#21 Powering up unknown condition of old tube equipment safely

In this video I show how I power up old equipment safely. Tube or solid state.
You should NEVER plug something into a mains outlet if you do not know the condition of the equipment.
Specially if it is vintage.
Disclaimer: when working with live mains voltage you do so at your own risk.
Discuss:
gokarters.com/smf/index.php?to...

[@jaybats7865]

Good sound advise. Thanks Buddy everybody benefits from safety first 👌

[@hokepoke3540]

I really enjoy your videos, I have been working on electronics since the mid 1950's and I think I have forgotten a whole lot more than I remember, you reminded me I need to build a power setup like you have. I have had a variac in use for over 50 years, I am probably on my 3rd of 4th one. I am diffinatly going to add the light bulbs to mine. Thanks N5UEB

[@TheRadioShop]

Thanks Tommie for stopping in. Yes that current limiter is a must for working with older gear. Helps keep that magic smoke in.

[@IamDerick]

Thanks for the ideas. Your jig is a cool rainy day project I must build. Going to put variac on my list for the upcoming ham-fest in my area. Having fun catching up on your videos. :)

[@TheRadioShop]

Glad you are having fun with them. I am having a blast making them. Yes this is a great tool to have. A must for the radio tinkerer

[@dennisqwertyuiop]

catching up on some of your great videos thank you

[@TheRadioShop]

+DENNIS N Cool, Thanks for watching my friend

[@supyrow]

A+ i like the bypass switch idea, i might add that to mine!

[@TheRadioShop]

+su pyrow Thank you very much. The switch helps when needed.

[@PapasDino]

Happy New Year Buddy! Thanks for the overview; my left hand still unconsciously migrates to my back pocket when I approach a boat anchor - learned that lesson the hard way when I accidentally got hold of the PA plate voltage output of the Novice transmitter I was building in high school electronics shop in the late 60's! 73 - Dino KL0S

[@TheRadioShop]

+Dino Papas And a very happy New Year to You Dino. I know what you mean about putting that hand in your pocket. I really do not care for that metallic taste it leaves in your mouth lol. Thanks for stopping by my friend.

[@TRXLab]

Hi Buddy, very important point very well presented... , 73 and a Happy 2016!

[@TheRadioShop]

+TRXBench Hi Peter, Thanks for stopping by and appreciate the comment my friend. Safety is always important. Have a very happy 2016 your self :)

[@waynecarlson3736]

Great video like very much how you explain everything so well

[@TheRadioShop]

Thank you very much Wayne.

[@lazaruscome4th]

another excellent vid, good job Buddy, :)

[@TheRadioShop]

+lazaruscome4th Thank you very much Lazarus. Very pleased you enjoy them and thanks so much for the kind comments. Just want every one to be safe and make it through 2016 :)

[@Drforbin941]

Great video!

[@TheRadioShop]

+Doctor Forbin Thank you Doc.

[@Highstranger951]

Nice vid as always

[@TheRadioShop]

+Highstranger951 Thank you very much my friend.

[@Devin82m]

This video was great. Do you mind going into more detail about you variac, isolation transformer, and lightbulb setup? I understand the basic concept, but would like more detail about how it's wired, you board didn't show much.

[@TheScottgusken]

I recently had my Dads old Hallicrafters S-38 given to me from my sister. I didnt know it still existed. Im 71 yrs old and as a kid, my brother & I listened to this radio in the 60's. We listened to the Floyd Patterson & Sonny Listen fight...wow what memories, from WLS am in Chicago. This one doesnt work now. What's a total rebild cost run these days on an S-38 ? I would love to have it fixed. Thank your for any reply.. Ken.

[@sammencia7945]

Pop the chassis and look at it for 15 minutes. Visual inspection Then plug it into your iso.variac.light bulb limiter and slowly ramp up mains voltage. Test chassis for live voltage.

[@ovalwingnut]

My goodness.. either your hands are tiny (no disrespect) or that Tube Master meter is HUGE! I had no sense of scale (at first) until you pointed at it. Really took me by surprise. Also, do you have a story that goes with that Variac "knob"? If it has never been off, that is a interesting break. Otherwise, GREAT SHOW - even if I''m a bit late to the party. Cheers.

[@mikesradiorepair]

I like your idea about placing tape on the power cord until it has been safely powered up. Think I will start doing that. Thanks for that tip. For the serious restorer or repair tech a piece of equipment I highly recommend is a isolation transformer. Everything I work on goes through one. If I should accidently touch a live component I don't have to worry about getting zapped. Personally I use a B&K AC power supply that in addition to being a isolation transformer is also a leakage meter. It has a built in test probe and meter for checking for leackage on both common and hot lines. Sencore also makes a AC power supply like this. I stopped powering up tube type equipment before changing all electrolytic and filter caps. Seen to many explode over the years and just consider it cheap insurance. Honestly most solidstate equipment I work on that is over 30 years old gets all the aluminum electrolytic caps and tantalum caps changed.

[@TheRadioShop]

+MikesRadioRepair .CBRadio Agreed. An isolation transformer is a must.Mine is under the bench and there is a AC outlet on the bench that my variac plugs into. So many times I forget that it is there. Should had mentioned that in the video. Thanks for the reminder. I have always used that tape method for years. Just a little insurance for myself. Getting to old to become a conductor.Thanks for your reply and comment bro.

