[mikethedruid]

Did more on the HQ-129-X today. I wired in the 3 wire antenna connector after studying the connections carefully. I also took pictures of the audio gain control and multi section condenser can I replaced, as well as the antenna connector.

[Image: https://64.media.tumblr.com/55954a30630b...7d0275.jpg]

[Image: https://64.media.tumblr.com/6f5b1392ae81...215f44.jpg]

The ground terminal on the antenna strip is connected to a wire that is soldered directly to the chassis. The two antenna terminals are wired to the terminals on S6 as indicated on the schematic. That pretty much winds up the under chassis work, unless I decide to install the frequency standard. I'll think about that over the next few days. Before I can do that I need to test this beast, and align it.

[mikethedruid]

All the under chassis work is done, all the paper and electrolytic condensers have been replaced, all out of spec resistors have been replaced. The front panel has been put back on, and all the knobs are back on. The initial test, power up without tubes has been done, and the 6.3 volt filament supply works, as shown by the dial lamps. Next test will be with all the tubes except the 5U4 rectifier. I'll do that tomorrow.
[Image: https://64.media.tumblr.com/c3e98bf8626e...ec648b.jpg]

[mikethedruid]

Well, it works ! Today, first I put in all the tubes except the 5U4 and powered it up... the filaments in the 6V6 and the 6SN7 both glowed nicely, and no smoke escaped from anything. Then I connected a speaker to the speaker terminals, and an antenna to the antenna terminal, and jumped the other antenna terminal to the ground terminal. Powered it up again, and BINGO... sound... sound that got louder and fainter with the volume control. I was even able to hear a station weakly on the AM broadcast band on the lowest frequency band, as well as the usual hash from the power lines. I could hear two stations weakly on the next band which has the upper end of the broadcast band, as well as the hash where it is expected. I worked my way up the bands, and they all seemed to be receiving, though faintly. All the controls also seem to be working properly. I was even able to listen to a couple of hams up around 7 MC on single sideband using the BFO, which also seems to be working fine. Next will come alignment.

[mikethedruid]

Before I left off with the Hammarlund this afternoon I sprayed all the sections of the band switch well with de-oxit. This evening I began to check the alignment. The IF proved to be very close, and, not wanting to go through the whole process involved because of the crystal filter, which seems to be working OK, I left it alone. After that I worked on the low end of the broadcast band (.54 to 1.32 MC), and then the next band up, the high end of the broadcast band and low shortwave (1.32 to 3.2 MC). My dogs were outside, and they began to bark at the back door, so I left off to let them in. I'll resume work tomorrow.
[Image: https://64.media.tumblr.com/b64e5bcbb0d0...0ef72f.jpg]

[Joe Rossi]

Great narrative and documentation. Nice radio!

[mikethedruid]

I went back to things tonight working on the 3.2 MC to 5.7 MC band, but I'm having trouble getting everything to line up. When I get the low end tuned at 3.5 MC, using the coils, then the upper end, tuned at 5.5 MC is way off. I've played with it quite a bit, but just can't get things to line up at both ends.

[mikethedruid]

I learned something new today. I tried everything to get the 3.2 MC - 5.7 MC band to line up, but it just wouldn't. Now, I had the bandspread set to 0, as one might assume that would be the point that gave 0 deviation from the main tuning dial. BUT NO ! Finally, in complete frustration, I tried setting it to the other end of the dial at 100, and lo and behold, the band aligned correctly ! Now there is nothing on the bandspread dial that says "set here" or some distinctive mark, as there are on some bandspread dials, nor is there anything that I could find in the instruction manual. In fact, the manual is pretty deficient in information on alignment. It seems to be purposely that way so that owners would have it serviced by Hammarlund rather than tackle it themselves. (Which is odd knowing hams as I do, they LOVE to play with their gear.) Anyway, once I had that band sorted out, I went back and checked the alignment on the .54 to 1.32 MC and the 1.32 to 3.2 MC bands. They were right on, since, according to the instructions, the bandspread does not work on those two bands, only the upper four bands where popular ham bands are found. So, that was my work this evening, and I am pleased with the result.

[mikethedruid]

Last night I spent time aligning the rest of the shortwave bands. It all went pretty smoothly. The top band, 18-31 MC seems to have a problem which I will have to look into. It seems dead, not picking up anything at all. The other bands are working OK. On the AM broadcast band, which is split between the two lowest bands, I pick up stations all across the AM frequencies from 550 to 1600 KC. From what I hear, I would say this receiver is slightly better than my National NC-125 or my Lafayette HE-30.

[David]

Hallicrafters did the same thing, some model sets to 0 others 100.

