#95 National NCX 3 Repair Part 1 Blooper to follow

This is part one of the National NCX-3 repair. We replace some capacitors and check out the receiver.
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[@PapasDino]

Good of you to share the blooper...excellent demo of the fact that there really is such a thing as "magic smoke" and that it in fact can be let out. We learn from our mistakes and the young guys got to see what can happen w/o the pain! 73 - Dino KL0S

[@TheRadioShop]

That's right Dino. In a way glad it happened. Don't want folks think I do not make mistakes. I have edited out so many lol,

[@ve6svj]

Thanks for this video. I got an NCX-3 a while back but it's in rough shape and I'd like to get it back to working order... when I get to it, your video is going to help a lot.

[@RGB06084]

Funny stuff with the exploded cap Buddy!

[@Beretta96Dan]

Hi, Buddy! I had one of those rigs around 1973-1976. Loved it, but it didn't love me. I could not tell you what ever happened to it. I think I just gave it away. I had just finished a QSO with another ham, and when I went QRT, I didn't turn off the radio. In a few seconds, another ham started a QSO with the fellow I was talking with. He asked who I was. He told him, and after that he told the dude I had been talking with that I had the worst audio he had ever heard on ham radio! Lol! I got pissed and got rid of the radio, and stayed out of ham radio for a decade. Eventually got another radio and have been enjoying it since. Good luck with that rig, and let us know how it works for you in an update. I think my radio had a balance modulator problem not that I think about it. 73...Dan w4mnc

[@TheRadioShop]

Dan, Thank you for sharing that interesting story. I have heard similar stories like that with National rigs. Plugging up the mic jack and using a key makes it sound so much better :)

[@billpowell5931]

What a great video! I enjoy watching a master passing on troubleshooting and restoration tips and such. Thank you very much for sharing. Haven't restuffed a can yet, but I will eventually. Your guidance and experience are good confidence builders.

[@DonDegidio]

Hi Buddy, That blooper just shows you're human like the rest of us. The volume pot, I wouldn't be surprised Mike could assemble a new one with the parts he has available as shown in some of his videos. HiHi 73 WB3BJU

[@TheRadioShop]

Yep, happens to us all. And already talked with Mike about parts for the control. Thanks Donald

[@jeffminnick5209]

Another amazing video presentation of a cool boat anchor... also liked the oops with the cap at the end....note to self, when yu write it down.... read it....hahaha .... love your videos and rank you right up there with Peter @ TRX Bench and Paul @ Mr Carlson's Lab... Im a tinkerer as well although mostly musical gear related but also a ham .... you get the idea 73 my friend Jeff WD8JM

[@jaybats7865]

Nice rebuild Buddy man it’s looking good and working top notch now. It’s just awesome how you systematically go through the equipment and take care of EVERYTHING I love it. Happy days my friend 👍

[@rollerbald]

Interesting video Buddy. I always liked the clean look of those National rigs. In a way they remind me of my old Swan 240 (80-40-20 meters), not so much in looks, but in the way they operated. 73, Bill.

[@TheRadioShop]

I have forgotten all about that model of Swan Bill. Yep works about the same.

[@franciswhite123]

That's great! I've "let the smoke out" a few times myself. I am continuing trying to make my own NCX-3 a little better. Thanks for sharing. I will be watching for Part 2!

[@TheRadioShop]

Thank you Francis. I will be working on part two soon.

[@pierrelataillade7564]

Thanks for getting me hooked on your channel.... I'm a Yeasu fan, and literally cried when the 101 series crashed. I love my EE and you have resurrected my interest in this regard. Please note that I have a huge interest in your presentation. You sound almost like a friend. Thank you for sharing your knowledge... 73s

[@TheRadioShop]

Thanks Pierre for watching and glad you like the channel. I promise to get back on the 101 series before too long. Thanks my friend

[@kardeef33317]

I am new to tubes so I might be completely wrong.I was watching Mr. Carlsons vids I think and I think he mentioned old caps measuring in spec , but still passing DC and loading up the tube. Still learning and trying to help..Keep the great vids coming and thanks for sharing your knowledge.

