,
	Here are some thoughts which might be of help to you.
	The skem I'm looking at shows R-9 as 1k 1/2w (not 1/4).  It's fed from 
the ~255v line to the plate of V2, 6BE6.  If the one in yours was a 1/4 
watt, then it could just that which made it fail.  Use a 1/2w as 
replacement.  C-11 is a bypass to gnd, a .01mf ceramic disc.  Ceramic 
discs rarely get leaky, but it does happen.  If so here, it could be 
drawing extra current thru R-9.  With a replacement R-9 in there, you 
could measure the voltage drop across it and determine the wattage it 
dissipating.
73,
Al, W8UT

On 3/19/2026 10:25 AM, Kim Elmore via Hammarlund wrote:
> I'm still flummoxed.
> 
> The incinerated resistor value is 1 k and it is R9: it was incinerated 
> after serving well (as far as I know) since 1959 when my dad bought the 
> receiver, new. The original manual, in which he notated repairs and any 
> mods, is lost. I have determined that Revision 2 of the manual and 
> schematic apply to this receiver and I have these. Based on the 
> schematic whatever caused R9 to burn up resides somewhere between T1 and 
> T2. I need to check C134, a 2 pF coupling capacitor between T1 and T2 
> but I simply cannot physically find it. While it's a long shot, I need 
> to eliminate it as a cause (make sure it's not shorted) and I can't find 
> it. I know what it should look like, but...
> 
> I've noticed in some images I see of the chassis underside (restoration 
> pages, museum pages, etc.) R9 is clearly NOT original. This leads me to 
> conclude that I'm not the first to experience this failure, but no one 
> so far has apparently run across this, either. R9 is called out as 1/4 W 
> and is on it's own single-lug terminal strip tat is riveted between and 
> just to the right of T1 and T2 so as to avoid the array of trimmers that 
> are the left of T1 and T2.
> 
> Any specific insights and experience with this particular failure are 
> greatly appreciated!
> 
> 73,
> 
> Kim N5OP
> 
> On 3/11/2026 8:12 PM, Kim Elmore via Hammarlund wrote:
>> This is my first post to the group: I have an HQ-170 that has me 
>> flummoxed. It's has been "in the family" since my dad (W5JHJ SK 2007) 
>> purchased it new in May 1959. It, along with his WRL Globe Champion 
>> 350, comprised the first station I operated as a Novice in Fall 1970.
>>
>> While I have a fair bit of experience working on the Champ, I have 
>> very little with the HQ-170: it simply has never needed much. My dad 
>> made no significant modifications to it aside from adding a modern 3- 
>> wire cord, an I.F. out port, and a plug for the mute circuit. A while 
>> back I turned on everything to let it warm up and was alarmed by a 
>> burning-paper smell. The source of the burning-paper odor was the 
>> '170. Upon removing it from the case, I discover half of an 
>> incinerated 1/4 W carbon resistor sitting in the bottom. A brief 
>> inspection reveals the other half remains soldered to a pin on T2, the 
>> transformer just to the rear of the 6BE6 1st converter (V3). The other 
>> side of the incinerated resistor is, or rather was, wired to terminal 
>> strip that has a lead to a pin on T6 (immediately behind V5, the 
>> second converter) that oddly appears to be vacant on the schematic. 
>> The linked image shows where the incinerated resistor was, circled in 
>> red. The resistor you see in the image is a out of my junk box and I 
>> put it there only so I don't lose track of where the incinerated 
>> resistor was.
>>
>> A link to the image is here: https://drive.google.com/file/ 
>> d/1wD4ZJ8Y8QhLlgcJzYyYHEObE5YwCNjAo/view?usp=drive_link
>>
>> I'm posting this in hopes that someone else has encountered the same 
>> problem and can guide me to a proper repair.
>>
>> 73, N5OP
>>


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