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Author Topic: Hammarlund HQ-150 question  (Read 3812 times)
W7GIF
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Posts: 122




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« on: April 17, 2013, 11:49:08 AM »

Recently acquired a truly cosmetically mint condition (inside and out) HQ-150, but got damaged during shipping (broken noise limiter toggle and ganged ac switch/audio gain pot). The shipping container took a substantial impact taking out both of those controls  Cry.

While checking out the damaged controls and checking the receiver for electrical function, I discovered that the power transformer (HV circuit) is like nothing I have seen or have documented in any of my Hammarlund schematics. The transformer is a TRIAD R-16B, and there is a 650 ohm 10W dropping resistor from the CT to ground. Receiver was received with a 5U4-GB rectifier, and all unregulated B+ voltages were approx 30vdc below Hammarlund specs. The dropping resistor installation sure looks "factory", or was done by a VERY meticulous/disciplined party. Having seen similar use of dropping resistors to accommodate use of solid state rectifiers (replacing 5U4's and 5R4's), I installed a 1N1239 in the 5U4 socket to briefly check the resultant unregulated B+. Sure enough, the resultant B+ was spec (310vdc).
Didn't spend any time with the 1N1239 installed, since the 5U4 socket was still wired to the 5vac filament transformer winding, and didn't want to stress the transformer.

Now, the question:
Has anyone EVER seen a factory-original HQ-150 fitted with a solid state rectifier?? Has anyone EVER seen a factory-original HQ-150 fitted with a TRIAD R-16B power transformer??
The subject HQ-150 is a late production unit (S/N B61XX) with the 12AX7 BFO/1st Audio.

Subsequent testing with the 5U4GB installed, revealed that to provide an unregulated B+ of 310vdc, the dropping resistor value needs to be dropped to 430 ohms (was 650 ohms).

Oh yeah, while my schematics show a 4-section filter cap (10-20-20-10), this receiver has a Sprague 3-section filter cap (10-40-40) for the HV, and a separate Sprague 10mfd 100v tubular electrolytic for the 6V6 cathode (which had a "bulged" end-cap, and has been replaced now).

All of the components (dropping resistor, and transformer) SURE look to be "factory-original", as both the added (undocumented) resistor and capacitor are mounted/terminated on stud-mounted terminal posts like those used elswhere in the receiver.

My latest Hammarlund documentation is a manual covering receivers beginning with S/N B5705......but, does NOT document the resistor, transformer, or capacitors in this receiver. The manual has no date or revision ID, just the S/N effectivity.

Any help in sorting out what I have here would be appreciated. Right now, I'm inclined to replace the resistor with a 430 ohm, and keep the 5U4 installed. I'm not a big advocate of the solid state replacements, but without the 430 ohm dropping resistor at the CT, the unregulated B+ is WAY too high (estimated 60 v too high) with the 5U4. I'm not too thrilled with a 5-8 watt heater (dropping resistor) mounted directly below th power transformer. But, short of replacing the power transformer, I don't see many options (other than mounting the resistor outboard on the rear of the chassis, using feed-thru's).

Also on the "hunt" for "original" (American-made) replacements fot the toggle and ganged ac switch/audio gain pot). None of my junk-box toggles have the bat-handle like the original. That figures!
« Last Edit: April 17, 2013, 12:05:35 PM by W7GIF » Logged
KA5N
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Posts: 4380




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« Reply #1 on: April 17, 2013, 12:11:35 PM »

Why do you assume the parts are all "factory original"Huh  From your description I would
tend to think that the original transformer failed and was replaced by the triad xfmr.
Who ever installed the replacement must have juggled parts to get the voltages closer to
original values.  Since the electrolytics have been changed to non-original types, this
bolsters the notion that considerable work has been done on this receiver using non original
parts.   Bat handle toggle switches can be found at various wholesale houses or cheap at
swap meets, just a matter of searching.  Power transformers are becoming more rare and
finding an exact replacement is a problem.  However a few volts difference one way or the
other shouldn't present a problem. The multi-switch is a different story.
Good Luck
Allen KA5N
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W7GIF
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Posts: 122




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« Reply #2 on: April 17, 2013, 01:54:13 PM »