[@TheRadioShop]

Yes a capacitor can show good on a meter, but can leak and have high ESR. Equivalent series resistance. In other words it acts like a resistor. Thank you and thanks for watching.

[@wb8cxo]

Buddy, LOL with ya not at ya! Most of us have done this... the rest will someday if they dare try to fix electronics. Thanks for sharing! I learn something with every vid! 73, Mike

[@TheRadioShop]

Thanks you Mike. I knew just what I had done when the smoke came out.

[@badass4226]

love your vids. Keep them coming! Thank again.

[@TheRadioShop]

Thank you very much Mike

[@roccolardiere6992]

Wonderful video. Could not find Part 2, yet. A couple of comments: I found a plate amplifier cage on the very similar NCX-5 with a formed area on the top that fixed the tuning cap clearance problem. National knew that the design was not great. In operation, though, when you properly tune the NCX-3's and NCX-5's, you just don't short out that cap with the circuit values they chose. It's not really a problem, even with the flat cage design.. As for the alignment instructions, consult pages 13-17 of the manual. They are very complete, but these alignments are not for beginners. I loved your meter repair section. I failed twice to find the intermittent problems on identical meters, and you found the issue and fixed it on yours. Very nice work! 73, N6KN

[@TheRadioShop]

Hi Rocco. I have not had the time to get to part two yet. So busy with folks radios I have put a lot of my stuff on hold. Interesting on the formed cage design. I know the top cover to cage clearance is extremely tight on this rig. I also found an original manual so have all the service notes now. Yeah the meter was a snap. Seen this so many times. Thanks for stopping by my friend.

[@roccolardiere6992]

I am looking forward to Part 2. I want to see how you perform the alignment. I found it very challenging, although my radio sounds great, now. 73!

[@davidlegault9745]

Great video Buddy with an exciting finish. Regards, Dave

[@TheRadioShop]

Thanks Dave

[@judges69]

Man would i love to find one like this, am retired now and would love to do this. In Canada there is not mush available up here and ebay cost a fortune for shipping. love you videos, your one of the good ones on youtube.

[@TheRadioShop]

I surely hope you can find something one day my Friend. You just may b ever know where something can turn up. Thank you very much for the kind words.

[@injoelsgarage3934]

Buddy, Nicely done. even the blooper. if someone has never done this they will at some point. Sh@t happens. waiting for part 2. Also waiting for the finishing video on the fender amp. You take care of your self and get well. Thanks for Sharing! Joel

[@TheRadioShop]

Thanks Joel. Working on part 2 and the Fender this week.

[@larrysherwood9]

Looking forward to the next episode. Makes me want to drag my Swan 270 and 250 out and get them back up and running.

[@TheRadioShop]

Thanks Larry. I like the old Swans also.

[@larrylacroixve3oei489]

Ah!! Don't you hate it when you let the smoke out... lol. Great video. I really enjoyed it..

[@TheRadioShop]

lol. Thanks Larry. Now if I can get it all back in the cap.

[@vetterfellow]

Welcome back Buddy; Your sounding much better, except for the phlegm. We've all been there. The sounds of recovery. Maybe your clutter problem can be solved by a crash cart. You know like a dinner tray on wheels. Just a thought. Great video again.... TTFN.

[@TheRadioShop]

Thanks very much my friend

[@Homer19521]

I worked on the meter on a SX-100 (as recall) & there was 274 volts on one terminal to ground. I got very surprised by that. Luckily, I had one hand in my pocket. I'd recommend checking voltages before handling the meter as you did.

[@TheRadioShop]

That is a good point Bob. But 274 volts on the meter? Will have to pull the schematic on that one. Crazy voltage lol. This one has a peak of 3 volts DC on it.

