De-Tickling the Hallicrafters S-120

[@davidportch8837]

Thanks Mike for another very entertaining and informative video... much appreciated...

[@MIKROWAVE1]

I have the final video hitting Tomorrow WED.

[@Chris_Grossman]

I have some old equipment I want to restore. I never thought about the issues with rivets. That is a good piece of advice I will check in the future. Thank you for the lesson. I very happy I learned something here!

VE2ZAZ here. My neighbor has just installed a swimming pool heater, likely of the "Inverter" type. It wipes out my HF bands up to 6m. On the spectrum, I can see noise bumps covering the entire spectrum. What a nuisance! Luckily, the bands are going to be quieter in the winter...being in Canada! Thanks for your nice videos.

[@MIKROWAVE1]

Looks like you need to bring him a case of beer and see if you can eyeball the installation. Noise can be reduced if not eliminated with enough beer.

[@acestudioscouk-Ace-G0ACE]

I have noticed that AM seems to suffer high noise levels more. I went to a radio club meeting last night on EMC (electro magnetic compliance) and they were testing items members bought in. One member bought a filter from an old washing machine which he then built into mains extension lead and socket. This tested the cleanest of all items tested that evening and there were no nasty spikes. I will try this for myself because I was so impressed.

[@davidcampbell6527]

Glad to see that radio didn't bite you Mike!

[@MIKROWAVE1]

Ha nope - covers are on and I lived!

[@turtlekoff1]

Another great video.. thanks Mike

[@MIKROWAVE1]

Thanks for watching another old radio video.

[@SpinStar1956]

Personally, I like to use some braid from RG-58 coax attached to the chassis, then run the ‘hot’ lead through it, in situations like this. You can use a single copper wire or even Teflon tubing, to preform the route and tack solder it in several places. Really appreciate you restoring this great radio, to give it every chance of being used and around for the future! 73…

[@Capecodham]

What was the purpose of the word personally?

[@SpinStar1956]

@@Capecodham Personally you see, it’s like an uncontrollable-tick that comes from being traumatized as a young child, by a peremptory-teacher (english to be sure). An officious ‘little’-man of a pedant, frittering about from milieu to milieu, dispensing his unwanted pearls. Being largely unaware, self-adulatory, and imperious, he had a dickens of a time comprehending even a simple social-ambiance, the very-type that fills many pages of a DSM; but more-importantly, to appreciate time itself, and life’s inestimable value. But it still consumed him, these piddling-infractions, day and night, even while inextricably and evermore-approaching, his beautifully-polished but yet unfinished black rock. KN…

[@MIKROWAVE1]

I tried this and it helped some. But the root cause is still leading back to the Couplate multi component blisterpack.

[@SpinStar1956]

@@MIKROWAVE1 Mike, I pulled a print (poor quality) and at least the values are given. If it were mine, I’d just remanufacture the Couplate since even if you did find one (say an old Centalab etc.) it may have components that are bad or shifted. When I worked for a jobber right out of high school, we sold tons of them, stocking several hundred types. The TV guys would come in, and invariably ask for one we didn’t have; they would be so mad pounding on the counter, telling us what a 2-bit operation we were running, then ask me to order it; just for spite, I’d make them prepay or put it on their account! So, my vote is you get out the Vectorboard and build one; you can always dip it in some dark-yellow plucky if that floats your boat! Sounds like a video to me!😉

[@brunoprimas1483]

Nice to have a video show that SSB can be heard on these receivers. I've seen more than one KZbin video saying that these are "AM only".

[@MIKROWAVE1]

More coming in the Alignment Video.

[@sinewave4236]

I’m impressed that you had the BFO working - I’ve never really managed to use it on SSB with this model. Thanks for the detailed work on a radio that is often spoken unkindly of in the forums - I might have to revise my opinion of it !

[@MIKROWAVE1]

After the recap, clean up on grounds, and Deoxit on the variables and BFO pot, it is "passable" on CW and fair on low signal strength SSB. But most radios are not in this refurbed condition. Even so, you we need to adjust the BFO feedback pot clockwise to get the injection right for the signal. Just into oscillation, it is almost like a regen with a big sort of useless gain bump for CW because there just is not enough injection to take advantage of it.

[@W1RMD]

I've got what I think is about a 300 watt or better slobbering iron that works great slobbering the rivets to the chassis. I have a 250 watt slobbering gun which is good too. but doesn't get nearly as hot as the iron. Not sure if they still make those giant irons. I bought a couple at a flea market and it looks like they're from the 1950's or earlier.They work the best if you can find them, and you don't have to warm them up each time and no tips to keep tightening. A metal napkin holder makes a great holder for them. I like using a piece of electrical wire for the tip on the soldering gun. I use 14 gauge which gets instantly hot. I saw "Mr.Carlson" do it, but I think he uses 10 or 12 gauge wire in a small loop. Works great on cutting nylon rope so it won't unravel as well. I Can't wait to see the alignment. Great looking vintage receiver. Love that early 60's stuff!