Why do you assume the parts are all "factory original"Huh  From your description I would
tend to think that the original transformer failed and was replaced by the triad xfmr.
Who ever installed the replacement must have juggled parts to get the voltages closer to
original values.  Since the electrolytics have been changed to non-original types, this
bolsters the notion that considerable work has been done on this receiver using non original
parts.   Bat handle toggle switches can be found at various wholesale houses or cheap at
swap meets, just a matter of searching.  Power transformers are becoming more rare and
finding an exact replacement is a problem.  However a few volts difference one way or the
other shouldn't present a problem. The multi-switch is a different story.
Good Luck
Allen KA5N
Hi Allen,
Yes, it's just a supposition that the parts are original. But.....based on the fact that:
The termination posts used are EXACTLY like those used elsewhere in the receiver and uniquely Hammarlund (and appear to be "virgin", and not salvaged from prior installation), and
Lead wirewraps look like the other factory lead wirewraps, and color and workmanship of the solder the same as all other lead connections, and
The resistor is the same manufacturer, vintage, and series as the two other power resistors installed and documented in the parts list, and
The transformer fits exactly the factory original chassis mounting features, including the square transformer case cutout and the frame mounting bolt pattern...
All contribute to my supposition of "factory" installed, given the solder color (alloy and ageing oxidation), vintage and uniqueness of parts (termination posts/standoffs, and resistor), and the workmanship.

Given all of those factors, if reworked, it would have to have been accomplished very early in the life of this receiver, and by a very accomplished, meticulous, and disciplined craftsman who's deserving of praise.

I believe that when the person I bought this receiver from, got the receiver, he replaced the undocumented solid-state recifier with a 5U4GB to make it conform to the documented tube lineup, without realizing the consequences. He has been strangely quiet, and several attempts to get any (historical) information from him on the receiver have gone unanswered.

Ham swapmeets in this neck of the woods no longer have the guys with parts, as they once did.  I'll keep my eye out for a "junker" HQ that I can cannibalize for the toggle switch and ac switch/audio gain control. This radio is too nice to do anything less. Even the tuning capacitor plates are BRIGHT (untarnished/unoxidized) brass  Smiley
« Last Edit: April 17, 2013, 01:57:14 PM by W7GIF » Logged
KE3WD
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Posts: 5694




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« Reply #3 on: April 17, 2013, 04:24:14 PM »

Consider that there are some very fine technicians and technologists among the ham radio community, both then and now.  Capable of performing work that looks exactly like factory. 

Consider that some of these hams may have also worked at the Hammarland plant, or perhaps worked at a repair facility of the period and had access to certain parts. 

Consider time and all that incurs, solder joints can all take on the same look over time measurable in years, plus operating heat, etc. 

Consider that the tube socket is still in the unit, indicating that, if indeed rectifiers were used, they would have had to have been installed in a tube socket base.  Commercial tube socket base replacements that featured solid state rectifiers often had the dropping resistor installed inside, though there were likely some that didn't, or more likely, someone who made their own using an old tube base, soldering the rectifiers to the pins appropriately.  I myself have done that in times past. 

But if Hammarlund would have done the conversion at the factory, I would expect at least labeling at that socket of some sort to indicate the use of solid state rects in the socket, plus the added resistor below in the chassis.  I doubt if the factory engineers would have let it go out the door such that someone could improperly install a 5U4 in there, resulting in degraded performance, a no-no to any engineers involved in manufacture. 

Finally, consider all of the above plus the total life to date of the '150, and it may be that finding out anything more will always have to be chalked up to mystery and wonder. 

You still have one helluva receiver and could simply solder a jumper across the resistor to use the 5U4 in it.


73
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N3DT
Member

Posts: 466




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« Reply #4 on: April 17, 2013, 06:28:35 PM »

I had a 150 that someone stole from me, long story, but it's gone.  I still have the original red "Technical description and Operating Manual" in fairly good shape.  I may part with it for some compensation. It should go to someone with the radio that it belongs to.  I doubt if I'll ever get another.  As I remember, they weren't very good above 15 meters.  Poor image rejection.  But it was my RX for years and worked fine.  I think I even put a hot tube in the front end which did help, but not the images.  The Q-multiplier was outstanding.