[@cuban9splat]

I had to laugh at your blooper because I have done the same thing. It just proves you are human too and I WAS beginning to wonder if you were human after watching your videos. Was beginning to think you must be super-human because of all your excellent skills and knowledge! Sh*t happens to all of us. Although it seems to happen to me more often than most LOL. About the negative pole corroding before the positive, I believe it is because the negative is the source of the electrons that flow in an electrical circuit and having two dissimilar metals involved. I could get into a lengthy explanation but it would confuse the crap out of me and everyone who reads this comment LOL.Great job on the video Buddy! Thank you for sharing it with us. I love seeing old girls like this National transceiver get brought back to life.73 DE K7RMJ Frank

[@TheRadioShop]

Thanks Frank. Well through the magic of KZbin (and EDIT) you guys rarely see the mistakes he he. Most of the time the videos are just shot and what you see is what I see. But this one was so funny I had to move it to the end. You are spot on to the cause of the terminal corroding. Well done.

[@mikesradiorepair]

At least it was only the 25 volt cap. I popped a 100uf 600 volt cap about a year ago in a amplifier. Was one of the ones where they run 8 caps in series parallel configuration to bump up the voltage and value. Somehow hooked up one backwards. Took it about 30 seconds, I heard a short whistle as it started to vent and then BOOM!!! Let me know what type and value that control is. I can probably build a new one for you from my IRC Spectrol kit.

[@TheRadioShop]

Bet that made a big bang lol. Hope your hearing is ok. Going to try and get back on it this week. Will let you know. Thanks Mike

[@SkyWire88]

Very nice CQ calls. I may capture and use your technique, OM. And a very nice video on your long wire. 73, Earle

[@TheRadioShop]

Thank you very much!

[@jeffalessi]

Totally Awesome

[@TRXLab]

Nice radio Buddy. and we all let caps blow :^) Thanks for the enjoying video! 73

[@TheRadioShop]

Hi Peter. Yep had to show how to blow a cap lol. Thanks for watching and 73

[@gh778jk]

The simplest way to solder to those aluminium leads is to copper plate them. This is very easy... a teaspoon of copper-sulphate in a glass or warm water, a DC voltage , say 2 or 3 volts and a piece of clean copper wire... Plate as usual, rinse and repeat when more than one is needed It will readily take solder after that Paddy

[@davidelsea9938]

It's nice to see that you really are human Buddy. hi hi

[@alankessel8891]

Too bad I’m just now watching this video because I have the National NCL2000 amp that would go nicely with your radio!

[@TheRudydog1]

Thumbs up man!

[@kd2eat]

It's SO tough to get the magic smoke back IN after you let it out! hehe

[@TheRadioShop]

You got that right

[@MDFRESCUER]

Good video.

[@TheRadioShop]

Thanks

[@bundylovess]

Nice video buddy . You wear just showing us how not to hook up caps lol I did something similar once and coped capacitor guts in my face that's suff don't taste nice . Big thumbs up my friend

[@TheRadioShop]

Had to show the correct way to blow a cap :-). Thanks allan

[@waynecarlson3736]

Buddy Good video Thank You

[@TheRadioShop]

Thank you Wayne

[@mikesmithg0rfd356]

i have a national HRO mx it with a lot fun

[@larryk4mu240]

Hi Buddy, Great video, love the blooper. I reached over and picked up a 25v electrolytic instead of a 350v not noticing and it vented when I turned it on. I did not have the pop but I had plenty of smoke! :>) Many good tips in this video, interested to see how you solve the cap and cage issue. I assume you have the instruction manual with the Test and Alignment procedure starting on page 13. If not I have it. 73

[@TheRadioShop]

Thanks Larry. Funny how that tiny cap pooped so loud. guess 360 volts was a bit much for it lol. I happened to find that manual this afternoon. Never seen this before until today. Not written the best but will work.