[@MIKROWAVE1]

Yes a serious iron or gun. And brush it with a metal toothbrush add rosin and clean it up after.

[@p1nesap]

You recovered quickly from the effects of Bideneconomics 😂

[@thomashowe855]

Lol

[@MIKROWAVE1]

Barely!

[@georgehenly9340]

Thanks for posting this. I've been sporadically working on an S-120 refurb for a while. One thing that caught my attention on the schematic is that C13 (.005 uf bypass from screen grid of 12BA6) goes to chassis ground, rather than B+ ground. Is there a rationale for this? And even though C11 (.01 uf from bottom of primary of first IF transformer) is shown as connected to ground, the factory wiring on my rig has it connected to chassis ground. It seems like B+ leakage through either of these caps would tend to make the chassis "hot."

[@MIKROWAVE1]

They are attempting to make the IF stage (12BA6) act like a Q Multiplier and Oscillator so they are messing with positive feedback and they need a lot of RF gain, thus the cap directly to Chassis for the best RF ground. Yes if they break down leakage and bad stuff can happen.

[@ahchu3256]

I have experienced more noise on my AC/DC S-38 and NC-57M I attributed it to LED lighting conversion in the house. My S-120 was still very noisy after re-capping so I installed an isolation transformer and filtering on it. That helped some, but not a complete solution. DE K1TB.

[@MIKROWAVE1]

This was very disappointing to me. The noise is on the Neutral. I will be checking my house ground at the box.

[@michaelmiller641]

I had a hallicrafters S38b years ago, I did a conversion on it to a mains transformer with an EL 84 output valve, I'm not sure, in retrospect whether it was really worth doing! It wasn't the most fantastic of receivers!

[@MIKROWAVE1]

Did you learn something? I Bet it was a real project with a purpose.

[@clytle374]

Drill those rivets out and put in screws. You're right about the line to the power switch causing noise.

[@MIKROWAVE1]

A sound decision for sure!

[@BernhardOsthoff]

I have an SW-500 which is essentially the same radio. Noise is a commonly seen using this radio. That being said, when you have a strong enough station + good antenna, you can defeat that noise to a certain degree.

[@MIKROWAVE1]

Yes but it still drives me nuts when I can't easily solve a hum issue!

[@sgath92]

You can buy tubular woven wire shielding material that you can slip over a portion of the power cord where it goes near sensitive circuits, but then you probably have to put heat shrink over most of it so it doesn't short out adjacent parts.

[@MIKROWAVE1]

Wow that is a cool idea. Maybe we pop the lid and do some more work.

[@gretalaube91]

I fought a Wavetek 3001 signal generator that had a flaky rivet in the 1.2 GHz VCO of one of it's myriad PLL's. That was 40 years ago. Never trust a rivet...PTSD.

[@MIKROWAVE1]

Simply riveting!

[@mohinderkaur6671]

Definitely do not use headphones with these line connected radios. Regarding modifying S-120, I decided not to do anything. But if you want to, these things may interest you 1. add a rf amplifier with untuned plate resistor load of 2.2k using a 6ak5 2. add another 12be6 for SSB/BFO. 3. Delete the output tube add headphone only output or a solidstate amplifier using a audio chip- lm386, lm380 etc. This saves almost 10 watts of heat. 4. add a 12 v to 110v DC converter using a toroid or potcore transformer and a Royer or just 1 transistor hartley to power from 12v dc only. That takes care of mains isolation issues also. 5. replace 12be6 with 12ba7. regarding reducing noise try a long wire antenna in the yard away from interference into 9:1 or more ferrite core into a coax and back up to 600 ohms using 9:1 transformer

[@MIKROWAVE1]

Actually correct for many - but not this one. The S-120 design goes out of its way to isolate the phone jack and even the speaker.

[@bofor3948]

LED lights cause noise especially noticable when listening on shortwave. The items I have had the most issue with on SW are the plug-in ethernet extenders used to allow a faster more reliable internet connection than wifi. I tried them here in the UK and yes I could set up my PC or laptop well away from the router, but the mains wiring was radiating an amazing amount of noise that swamped part of the bands on my shortwave receiver. These unit can also radiate some distance over neighbours wiring if on the same phase. Hams and SWL's are going to have to invest more time, money and energy to eradicate noise to pursue their hobby as more equipment with lower quality controls is allowed to hit the market.

[@MIKROWAVE1]

Its not the LEDs themselves, but the PWM switching to dim them that makes the racket.

[@kennethandrysiak4130]

WHAT!! You say there is more line noise from all that fancy, modern electrical things operating down the line from the receiver then there was years ago?? Say it isn’t so. And further to the point… the wonderous AC/DC receivers are more susceptible to that junk? No surprise. Perhaps in your next installment you could demonstrate what, if any difference, there is when the receiver is plugged directly into the line vs. your isolation transformer. Decades ago, the ARRL handbook had a ‘brute force’ AC line filter schematic/parts list that could be constructed. Updating that design… perhaps you could construct something utilizing current materials and techniques (common mode chokes / toroids / etc) that would drown some of the junk on the line. I’m not sure how comfortable you’d feel constructed something like that… as it wouldn’t be Undertakers Labs ® approved. You might have to state a disclaimer. Thanks again for your interesting channel. 73s. KC9NAN.

