S-120 Alignment - Changing Caps A Waste?

In Part 3 of the S-120 Refurb, we do an alignment of the set. And as a BONUS - a capacitor reveal section inspired by K1OIK.

[@josephsawicki9335]

Mr, Carlsons lab has a great capacitor tester you can build that can even see future failures of the caps,Incredible channel to watch tune in to see how to build one, Great video on here too thanks.

[@W1RMD]

Those circuits look fairly simple to build. He's got a couple different variations and mentions one with a jfet, but I don't see a schematic for it. The one with the bipolar transistor input looks so sensitive that you shouldn't need a jfet. Have you tried any of these circuits yet? I was thinking of making one with some basic parts. Most of the time I just replace caps that are questionable anyway, but it would be fun to build.

[@Capecodham]

I can't stand Mr. Carlson.

[@MIKROWAVE1]

See! He Likes me!

[@Capecodham]

@@MIKROWAVE1 Of course but Paul Carlson is totally into self, you are genuine. Carlson can take a one-minute story and make it into ten.

[@W1RMD]

Great job explaining hours worth of info in less than 1/2 an hour. Nice little receiver to work that well on 15 meters. According to the results of your last video, touching the case of a transformerless set is safer than petting a wolf. Thanks for your time.

[@MIKROWAVE1]

We are into the sunspot cycle and 15 is waking up for longer and longer during the day. That is mostly it. Oh and frame the selfie shot honey. That wolf looks so nice next to the kids.

[@calescapee9642]

I have one of those.Also have two SX 99s,an S20R Sky Champion,a SX111 and a National NC 125 plus Various other Old Sets. Cool Stuff.

[@MIKROWAVE1]

Old radios smell nice too. Well except for the British R1155 I got that was full of mouse droppings.

[@ellise.2574]

Hi Mike. Thanks for a very nice video. While repairing my BC348 a defective micamold cap fried a resister in the IF. luckily the IF can was OK. I wound up replacing all the micamold bypass caps. A bad cap can do real damage to hard to replace components. Thanks.

[@MIKROWAVE1]

I have had a lot of WW2 surplus go through my shack! Everything was pretty good until the early 2000s, when all of a sudden, I started seeing cap failures. Everything has a ln MTBF is guess.

[@basspig]

I have a draw full of New Old Stock bumblebee caps that are at least 65 years old and nearly all of them leak considerably. Some of them even have split along the seams where the two halves of the molded case are fused together at the factory. I figured that once they split they absorb moisture and their leakage goes up astronomically.

[@MIKROWAVE1]

I recapped a WS-19 from 1942 missing covers laying on the ground holding a tarp guy line. Oh it was in bad shape. But the 20 or so 0.1 Wax Sprague caps that I removed were all still handling 450V and pretty good for leakage! Wow.

[@ahchu3256]

Great video. Just adjusted my BFO as you demonstrated. Now I can copy some sideband and CW sounds better too - DE K1TB

[@MIKROWAVE1]

It's kind of across between a regenerative IF Q Multiplier and and a BFO, doing neither well!

[@mikebracey8832]

Mike, Would you make a video on your command set transmitter modulator? Your past command set videos are great.

[@MIKROWAVE1]

I can dig this up.

[@harryshector]

I think leakage is particularly an issue with tube devices. Tubes are very high impedance devices, and so those uA leakage currents can translate to dramatic changes in grid bias when couplers are leaking. This can be very hard on tubes. Not to mention output transformers and the like. It would be interesting to be able to see how the capacitors we are installing today perform in 60 or 70 years. they probably won’t show the degradation evidenced by the old-timers of today… But, I wonder if they’ll be as tiger-tight as they are now?

[@MIKROWAVE1]

Its mostly a slow degradation over time until the receiver gets shelved or put in the attic or garage for total demise at a later date; usually after the flea market and you get it home!

[@gretalaube91]

Mr. Graff (TV repair guy) taught me long ago to look for the "shiny" (hot) ones. Also look at the bottom cover for wax drippings or marks. Audiophoolery- Leakage isn't a bug, it's a feature.

[@MIKROWAVE1]

Those old TV Radio repair guys were the real deal.

[@robertmeyer4744]

That was great. The one I have is much older. the S-36 receiver.has acorn tubes in front end.did not work when I got it. estate sale . lots of dust on it. had to totally re cap and some resistors change. when all done quite a receiver .may be even better than new with better caps. had wax mica ones in it. some cracked in half. 73's

[@MIKROWAVE1]

Yeah when they Crack in half, that is a sign all right!

[@sgath92]

I think a lot of the debate on replacing caps boils down to what the future of the radio entails. If its going to be owned/operated by someone with little electrical knowledge, it makes far more sense to replace them all "while you're in there" than have the owner/operator turn around with a problem 6-24+ months later (the real cost of a restoration is the labor, comparatively caps are almost free). And for the people with the knowledge & time, there's a strong argument to be made for doing it all at once to avoid having to go back in so that the chances of a problem are minimized, to maximize time for knocking out more projects. Seems a lot of radio enthusiasts have a lot more "to do" than stuff that is "done." Enter: "All radios work, that's a phrase I have not heard in some time" memes.