[@w.rustylane5650]

Negative side corrodes because of electron flow from positive to negative. I just got my General Ham license upgrade and have a Kenwood TS-430S and PS-430 power supply. If I want to engage a repeater on 10 meter band, how do I use a CTCSS tone on the repeater since my Kenwood does not have any CTCSS tones??? 73 from K9POW in eastern Tennessee.

[@jeffreyprater3093]

I have just been given an NCX-3 and want to refurbish it. I've enjoyed watching your Part 1 very much. Is Part 2 available now, and if so where can I find it?

[@TheRadioShop]

Have not had any time to get to part 2, soon I hope.

[@AF6LJSue]

Good Stuff.

[@TheRadioShop]

Thanks Sue.

[@jaybats7865]

So what ended up happening to the gain capacitor hitting the top of the cage? Did you rotate it to keep from hitting the cage or some other fix? Thanks

[@rasputinputin8103]

The negative corrosion is caused by the cathode being adonic to the brass.

[@MichaelLloyd]

Backward caps must be a 2017 thing. I blew my first electrolytic, because I installed it backwards, this year. I'll take a stab at the corroded meter terminal question. Current flow is negative to positive and the dissimilar metals of the bolt and tab sets up a corrosion cell. Galvanic action at work. Metal leaves the brass screw and oxidizes on the metal tab. I used to work with cathodic protection for pipelines and I'm dragging old memories out so I hope I'm at least close

[@TheRadioShop]

Very nice explanation Michael, Well done.

[@MichaelLloyd]

We use a large rectifier to "pull" the pipeline more negative (DC). The worse the coating on the pipe is the higher the voltage impressed on the anode(s) will have to be. The anode(s) for the rectifier is/are either buried in a deep well (to cover more distance or to put them in an electrolyte, which means soil with minerals and water) or spread out perpendicular to the pipeline and buried in a ditch which is then backfilled with cokebreeze. The pipeline is the cathode which is why they call it cathodic protection. If two pipelines cross each other and there is a difference in potential we have to bond them together otherwise the line with the higher (more anodic) potential will begin to lose metal. Sometimes at an alarming rate.

[@YouAllKnowBob]

Hey, at least the vent hole worked! ;-)

[@TheRadioShop]

Guess this was a good way to test it lol :)

[@jemasons]

...for the same reason that Ma Bell reversed the polarity on copper phone lines and steel ships have a copper block on their keels...galvanic action.

[@TheRadioShop]

Bingo!

[@dhpbear2]

33:19 - a built-in keyer! How was the tuning-capacitor issue solved? It appeared to me that it was fully open and NOT hitting the cage (?)

[@TheRadioShop]

I was able to raise the cage about 1/8 to get it to clear. After this video I had several folks mention about shorting out their capacitors on these.

[@dhpbear2]

Sounds like a MAJOR design flaw!

[@PaulHigginbothamSr]

its electrolysis boyo, and is recieving electrons from the circuit to corrode.

[@albertmorris4889]

Not a fail, just a demonstration that voltage ratings are for real. Do NOT go over the stated voltage. HI Maybe we can do some CW someday. 73

[@TheRadioShop]

Good thought process Albert. And would enjoy that my friend.

[@dennisqwertyuiop]

very good work,adding longer leads on var cap would that change anything ? I know you know what your doing thank you for video

[@TheRadioShop]

Hi Dennis, Yes it will. So we would have to compensate for that.

[@4X1000]

Well, these bastards can be real nasty if you use those with working voltage less than what is in the circuit lol! Nice job as always! 73's de SM2GXN

[@TheRadioShop]

Yep, that was a mistake lol. Thanks.

[@GrandsonofKong]

I've never wired a cap to the wrong voltage or or gotten the polarity backwards...well today that is...and it's still early!! :-) Question: On your new Power Cord, you didn't show the finished product but I assume you wired the Power Line Ground to the Power Supply Chassis as well? Good video!

