How to Repair dead National NC-270 Tube Ham Radio Receiver Weak power supply no signals 

Very Professional and competent

35 years. WOW. I look at that and think of the hours I would spend at night turning those dials. Thanks for the Ham Radio video. As a guitarist I love your guitar amp videos but these ham radio videos have a special place with me. They remind me of my Father and I sitting with his JVC at night tuning the dial to hear what's going on the shortwave bands. THANKS!

very good repair skills and perennation style 73

Hi Terry. Always practical advice in 30 min or less. Excellent! “Dead nuts quiet....”. Priceless.

Good stuff. I run into tubes in the wrong place or wrong type all the time...But I have never seen a wrong Cap Can before. You would think that someone who knows to replace a filter cap would know BETTER than to put a lower voltage cap in. The Radio Gods smile down on you every time you bring Golden Oldies back from the dead. Bless you Terry.

Nice work, Terry! I love watching you bring antique gear back to life. There's something magical about it all, especially when you fire it up in the end and I hear the broadcasts. My grandfather was a HAM down in Florida. Last we visited I was all of 5 years old (55 now) and I would sit and listen to all he was doing. I guess that memory and feeling has stuck because it resurfaces through these kinds of videos you do. Merry Christmas and Happy New Year, Sir.

I know the feeling about not having time to do these projects. I stopped taking in work because the day job just takes too much time away. Maybe I’ll take in a few things next year during my 5 weeks of vacation.

The pure magic of radio 😊👍 73 G0HFL

Terry - Great job resurrecting the old National NC-270! 73 Paul AA1SU

What a beautiful piece of equipment. It's nice to see vintage gear. Thanks for the video.

Good looking old radio. Nice big dial that makes operating a pleasure.

That is a very nice receiver. I use a small ultrasonic bath for cleaning knobs, saves hours with a toothbrush. Always jealous of American Ham gear, really beautiful stuff. Happy Christmas everyone.

Thanks Terry, good to see the older sets up and running.👍🇬🇧❤️

Great job, Terry, as always!

Really impressed to hear Jacksonville, Florida all the way up there! I actually looked up that call sign and was surprised to see how available information actually is! For the record, I'm also in the Jacksonville region. Looks like I really ought to get into HAM.

I have an NC270 receiver that works perfectly and I bought it off ebay last year. I just replaced a couple old filter caps and that was it works great. They are really easy to work on compared to other radios I have worked ion. Thanks for sharing.

Radio sounds beautiful! Nice work!

Awesome repair! I learn a lot from your training videos!

Well done as usual Terry !!!!!!

Another receiver saved and thanks to the magic at D-Lab! Merry Christmas Terry and have a safe New Year! Steve

Thanks, Terry, always an enjoyable viewing. These vintage rigs are always so interesting, to see how the styling changes over the years. For some reason when I saw the National logo I immediately thought of the Gonset one, even though I'm not sure if I even remember what it looks like!

Im reliving a 55 year old memory LOL. That had a flip down front panel I think. Thanks for the memory.

Love watching radio repair videos!

So cool ! Merry Christmas ☃️🎄 and Happy New Year!

I liked it when it made that sudden pop and hiss sound and you said "scared the D lab", as third person narrative.

Nice looking and sounding radio.

Love the old TUBE gear

Often hear K2TRD here in Ireland, He really puts out a nice signal.

Merry Christmas D-Lab

A very beautiful receiver

love your channel

I very much like to see your videos. Good information and a really pleasant way of presenting. Alan, WA2EGA

"There is audio but no intelligence on the audio" sounds like my in laws.

This is my passion as well, I am working on an old RF Amplifier that has not transformer in it. I thas doubler circuits to bring the 30KD6 tubes up to 160 volt and also down to 12 volts to run the relays circuits for the preamp as well. I will replace all the electrolytics, some burned up resistors and check all the keying and amplifier transistors to make sure that all voltages stay where they need to remain for use. I also have to re-wrap a 40.1 uH choke for the High Voltage PI network for the Load and Tune circuits. I have determined that this amp has been keyed too long and it heated up past the its ability to cool itself without a fan in operation of this device. I will install a fan in the tube section to try and keep this problem from ever happening again. Bought the amp for 50+21 for shipping, the switches seem to be ok but will do a check on them as well before placing in service for the new owner, whoever that might be. This should conclude the rebuilding of this fine old RF Amplifier, that should put out about 100-150 watts of continuous Rf power. This should work nice for a driver as well while running on low side for a low drive amplifier. All without schematics.