[@mikesradiorepair]

+The Radio Shop LOL, to old to become a conductor. Is there a age it's ever good to be a conductor. :) I learned when I was a kid all about being a conductor. They make the wire coming out of a TV flyback transformer bright red for a reason. I don't know what hurts worse, the zap from the flyback transformer or your hand getting impaled on something when you involuntarily yank it out the back of the chassis after being zapped.

[@TheRadioShop]

+MikesRadioRepair .CBRadio He He, that is what we call a double zap bro :)Speaking of conductors I would only want to be one if there is a train involved :)73

[@mikesradiorepair]

+The Radio Shop Or a orchestra :)

[@dougroundup7315]

its the involuntary reaction that gets you everytime! Did the same thing as a kid just as I was thinking I knew enough I got complacent and ouch not only shocked but hit my elbow right on the funny bone and hit my face with open hand got bloody nose. My mickey mouse wind up watch was permanently magnetized too.

[@freespuddy]

I've got the same variac as you, and it has broken pieces off the knob like yours. Tried several kinds of glue that didn't last long. Finally settled on a good amount of hot glue, and that took care of the problem.

[@TheRadioShop]

Mine was missing the piece of the knob when I got it. Need to find me a replacement. Good old variac. Thanks.

[@freespuddy]

It is a good variac. I've used mine for perhaps 40 years with no problem except pieces of the knob breaking off.

[@atoiler1389]

It’s almost like those Variac units had knobs made of Bakelite.

[@Sodbusterrod]

A question on wiring schematic at 5:05. Other presenters wire the bulbs in parallel to get more current draw and increased safety. Your thoughts?

[@stationvictormike3415]

I see different variacs on eBay. Trying to find one that will do fine.

[@Okie-Tom]

Nice safety video. On your board, what fuse do you have? Thanks

[@TheRadioShop]

Thanks. I use a 1.5 amp.

[@jameswilson197]

I have and use an old Swan 350 HF which I have refurbished. Lots of high voltage in those output circuits. KE7HTU

[@lomgshorts3]

Your power supply needs an isolation transformer. It is not safe enough to rely on the variac as isolation. Then you could work on the AC/DC radios that do not have transformers. It how I built mine.

[@TheRadioShop]

You are right. This unit plugs into an isolation transformer.

[@daleaferrrier]

You mentioned how hard it would be to get replacement transformers on these old pieces of equipment. Have you ever tried to re-wind a new transformer based on an old one? Would it be that hard other than a lot of labor of course...

[@TheRadioShop]

I have rewound several types of transformers. From small to big. Very labor intense I may add. It can be dome.

[@derrickbaranowsky5715]

Assuming there are two bulbs here to increase the current capability of your limiter protection device, why are the bulbs wired in series instead of parallel? Wouldn't you want to wire the two bulbs in parallel to increase current protection capability rather than series?

[@atoiler1389]

Would be nice to read a response to Derrick’s enquiry! I also had same though…

[@galaxyflyer1]

Hi Buddy, I was wondering why you use two 100w bulbs?Thanks for all your videos!

[@TheRadioShop]

More desire than anything. I do have a switch to remove one from circuit. I can install 2 50 watt bulbs instead of using 2 100 watt. Thanks for asking

[@earnieb5318]

Buddy, you have a 3 wire plug but your schematic only shows 2 of the 3 being wired?

[@peterjones3245]

I notice there was no earth connection to the equipment under test. I think you can use this circuit with the addition of an isolating transformer so that the supply to the equipment is "floating" so touchingh earth and a feed line will not result in a shock.

[@jamesharrison2041]

''HELL'''' THERE ARE NO LIMITS HERE''''' WE ARE TRYING TO ACCOMPLISS SOMTHING''''

[@waynecarlson3736]

Would you consider installing a voltage meter to know what the applied voltage in fact is??

[@TheRadioShop]

Yes, I always monitor both sides of the system when powering up rigs. I use two volt meters.

[@sharonlee4773]

Hi there,Did you ever live in UK? I can detect the odd word.

[@glennkeiser8202]

Just remember that ALL electronic equipment comes from the factory with a lifetime of smoke included. When the smoke LEAKS out, it’s broke!😵‍💫

[@jma8352]

in the diagram how dose the light bulbs get the neutral? i just see hot wire

[@TheRadioShop]

If you go back and look at 5:20 in the video you will see the schematic of this. The neutral is carried straight through the system. The lamp only gets a neutral if there is a short in the unit under test.

[@jma8352]

@@TheRadioShop got it thanks, just the black wire interupted by the light bulb thanks!! i have a 1 to 1 isolated transformer pluged into variak pluged into gfci circuit

[@BruceNitroxpro]

Wondering if you use an isolation transformer now?

[@TheRadioShop]

Yes, And is mentioned in many videos.

[@BruceNitroxpro]

@@TheRadioShop , Just watching out for you! Can't have you accidentally sliding off screen because of no isolation transformer! LOL 73, Bruce

[@SignalViewRadios]

mickey mouse likes warm places lol

[@TheRadioShop]

Yes he does.

[@carlrudd1858]

Why two bulbs? Most have only one.

[@ovalwingnut]

"I'm" guessing adjust-ability? It would be pretty easy to spin one in our out for one's wattage needs? On a side note, I've tried to find any other (cost effective) solution to incandescent bulbs.. nada :O\ Pretty COoL for a tiny wire in a vacuum :) Cheers CR