[@LarryDeSilva64]

Oh yes humming and buzzing even coming from street lights the sodium vapor type. It was totally wiping out 80 meters. Took a month before the power company changed it. Even radio interference from a neighbors hot tub going on caused radio interference. Unfortunately getting harder to listen everyday.

[@MIKROWAVE1]

Yes I had this and have a noise cancellation article in Electric radio magazine that shows how to fight it. In the end I saw a lineman fixing a lamp about a block away and told him about my flaming blue streetlamp and he came right down and fixed it clean - I had been trying to get the power company to respond for months.

[@cpm1003]

Simpson Electric actually still exists. My company makes some stampings for them.

[@MIKROWAVE1]

Some actually survive but others just sell off the business and keep the name around - or actually just sell the name itself for royalities!

[@vincei4252]

I have solar and I've noticed that 80 meters is full of spurious emission equally spaced across the entire band. I'm not yet blaming the inverter but I'll be installing a second vertical antenna to see if the noise can be nulled.

[@MIKROWAVE1]

Well starting a search to find the source is the first step. Suppressing it there with a line filter, better grounding, shielding and ferrite Beads is next. Resorting to noise blanking and nulling is the final approach.

[@M0GLU]

I have a similar receiver RS-40 made in Japan. The original version is run with 120V AC. Mine is an EU version that contains an auto-transformer. In theory, the UK main plug is to eliminate the phane on the chassis. But I'm not happy with this. How can I mod to safety? If I install a separation transformer that provides the 150V AC and the tubes filament voltage (need to mod to parallel connection)?

[@MIKROWAVE1]

Wow an auto-transformer! How clever and cheap!

[@JCWise-sf9ww]

Yes, EMI interference on AM broadcast band is a real issue and something needs done to suppress or stop it. All the solid state rectifiers, LED lights and unfiltered Switching PS cause harmonics to travel on the AC main lines. Brush type motors can be real nasty with the hash from the arcing from the commentator. So the noise gets into the AM receivers two ways directly through the mains and # 2 through the air waves to the radio's antenna. The main lines to your house act as radiating antennas and transmission line for the EMI as well.

[@MIKROWAVE1]

I am starting at the Breaker Box. I think a lot is coming in on the main line. And what does my house ground look like? Of course you want to kill everything and test each circuit.

[@crxguy2006]

I love a good RF tickle

[@MIKROWAVE1]

Of course you would. ;)

[@misterhat5823]

9:00 You can take take the RMS of any waveform, not just a sine waveform.

[@MIKROWAVE1]

Very nice. But is it instrument technique sensitive?

[@misterhat5823]

@@MIKROWAVE1 Unless the you're using a true rms multimeter, the number you're given will be the average converted to the sine wave value mathematically. Therefore, your typical multimeter is accurate on sine waves only. Unless it says true RMS... Even then there's often a limited crest factor for accuracy. As for a sawtooth, there's a mathematical relationship between peak to peak and rms. Double check this, but I believe it's .575 times the peak to peak value that you measure on your scope.

[@Capecodham]

Can this be used to measure frequency for th ARRL frequency test?

[@MIKROWAVE1]

I don't trust them. I use a remote star decay method tied to the Webb Telescope.

[@Capecodham]

@@MIKROWAVE1 The Webb Telescope uses a Heathkit VF-1 as its internal clock.

[@sgath92]

I haven't been able to use much below 800khz for years due to noise problems, and not living in a rural area there's only so much I can do about noise. I can turn off all my breakers and it doesn't help if the neighbors across the street noisy electronics everywhere. Every year it seems like the worse it gets around 500-700 khz.

[@MIKROWAVE1]

That is a tough situation but all to normal now. But it is worth investigating to see if some can be mitigated if it disturbs your listening situation.

[@vincei4252]

wouldn't the cork between the front panel and the chassis just behave like a gigantic cap for AC ?

[@MIKROWAVE1]

Well, for 60 Hz, it is still small, perhaps 100pF . And we already have the deliberate cap of 0.01 to 0.047 uF, which is considered safe.

[@mnoxman]

You can clear up some of that with a line filter.

[@MIKROWAVE1]

This is where we went with the video series.

[@erikburman530]

Wait. I'm confused. You say you brought the ground through to the other side? Doesn't that defeat the purpose of isolation? The earth ground is tied to the neutral side at the main panel buss bar so that the neutral side is referenced to earth. By connecting ground to both sides aren't you defeating the purpose of isolation? I mean you are basically connecting the neutral side of the line through to both sides. So neither side is isolated from the other. Or am I not getting this right?

[@MIKROWAVE1]

Once you go though the transformer, you get protection and no current can flow from the input PRIMARY ground - PRIMARY Neutral or to PRIMARY Hot to either lead of the secondary.. But once you attach a ground to the chassis or the case, now at least the set is referenced to ground, which is as safe as you can get in the shack.