Happy New Year Terry

Beautiful National NC-270! By the way, there is a guy on the Facebook E.F. Johnson Collectors group. He said he is looking for a Civil Defense Viking for the CD Museum. I told him if there was one anywhere in the U.S. you would probably know where. Anyways..., excellent work as usual! John

Really love the Ham related videos Terry, you need to retire so you entertain me more often😀.

Very cool radio

Watched further and see you use deoxit liquid will try and locate it here in nz before trying overseas thanks mark

Great job

I have been surprised in these kinds of stories about one of my favorite approaches missing. That is checking the power filtering components with a volt/ohm meter. Before I got my present collection of measuring instruments, I had to do most of my trouble shooting with applying a bit basic math with voltage and resistance measurements. Realizing that most of the filtering was implemented as series resistors and parallel capacitors, I checked the resistors. Then I applied power (gradually) and measured the DC voltage drops over the series resistors. That gave me material to calculate the current(s). After that I measured the AC ripple voltage at the capacitor terminals. That allowed me to calculate, or at least estimate the value of the capacitor. It is not terribly accurate when the meter measures an average of the presumably sawtooth Ripple. With an oscilloscope I can measure the peak to peak voltage for more precise results, but that is much later capability. Similarly, nowadays there are low cost capacitance or RLC meters. What I was trying to tell was the ways I analyzed the power filtering stages in the old days. Ohm's law for finding the current and for the capacitance any variation of the formula Vpp = (I * t)/C, where t is near 6 milliseconds on full wave rectified 60 Hz or near 8 milliseconds on 50 Hz. The peak to peak voltage is somewhere around two to three times what the average reading voltmeter indicates. Also, if there are more resistors, you can calculate the capacitor leakage current from the difference of the supply side and load side DC currents. "It's basic, my dear Watson", or something like that, as I believe Sherlock Holmes was saying.

Sounds great.

Good job

love the ham Stuff Thanks Terry... Vic KE8JWE

At least that one is full of ceramic and film (dip) caps.... that usually means less bench time.

Nice radio my realistic 160 is all slug tune d

Very cool.

Would love to see you working on a home brew cloud warmer.

excellent

nice work 73 de HB9GNK and KB9GNK

Actually that thing is beautiful! Is that a popular model? I think the look of that is very nice.

My nc-270 is needing this...thanks..WA5MKU

Terry, love your videos! I’m learning so much! Quick question: if one was looking to jump Into Ham radio, what should they get as a basic setup. I’d prefer vintage tube stuff, if possible.

TLC was all that was needed.... up she comes in all of classical glory!

Why does the Deoxit 100 solution is better to use on switches compared to the Deoxit switch cleaner? sometimes switch cleaners and solutions makes the switch contact worse causing more problems

Any thought to putting a begin on the new 136 KHz Feq?

Thanks and I vote for more ham radio related videos also. One question....how did you clean the knobs?

Great work Terry. I have a Browning R27 S23 set. Has no receive. Have new tube set. Would you be willing to have a look? Thanks! John, Jackson. ")

Terry; don't you have a sig gen capable of doing a receiver alignment? Do not think I've ever seen you an alignment - come to think of it . . .

I have Eddystone Ec10A/2 it working only last 4 months now it completely dead parts are not available in country and professional Radio Technician is also not available.

Hi Terry was that a can of Craig's deoxit on your desk .can you still buy it? Thanks mark from nz

As usual, a very good video. Especially for newbies. Things like why you moved the cathode resistor and the associated electrolytic capacitor. I had hoped you were going to go into a bit more depth, things like how to clean the knobs, cleaning the chassis, etc. But still a very fine video. I was watching another guy's video on a radio repair, and he used something I have never heard of to clean the chassis. It is called "Mother's Mag and Aluminum Polish" and if you want to see how it did, the video is at ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-i8ZbVIVoKLY.html I was amazed by how well it did on the chassis. I am not sure it would have done any good if there had been a lot of rust on the chassis, but still, it is interesting to see how well it did work on this radio. This particular video is "Part 3" of a series, you would need to go to his site to find the first one to start from there. I provided the link because I thought you might be interested in the product. Keep up the excellent work! 73, WB4RHA

Sounds a bit like xrayonyb there.

is this National Panasonic?

HNY Terry, 73 de HB9DQP

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