How to replace a Vintage Ham Radio power transformer National NC-173

This fine receiver came to the shop in need of a new life. Normally these units are in poor cosmetic condition. This ones a solid 8, well worth restoring. As you can see, it is quite the undertaking if you do not have the original type transformer. Lucky D-lab has a mill in the shop. Makes easy work out of chassis modification. If you have one of these radios and the original transformer is installed and operational, word of advice, change the filter cap and those negative bias caps! A little preventative maintenance will save you a world of stress & work. As always, D-Lab changes out caps on all these old rigs that enter the shop. They have done a great job for 50+ years. They will last an easy 50 more with TLC. Thanks to all that have been supporting my efforts. This piece was purchase with donation funds, so you can enjoy the results.

[@preiter20]

Great video Terry! Love the troubleshooting of the cause of the initial failure.

[@kornami8678]

Dad had a NC-173. I loved it. Wish I still had it.

[@materialsguy2002]

Nice work, Terry. Great to see the National rx working again rather than scrapped. 👍🏻

[@83roadstar]

Love the vertical mill for projects needing machining! Great vid Terry!

[@d-labelectronics]

Yes Sir, very handy instrument

[@drtidrow]

Seems like overkill to me, when a sheet metal nibbler would work just as well.

[@daleburrell6273]

@@drtidrow 1- THAT'S TOO MUCH WORK, AND 2- IF YOU HAVE THE EQUIPMENT, USE IT!!!

[@rciancia]

Terry, that radio chassis looks like a first cousin to the Hammarlund HQ129x.. What a great job retrofitting the new transformer.. and even better job finding the root cause... that sets you apart from alot of other folks I watch... well done my friend. P.S... You may want to check my latest video... LOL

[@8xlaxx]

Great video Terry! Keep them coming.

[@themongoloid8944]

You seem like good people Terry, if you ever drive through Cincinnati or Corbin, KY. Give me a shout and I will buy your dinner if I am in town. I am waiting for some mulberry wine from a friend of mine, it’s like nectar from the gods. I will send you a bottle when it’s ready this year.

[@SteveHacker]

Fantastic video as always! Always something new to learn. I just wish more actual “how to” was shown instead of just “here’s what I did” (after the fact) though; longer videos with less editing (which would actually be easier to make - less editing, less labor time) and actually showing more “how to” would be amazing. And remember, boys and girls, “EK-specially” is not a word; not in any language, region, dialect, accent, state or nation... LOL! 😂😂😂

[@wolfhawg]

Great job Terry.

[@javierbiaggi3072]

Beautiful job, its looks like factory.

[@Justplast]

Good Job

[@sennevilleeify]

New to your Channel. Great work great guy great familly and surely great wine

[@АлександрТом-щ6ю]

Благородное дело... Спасибо! Привет Вам из Москвы, UA3KBD (60 годы..)

[@crosleyfiver8686]

Really enjoy your posts.

[@JWimpy]

Good idea using a mill. I miss having access to a lathe and mill. But I retired.

[@daleburrell6273]

...NOTHING SAYS THAT YOU CAN'T HAVE YOUR OWN MACHINE TOOLS-(!)

[@JWimpy]

@@daleburrell6273 IF ONE HAD THAT KIND OF MONEY.

[@daleburrell6273]

@@JWimpy ...THAT'S THE TRUTH- AND YOU'D NEED A DRY PLACE TO KEEP THEM: A DAMP BASEMENT IS A DEFINITE NO-NO!! I KNOW EXACTLY WHAT YOU ARE TALKING ABOUT-!

[@JWimpy]

@@daleburrell6273 Yeah, didn't think about the dry area. My workshop is a back room of my barn. It gets very humid in there being in the South.

[@evananderson8452]

Another great job

[@geoepi321975]

you are great amp doctor

[@msaradio7455]

Awesome Terry, 73.

[@fabinhoosmar]

Mais um bom trabalho colega. Parabéns !!!!!

[@renegade44040]

Oh yeah broke out the milling machine. A milling machine will fix anything 🍷

[@douglasjude714]

i realize I'm kind of off topic but do anyone know a good website to watch new tv shows online ?

[@daleburrell6273]

..."IF YOU'VE GOT IT- FLAUNT IT"-(?)

[@RobertKohut]

Nice!! Great work... :-)

[@DeadKoby]

The average nerd would be trimming that cavity with a dremmel tool. A super nerd owns a bridgeport.

[@ZenithClarity]

I keep wishing for one of those. Hows it go? Wish in one hand and ...