[@TheRadioShop]

Lets hope you keep that track record!Yes It was a new three wire cord. Plan to cover that part in part 2 along with installing safety caps. Thanks

[@InssiAjaton]

I would avoid blocking the pressure relief port area with any hot melt. Maybe you did not apply that much -- hard to tell from the video. Anyway, I have witnessed one explosion of a log life capacitor (long life means extra amount of electrolyte) that had been mounted in reverse. Was way back in 1960's but the bang still echoes in my mind.

[@TheRadioShop]

That is correct. A hole is provided in the bottom of the assembly to out gas any pressure. Also at 32:08 you will see I talked about an added hole in the top of the capacitor to relieve any built up pressure.

[@jonka1]

@18:02 this goes way beyond a design flaw. If I hadn't seen it here I would not have believed it possible that a manufacturer was capable of producing such a mess and selling it to the public.

[@TheRadioShop]

agreed!

[@ozloon2000]

the only thing that worried me with the ncx3 and ncx5 is the relay operating to Receive Ron VK2MU

[@TheRadioShop]

Interesting. I have not seen this issue. Thanks

[@ozloon2000]

@@TheRadioShop its not an issue its haw they operate the relay closes to receive

[@Scott-K7sce]

trivia question answer:: in my case the - corroded do to the mismatch of metals and the conductivity difference. thus my neg terminal corroded rather quickly and had to do some replacements of the battery and the terminals got new cables with pigtails, soldered the leads from the ham radio and the pigtail connected them together with a connector not had any issues since. :-) LOL @ the blooper. 73's k7sce

[@TheRadioShop]

Good reply Scott. Thanks

[@Scott-K7sce]

on the mesh. you could use a dremel, grind away just enough to have clearence. ????

[@TheRadioShop]

You could but it will change the capacitance quite a bit.

[@gerhardwagner9539]

Curious about part 2, but couldnt find any video. Did you give up on fixing the transmitter portion?

[@TheRadioShop]

Have not gave up. The radio works fine as it is.

[@gh778jk]

I have the 'corpse' of one of those 'digital' Nationals... you know the one with the 'odometer-frequency-indicator' It was given to me years ago. The transceiver was so 'golden-screwdrivered' that every time I want to start it's resurrection (Trust me, this is biblical, no simple restoration) I open the transceiver, close it again and do something else. A pity really, it is quite a novel thing. Paddy

[@TheRadioShop]

Oh yes. I know what you mean about that. I hate working on those types.

[@rubusroo68]

do bleeder resistors across capacitors always draw current or only when the device is shut down?

[@TheRadioShop]

Yes they do. But the resistance is very high.

[@jonka1]

The bleeder resistor is connected across the cap and therefore always passes current. It is not switched and cannot know if the receiver is on or off.

[@bogywankenobi3959]

at 18 minutes you say that the pa tuner cap has an insulated rotor and grounded stator. Can you explain why and how the rotor is insulated? Doesn't it turn on bearings that are mounted in the frame which is grounded? And wouldn't that ground the rotor. This is backwards to every variable cap I know of.

[@TheRadioShop]

You are correct, My mistake as I said it backwards. I will edit the video tonight with the correction. Thanks

[@jeromegrzelak8236]

smoked the cap dont feal like the lone ranger

[@donaldjones6335]

this is set up like a swan 250 same inside

[@TheRadioShop]

Very similar yes.

[@kardeef33317]

Electrons flow from - to + ?

[@TheRadioShop]

You got it.

[@brianumbrell5654]

Electrons flow negative to positive.

[@jonka1]

Sorry to be picky but is there any chance you can start saying signal instead of single?

[@TheRadioShop]

Not being picky. Just an old habit that has been hard to break.

[@GardenBushcrafter]

Any update or sequel on this video?

[@TheRadioShop]

Not really, after running the rig for a while I found that it is doing a pretty good job on ssb. About the only ting I need to do is fix it so the variable cap does not hit the top cage. Been so bust I have not had a chance to get back to it.