[mikethedruid]

Worked on the Hammarlund some more this evening. I got the highest band working now. I'm sure the problem is just dirty contacts in the band switch. I have more De-oxit coming, should be here in a couple of days. I'll spray the sections well again when it comes. I noticed that the S meter has stopped working. I am tackling that next. I think it was a short to chassis by one of the wires to the meter. The rubber grommet through the chassis to protect them had completely rotted, and its remains fell apart when I went to pull back the wires. I replaced the grommet, and now am going to replace the wires. Tonight I also tweaked the RF tuning using actual stations at the top and bottom of the various bands, which has further improved reception. It is now VERY good, certainly as good as any of my communications receivers except my other Hammarlunds, my HQ-140-X and HQ-145-X.

[mikethedruid]

Well, the electronics work is done, and the HQ-129 works quite well. I ordered a set of chicken head knobs and a pair of what appeared to be original style tuning knobs when I went back to work on the radio, and, after so long away from it could not remember where I had put the knobs I took off. Of course, as always happens, I found the knobs I had taken off right where I had left them, in a plastic bag in the bottom drawer of my work bench ! I had looked a number of times, but somehow missed them. If they were a dog they would have bit me ! Anyway, the radio looks even better with these knobs. The main tuning and bandspread knobs are very close to the originals, and allow one to see the lettering "MAIN TUNING" and "BAND SPREAD", which the knobs that came with it did not. So, now all I really have to do is strip and re-paint the cabinet. I am seriously considering having it "dipped" like they do with car bodies. It will get off all the old layers of paint and allow me a fresh start. That can all wait until the weather warms up some. So, here's what the radio looks like with the new knobs....
[Image: https://64.media.tumblr.com/26ba0b66e3f5...702f88.jpg]

[mikethedruid]

I've been reading through the manual on the HQ-129-X and have figured out that I have to redo the alignment and reset things to the actual IF frequency determined by the CRYSTAL in the crystal filter which may not be exactly 455 KC. I looked at the method outlined in the manual, which would equipment I do not have, and then figured out my own way of doing it. Here is a schematic so you can follow along...

[Image: https://64.media.tumblr.com/18a5dd7cb768...73ef9d.jpg]
 
The first order of business is to figure out the actual frequency of the crystal in the crystal filter. To do this I first pulled out the 6K8 so it would not be generating any spurious IF frequency to mess things up. Next I fed a modulated signal starting at 455 KC into the circuit at pin 4 of V3, and hooked the probe from my scope to pin 8 of V4. I set the crystal filter to the second notch and tuned my signal generator up and down until I had the highest output on the scope and by ear from the speaker. I then tuned the adjustments on the crystal filter until the signal got its loudest, then turned the crystal filter to its maximum setting, and again tuned everything to the maximum, again starting by re-tweaking the signal generator VERY carefully for maximum output from the scope and speaker, then re-adjusting the crystal filter adjustments.

Once that was done, I checked the output frequency with my Tecsun PL-600. It turns out the crystal is 453 KC. I left the signal generator set exactly as it was, and then re-inserted the 6K8 tube, but did not attach the grid cap, but instead fed the signal from the signal generator through a 220 mmf condenser into the grid cap. I then re-adjusted T1, T3, T4, & T5 to 453 KC. It didn't take much adjustment at all. Tonight I will go over the full alignment of the set, and tweak all RF and oscillator adjustments so that everything aligns right.

With the crystal filter adjusted, and the IF reset to the new frequency, there seems to be much less drop off of signal now when using the crystal filter, which makes sense, since I had set the IF to 455 when I aligned the transformers before, and the crystal filter was just enough off to begin to really squash that when set to its tightest notch.

So, for those of you who ever have to do it and don't have a swept signal generator, there is a method for checking the frequency of your crystal filter and adjusting it, so you can set your IF to the right frequency.

[mikethedruid]

Past two nights I have been carefully realigning the radio, first with my signal generator, double checking the frequency with the PL-600, then doing final tweaking with live known stations to get the best reception. With everything done I would rate this receiver a little above my National NC-125 and my Lafayette HE=30, about on par with my Scott SLRM, and almost as good as my Hammarlund HQ-140-X

[mikethedruid]

The HQ-129-X is done, as good as I can get it. It is receiving well on all bands. The crystal filter works like a champ now, suppressing adjacent noise from the desired station. Even on the AM broadcast band, if one just uses the first notch it greatly improves the reception and signal to background noise. All in all I am quite pleased. Sadly, the signal strength meter does not work. I have tried and tried to get it to work, but to no avail. Finally I measured to see if it is open, and it is... infinite ohms. C'est la vie ! Other than that this is a great old radio receiver.

[mikethedruid]

Today I finally got off my lazy butt and began to strip the cabinet. It has several layers of old paint, the top one being silver. it seems to be applied over some other paint which, on the sides and back crinkled badly. The inside of the cabinet has a black crinkle paint, very fine textured, not like the outside, which may be original. Today I managed to clean off the top and the back. The back, with all the louvers was a pain. I have gone through about 3/4 of a can of paint stripper, and the same of mineral spirits. I am wondering what the original color and texture of the cabinet was; if it was the battleship grey of my HQ-140-X and HQ-145, or something else. If any of you know for sure, please let me know. Thanks.