[@lwilton]

You could do it with a $9 saber saw with a metal cutting blade and a hand file about ten times faster than a dremmel.

[@daleburrell6273]

@@ZenithClarity ...MILLING MACHINES COME IN MANY SIZES AND MANY PRICE RANGES-!!!

[@daleburrell6273]

@@lwilton ...THAT'S THE TRUTH- BUT YOU NEED TO REMEMBER THAT THERE WERE A LOT OF WIRES THAT YOU HAD TO STAY AWAY FROM WITH THE SAW BLADE-!!! A MILLING MACHINE ALLOWS YOU TO STRICTLY LIMIT HOW DEEP YOU ARE CUTTING INTO THE CHASSIS.

[@gbowne1]

My favorite was the HRO-50T1

[@clydedenby1436]

Nice job, though I was more impressed by the presence of a milling machine in an electronics shop. I'm guessing that you have a few other areas of interest.

[@daleburrell6273]

...MILLING MACHINES COME IN MANY SIZES, AND MANY PRICE RANGES- MAYBE TERRY WAS EXTRAORDINARILY LUCKY ENOUGH FIND AN INEXPENSIVE MACHINE-(?)

[@dneitzke]

Dr. D-lab, Do you offer DVD's on all your repair you tube Vids? many thanks!

[@jimgiordano8218]

Nice heart transplant. Seeing these old rigs, brings back memories. Question, have you ever worked on a Heathkit HW-100 or HW-101.

[@daleburrell6273]

0:51...WHO TOOK IT?!!

[@generator73]

I have another oscilloscope that powers up fine but CRT screen is not illuminating ! Do you know why ? Can you give me an idea please ?

[@douro20]

I wonder how that mill compares to an actual RF-45.

[@bobl1636]

Terry It looked like there is enough height that you could of placed the transformer on standoffs that would miss the chassis

[@daleburrell6273]

YOU'RE FORGETTING THAT THE TRANSFORMER IS A VERY HEAVY COMPONENT- AND STANDOFFS MIGHT NOT BE UP TO THE JOB OF SUPPORTING SUCH A HEAVY PART. WHAT'S MORE, IT LOOKED LIKE THE LEADS ON THE TRANSFORMER WERE TOO SHORT TO REACH VERY FAR...

[@daleburrell6273]

5:35...that's called the "quill"-!

[@scole901]

so the original owner replaced the cap backwards?

[@stevec5000]

But now there is a National 240D without a transformer!

[@adrongarretson6195]

I love your videos dude you need to use a vacuum cleaner instead of sweeping that crap down inside that chassis what the heck are you thinking of

[@d-labelectronics]

Always sweep the shavings onto the mill table, then vacuum. The chassis bottom was open. No worries

[@daleburrell6273]

...I'M PRETTY SURE THAT TERRY KNOWS WHAT HE'S DOING-(!)

[@generator73]

i have a question, i have vintage vacuum tube oscilloscope and it keeps blowing fuses away, how can i fix that

[@d-labelectronics]

Hi Bob, sounds like a very leaky power supply capacitor. Have you looked over the caps? Are any leaking? Try pulling the rectifier tube, see if the scope powers then, if not the power tranny may be bad. TD

[@generator73]

@@d-labelectronics I have no idea how capacitors and rectifier tube looks like. I think I am gonna send it back to eBay and get my money back. There is no way I can fix that because I have no special tools for that. I am musician, I make music . I have no idea what leaky cap is and how to tell if it leaks or not. I am also know how to lift heavy weights at the gym but nothing about capacitors.

[@stormchsr101]

i hate theses things! the cabinet was a bear to get off and the layout was icky!. i guess its cuz im not fond of national stuff. so my repair for mine was.....i sold it

[@langhilau]

Terry is it worth the time and expense to do all this time consuming work for what could be called at best a mediocre receiver. The labor alone on your part had to be very expensive.

[@ianbutler1983]

Yeah, but then we would not be able to watch his fix it...lol.

[@daleburrell6273]

...WHEN YOU'RE RUNNING A BUSINESS: "TIME IS MONEY"- BUT WHEN IT'S A HOBBY, TIME AND MONEY ARE A HECK OF A LOT LESS IMPORTANT-!!

[@nor4277]

Cant you get a new one.

[@d-labelectronics]

Nope, those transformers were specific for the receiver back in 1950

[@nor4277]

@@d-labelectronics thanks for the info I had no idea,it's a shame you just can't buy new transformers as needed,but I understand now .