Can't help you with your questions though.
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W7GIF
Member

Posts: 122




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« Reply #5 on: April 17, 2013, 07:17:30 PM »

Consider that there are some very fine technicians and technologists among the ham radio community, both then and now.  Capable of performing work that looks exactly like factory. 

Consider that some of these hams may have also worked at the Hammarland plant, or perhaps worked at a repair facility of the period and had access to certain parts. 

Consider time and all that incurs, solder joints can all take on the same look over time measurable in years, plus operating heat, etc. 

Consider that the tube socket is still in the unit, indicating that, if indeed rectifiers were used, they would have had to have been installed in a tube socket base.  Commercial tube socket base replacements that featured solid state rectifiers often had the dropping resistor installed inside, though there were likely some that didn't, or more likely, someone who made their own using an old tube base, soldering the rectifiers to the pins appropriately.  I myself have done that in times past. 

But if Hammarlund would have done the conversion at the factory, I would expect at least labeling at that socket of some sort to indicate the use of solid state rects in the socket, plus the added resistor below in the chassis.  I doubt if the factory engineers would have let it go out the door such that someone could improperly install a 5U4 in there, resulting in degraded performance, a no-no to any engineers involved in manufacture. 

Finally, consider all of the above plus the total life to date of the '150, and it may be that finding out anything more will always have to be chalked up to mystery and wonder. 

You still have one helluva receiver and could simply solder a jumper across the resistor to use the 5U4 in it.


73
Valid points wrt the lack of marking, although without any documentation accompanying the receiver, and a non-communicative seller (former owner), it's not possible to know what may have originally accompanied the receiver.

The 1N1239 that I plugged in to check the B+ with the 650 ohm resistor, provided the spec B+ (no internal dropping resistor). The SEMICON 1N1239 which was commonly believed to be a direct substitute for 5U4's, often found it's way into radios without the necessary circuitry changes required to drop the B+ back down to spec. Such is the case with the 1N1239 that I have. It was pulled from an NC-183D, that had no circuitry mods to accomodate it, and whose B+ ran 40vdc high. Due to the HV winding output of the Triad, the 430 ohm resistor is required with the 5U4 to keep the B+ anywhere near nominal value of the B+. A jumper across the resistor (with the 5U4) results in 310vdc B+ with 95vac primary input (and just 5.3vac on the filaments). That would put the B+ at about 390vdc with 120 vac primary input. Don't think I want to go there.

I've got a 430ohm 10W on the way, and I'll be as happy as a pig in slop when it all goes back together. It is a nice receiver. Unlike National and Hallicrafter, the late Hammarlunds used almost exclusively disc ceramic caps instead of those nasty sure-to-fail tubulars.
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W7GIF
Member

Posts: 122




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« Reply #6 on: April 17, 2013, 07:24:25 PM »

I had a 150 that someone stole from me, long story, but it's gone.  I still have the original red "Technical description and Operating Manual" in fairly good shape.  I may part with it for some compensation. It should go to someone with the radio that it belongs to.  I doubt if I'll ever get another.  As I remember, they weren't very good above 15 meters.  Poor image rejection.  But it was my RX for years and worked fine.  I think I even put a hot tube in the front end which did help, but not the images.  The Q-multiplier was outstanding.

Can't help you with your questions though.
Thanks David. Sure would like that manual. Check your personal messages for my contact info.

73,
Allen
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KE3WD
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Posts: 5694




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« Reply #7 on: April 18, 2013, 06:27:27 AM »

I got ahold of a Heathkit once that came from an SK who had worked in an old RCA plant in the assembly division. 

Under the bottom plate, it was unbelievably nice. 

All the provided Heathkit solid wire was missing and in its place was a MilSpec wiring job complete with hand laced wiring harnesses, stranded wiring with the old cloth over plastic insulation, impeccable "factory" look soldering throughout, just a thing of beauty. 

And - everything worked very well on that transceiver, which was still in alignment. 

Why he did that is likely simple enough to explain, because he COULD. 

Shouldn't have traded that thing off, it would be a real piece to have now, but such is the way of the hobby, at least for me.  Better to let someone else in need enjoy it after a bit, I'm not the hoarding type. 

73
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