[@MIKROWAVE1]

"Original, Unmolested and It Works" can mean many things as you squint and turn the radio on hoping that the magic smoke stays in one more time!

[@DAVIDGREGORYKERR]

What about using 3x 12AU7 tubes in a cross coupled double balanced mixer like the SO42P but using the 12AU7 vacuum tubes and you could use that third tube as a local oscillator and for ideas you could have a look at the SO42P datasheet for more ideas.

[@_wave64_]

I routinely rip out the silver mica wafers from the IF cans and replace them as well with ceramic disc capacitors

[@MIKROWAVE1]

It is getting this way with the tub caps in the old Command sets too. They are all failing now.

[@JCWise-sf9ww]

If the old cap in a set tests for no leakage and is within tolerance, you can leave it there or is it risky to leave it in or replace it for ensuring longevity? Guess it's up to how you think what is best. I recently been restoring, a hardly ever used, 1970's DeVry oscilloscope and just replace the caps that tested bad the rest tested ok with no leakage. So sometimes you don't need to replace them all lock stock and barrel. (BTW: I did replace all the 20uf 450vdc filter caps as insurance.)

[@MIKROWAVE1]

Yes I agree - it's a no win emotional battle between good enough stock - and fix it to the point of non historic...

[@MIKROWAVE1]

And if you are just flipping it - who cares anyway? The red lamp came on! All good.

[@kwacz]

but now that you put the radio back in service will they be leaky in a year or two?

[@MIKROWAVE1]

Ha! Those electrolytic caps that were put into radios in 1960 probably started to leak after 30 or so years. Modern caps should last at least as long. If in doubt, go for a higher voltage rating than what you replaced.

[@kwacz]

@@MIKROWAVE1i meant the old ones that appeared to be good that you left in there. I tried reforming caps a few times in old sets and they initially tested good on a cap tester but then some failed a few months later. Just saying change them so they dont fail later and take out other parts.

[@MIKROWAVE1]

@kwacz shotgunning all the caps is done and some folks do this. I did this with a military radio from 1942 with almost 30 0.1 uF 400V paper caps. Then I tested them on my cap hi pot and leakage tester. 3 were bad. In other radios they all are leaky, but the set still works! There is only one approach that guarantees- shotgunning all of them. But there are folks who are dead set against this practice.

[@G7VFY]

If you replaced the noisy carbon resistors with quieter metal oxide, do you thing you would hear a difference. G7VFY

[@Capecodham]

Noisy?

[@G7VFY]

@@Capecodham Yes, noisey

[@migsvensurfing6310]

Not on a shortwave receiver. Higher frequencies like vhf/uhf yes but not a lot gained.

[@Capecodham]

@@G7VFY Cite your proof.

[@MIKROWAVE1]

Hmmm replace all Carbon Resistors...Reduce carbon emissions. I could sell that.

[@ricke.2205]

Premieres rule. Thumbs up.

[@AdamosDad]

✋73's🎙KD9OAM🎧📻📡

[@Capecodham]

You wasted a lot of time "aligning" a receiver without checking how it worked before hand. I didn't bother aligning my S-76 when I compared it against an Elecraft K4. You used a 1000-year-old capacitor meter to check capacitors, the test equipment was aligned itself only 60 years ago. The older capacitors had leakage so small you had to dig up a microamp meter to measure it. Would you replace the engine in your car if it produced one percent less horsepower than a new one? Wholesale re-capping is foolish. In fact, I had a S-76 whose filter capacitor belched steam and smoke, I was going to replace the capacitor until I turned it on after the capacitor cooled down and has been working fine since March. Humming right along. For those that don't know Morse code, Mike took liberties with the translation assuming the viewer was too stupid to know what 73 meant. Mike however did not translate the FT-8, but I heard one ham give a -18-signal report from Austria.

[@migsvensurfing6310]

Are you having a bad day ? What he did was perfectly fine. Try to learn ohms law. Microamps and megaohms on the grid gives volts of bias error.

[@johnnytacokleinschmidt515]

I think he made a joke. He said after the capacitor belched smoke he turned the set off and let it cool. He says it's been humming right along since....😂 The rest he sounds sincere and displeasurable.... 😮

[@Capecodham]

@@migsvensurfing6310 How much? micro, micro, micro volts? I believe in K1OIK's law, "if it ain't broke, don't fix it."

[@PeopleAlreadyDidThis]

Classic K1OIK response.

[@Capecodham]

@@PeopleAlreadyDidThis Mike is real and genuine unlike Mr. Carlson's lab, the is so much in love with himself he refers to himself in the third person.