Recently purchased an SX-122 in great condition.? ?Less cosmetic wear than you'd expect from an early '60s radio.? No mods or changes underneath and very clean there as well.? A few tubes had been changed but several still had the Hallicrafters markings.? Five of the tubes tested below acceptable level on my calibrated Hickok 539, so replaced them with NOS tubes that tested to spec.? The set performed well on my very short length wire that starts on the workbench in the basement and makes it's way up to the roof on the deck.

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With that done, I replaced the two discrete electrolytics, which showed increases in both capacitance and leakage. and ordered a replacement can cap.? Although the set is playing without any power supply hum, I change all 50+ year old electrolytics on general principles.? I located the five paper caps and found them to be high quality, not waxies, and looking as if they just came out of the box.? All five tested on my LCR meter to their nominal capacitance and the leakage was very small and virtually the same as the ones I would have replaced them with.? So, left them in.

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While waiting for the can cap, I decided to give it a preliminary alignment to see how far out it might be.? Tuning up the 50Khz made a big difference.? Had an issue getting an output on the 1,650Hhz IF.? Triple checked my setup, non-inductive 4 ohm dummy load on the audio output with the VTVM measuring across that, and still not seeing what I expected on the VTVM.? Even weirder with the speaker connected.? But, as I said, the set is working the second IF must be too.? Put that on the back burner waiting on some expert guidance and went ahead to the RF alignment.

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Starting with 30 & 14Mhz.? Pretty straightforward and was doing fine.? Got significant improvements at 30Mhz and was feeling good until I got to 14Mhz.? L12, L8, and L4.? Well L12 was no problem as it's threaded section comes an inch or two out of the top of the coil and uses a straight blade screwdriver adjustment (I use on ceramic screwdrivers wherever possible).? Man, that thing twitchy but finally conquered it and got significant improvement.? However things ground to a screeching halt with I hit L8, and L4.? The slugs are recessed and the opening on top has a lot of wax on it.? Doesn't block the hole, but it's darn hard to see down in there and figure out what shape tool is required.? I'm being very cautious about not damaging a slug.? One that I can see reasonably well apprears to have a wide, shallow, common screwdriver slot.? Wasn't able to get anything in that felt like it seated and no changes in output.

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So, to wrap up, I'd appreciate any thoughts on the 1,650 Khz alignment.? And also some guidance on what's needed to turn the slugs on all the recessed slugs.

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Thanks,

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John - K8NN?

Thanks, Jim. ?I could have been clearer. ?The wax is not blocking access to the slugs so won’t need to melt it. ?I can see the top of the slugs but difficult to get enough light in there while seeing past it and determining what style alignment tool is required. ?Being extra cautious in case they’re brittle. ?

Thanks, Jim. ?Yes, it’s a bear to turn over. ?I don’t have full mobility in my left arm which makes it even more exciting. ?Yes, I’m receiving stations on all ham bands thanks in large part to excellent solar conditions.

Peaking the 50Khz in accordance with the manual. ?V3, a 6C4 removed to isolate the IF stages from the RF amp. ?Then signal form a TinySA ?input at Test Point B, measured with DMM at the designated point and the 50Khz If transformers peaked. ?Worked like a cham and no issues.

The test setup for the manual calls for the audio gain to be set at maximum for all the IF and RF adjustments so the technique of using ears and the speaker won’t work. ?Not that you can’t hear it but it’s at rock concert level. ?The book calls for a 3.2 ohn resistor across the speaker and the use a VTVM across the resistor to make the adjustments. ?No problem with that. ?I have a 4 ohm dummy load that I used when working on guitar amp that did the job quite well.

I’m scratching my head over the 1650Khz IF but will try it again after thinking about it for a while. ?It can’t be far off, if at all, because the set is working so well. ?
So I’m going to finish the RF alignment, skipping the slugs for the moment, hook up the antenna and see how much better it hears. ?Expect quite a difference since I’ve already seen big increases in output from 50Khz alignment and the partial RF tweaking even temporarily ignoring the slugs. ?

Obviously I’ll have to do at least the RF section again when I find the key to the slugs.

Hope that answered your questions and thanks again for your input.?

John - K8NN

OK, thanks all.? Finally was able to determine that the slugs have a shallow, wide, screwdriver slot in the top and was able to make the necessary adjustments with my ceramic screwdriver.

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On thing that I should have done but didn't realize until I had it all both covers on and back right side up for listening was to check the 1700Khz crystal and circuit to make sure it was operating and putting the 1700Khz signal to the grid of the oscillator mixer and thus into the second mixer to work with the 1650Khz signal to produce the 50Khz signal to the second IF chain.? So since the dial calibration is off on all bands by a consistent amount, I need to backtrack from the second IF forward to make sure the second mixer is supply an accurate 50Khz output.? My first dual conversion set alignment so I'm learning as I go, following the book's instructions for a change.? All my many earlier and current Hallicrafters restorations have been quite a few of the S-19 thru the S-53A.? I'm finding that dealing with more than one IF frequency is another learing experience.

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I always knew I'd have to redo the alignment after I get the main filter cap replaced so will let that slide until then.? That will save me wrestling it around to get the covers off and get it upside down, right side up, upside down again, and finally right side up for the final time.? Since I'm dealing with a partially impaired left arm, the fewer repositioning actions the better.??

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Thanks all for the help and will report again if the saga warrants.