[@GardenBushcrafter]

It would be great to see how the NCX-3 is running now. There seem not too many videos on youtube that NCX-3 is at actual contacting other stations on air. Thanks.

[@theradiomechanic9625]

Buddy, I am sure you know this and were aware of the rating of the S-Meter you tested. You should mention that testing Analog meters with an analog Ohm Meter can destroy the meter movements. Many analog VOM's pass as much as 300 mA through the leads on R X1. Most exceed 100 mA. Should you get across a meter movement that is 50 uA or 100 uA you can instantly blow the movement. I always tell folks to NEVER test meter movements with a VOM unless they absolutely know what the movement is rated for and what the Ohm meter is producing. I actually have stickers on my meters telling me what each one produces on each ohms range. By the way, popped a few caps myself.

[@TheRadioShop]

You are right. I should had mentioned that. I know this cheap meter is very low and the meter is well above 150 ma. I will cover that in part two. thanks for bringing this up my friend. It is very important.

[@PapasDino]

Alan W2AEW did a nice job of describing meter movements and how to measure a meter's current handling capability...see his episodes #235 and #236 over on his channel.

[@TheRadioShop]

Yes they are very good examples Dino. I really enjoyed those and use that quite often.

[@1Rowdy1derful]

Ever work on a drake?

[@TheRadioShop]

Yes, Been a while but have repaired a few.

[@1Rowdy1derful]

Just wondering if you had any videos of working them. I run a couple of TR4's and a pair of the twins (R4-B, T-4XB). As well as my heathkit gear, SB 102, SB 400, SB 401, And all the speaker units and power supplies. All together makes one big pile.

[@TheRadioShop]

Oh yes, not much I do not work on. In fact I have a fully working TR-4 on the way. Will be doing a restore video on it in the future. You do have a "heavy" pile there my friend. I do not currently have any videos on those. Sometimes locals come in for a quick fix and I do not record the repair. Only when it is left here.

[@1Rowdy1derful]

Ha; I'll have to be sure to watch that. See how many hints I can pick up from you. I just picked up my second TR-4 to go in a jeep, and it's all original, set for most of it's life, and pretty rough, Lot to do to restore one in that shape. Hmm maybe I should make a video on that. I've thought of making a video on several things but just can't seem to find the time to do it. Besides being too damn ugly.

[@TheRadioShop]

Cool deal. Yes do a video on it. You are going to repair it any way. I seldom show my ugly mug. Anyway the video is about the repair and not the person :-) About all my repairs are on video. Some never make it to KZbin.

[@rparker4843]

Hello name is rex W5mpg I have my dads old hro 50

[@rparker4843]

Hello buddy merry Christmas do you need some old receiver manuels I have a lot of old books and repair books and a collection of some books from the chief engineer of wsm radio in Nashville tenn look me up at W5mpg on qrz

[@wa4aos]

PART 2 ?????????????????????????????????????

[@Dave5783]

bloooper...lolololo it is a diode hahahahah

[@TheRadioShop]

BooM!

[@paul.alarner6410]

wait 5years and see if those iffy caps fail,mind you cheques cleared by then! lol

[@MrBugsier5]

making mistake's is only human! lol

[@TheRadioShop]

True, and we will make more :)

[@lupojacobo9892]

I'm sorry but I will never understand the obsession of restuff old capacitor..

[@TheRadioShop]

I replace more than I restuff. But it is sort of a trade off. Sometimes stuffing it is convenient. Other times the owner wants it to look original.

[@Dave5783]

Or a flux capacitor...lololo

[@TheRadioShop]

ROFL!

[@paublusamericanus292]

snort giggle. oh buddy!! anyone can make a mistake, and we are all humans, just that I make way too many, like not buying bitcoin at 1:00$

[@TheRadioShop]

LLOL, yep happens to us all.