Pimp My Cheap Variac with LCD Voltmeter Ammeter Display 

The laugh i had when you turned on the power and the display was upside down lol

thx so much for making this video Brad! lovin the channel, been tuning in for a few years now! cheers.

Love your channel man. I've probably seen everyone of your videos haha. Just opened up a shop in January and you were one of the reasons I finally decided to bite the bullet and do it. Just picked up a new Variac today and decided to do your mod. Works like a charm!

Thank you for this video. I didn't want to modify my older variac but went ahead and got one off Amazon with the LCD display and did the mod today. Pretty straight forward after seeing your video. Keep up the great work!!

That was the exact variac I was looking at and I to wanted to put at least an ammeter on it, this is just what the Dr. ordered! You are the man Brad! Thankz

You can make a fifth wire running from the hot side of the fuse to big yellow capacitor inside the digital meter by cutting the bottom lead from the board and heat shrinking it to the new wire. This will let your digital meter start reading from 0 volts instead of starting at 65 volts. Saw this hack on another video.

Great idea Brad. eliminates meters all over the place. Frees them up to do the actual tracing and testing. Might just have to grab one of those for my variac. Thanks pal.

Oh Brad, brilliant. My variac has no meter whatsoever. I've got 2 old Bakelite meters, an Avominor I'll be using for Voltage and a moving vane 90A Hublot that I'll be completely rebuilding as an ameter but I was thinking I want a display like Brad's so I looked on Google and found this at the top. Wow, I was so pleased to find it was you, I didn't go looking for your video but it makes my day to find your guiding hand.

I followed your instructions perfectly. My meter was upside down too till I watched the rest of the video.

Brad, old buddy, I took your advice and searched the web and found both items. The 5 amp variac I ordered from Circuit Specialist in Tempi, Az. It was $54.99/free shipping. The ammeter I ordered from Amazon (prime-free shipping)for $11.99 NCElec brand. I am set to install filter and bypass caps now and bring up to voltage slow to form them! Thank you for the info and encouragement. Thankz

Sweet Brad. You were the first video to pop up when I searched for the mod haha

I did the same thing to my variac. Mine has is a smaller Volt meter. I replaced the small analog with a digital. It gets the job done and it's a lot easier to use!

I have been watching you videos for a while and enjoy them very much. I am a guitar player and a technician as well. I have a few questions: 1. Where can I get the best contact cleaner for cleaning pots, switches, etc? 2. I need a schematic for a Fender Deluxe Reverb amp, as well as a power transformer, choke coil for it. Where is the best place to get these items?

so looking at the diagram on the back it looks like your mains hot and neutral should be on the 2 center pins. the out put from the trans former should go to the load which should do all the sensing for voltage and current. that is probably why it doesn't come on until the variac reaches 65VAC.

Thanks Brad! I just did this and it works great!

just did this mod to my Ebay/Amazon Variac! works great!!!

Hi Brad, I wanted to ask you a question about a variac that I bought from a company in British Columbia in Canada. I have the red variac that is rated at 5 amps @500 watts 0 to 130. I have a vintage Fender Blackface Bandmaster that I wanted to lower the voltage to play this amp with this variac. Are these variable transformers just basically to dial your voltage down to 110 volts and you're good to go? Do these variacs need any special grounding done to them to use them for playing the amp other than rebiasing the amp ?Thanks Michael Newell from Niagara Falls, Ontario, Canada

Here's some tips for dummies like me that can screw up even the simplest of circuits. - Take a picture of the Variac's wiring when you first open it up for reference in case you get confused and want to start from scratch. - Although my Variac looked identical to Brad's on the outside the wire colors were completely different. Also, mine had the fuse wired before the switch (which I believe is probably preferable). - The wall plug hot goes into the right side of the Variac's copper coil winding. The wire that comes out of the left side copper winding is bonded to the wall plug neutral . The sweeper is the HOT. This is probably obvious to most viewers of this channel but it was surprisingly difficult to confirm this on the net. - My meter had a different way of wiring it. It was a Drok brand. Sweeper wire AND the wire that goes into the face plate receptacle HOT both go into pin 4. Variac coil / neutral / blue wire into pin 3. Neutral face plate receptacle wire into pin 1. NOTHING into pin 2. - Finally, if you hear a decently loud buzz when turning on the Variac or when dialing it up a bit - ya done sumthin' wrong! Ask me how I know... Hope that helps someone out there. Everything above seems to check & measure out proper for the meter I got. If I still don't have it right please correct the info. Thanks Brad for all you do!

Hi Brad good to see your into this also. Is it true the range of the lcd is really starting at 80Vac? For a Variac use you want to go, and see visual below that right? Visual range like 0-500Vac is a must, so Why technical made them like starting at around 80Vac Cheers mate ✌🏼

You REALLY need a Sencore PR570. Worth every penny. It has an extra isolation transformer for working on hot chassis and you can set the trip level to save fuses. Carry on. Love the videos. Robert

amigo gracias por tu aporte! buenas noches! tienes el diagrama donde se muestra la modificación?

Hey Brad, small suggestion, how about a small re-wire? Feed the meter supply - outer terminals - direct from the incoming mains supply & post the power switch. Keep the power socket across the inner two terminals obviously. This way you don't have to wait for the meter to start up at the voltage dictated by the Variac? & I promise I didn't laugh when, upon application of volts, the display appeared upside down. Thank you for this & all your restoration videos - happy new year mate:)

I've got an old GenRad 10Amper. Wouldn't it be cool to install one of these right into the front, 'cept they're built like a tank.

Quick question Brad. Did you remove the ground wire on your variac or is that the way yours came? I see the power cord for the variac has the ground still connected but my variac has another ground going from the ground plug to the variac itself.

Do you use an isolation transformer in addition to the variac? As far as I can tell, the variac you use (which is pretty much the same as mine) doesn't provide ground isolation. I'm wondering how important it is to have ground isolation.

Is there any difference in variacs expensive vs cheapo aliexpress?

Brad, awesome videos on this. I just got a similar variac with a similar meter. It works great except for one thing. The numbers on the meter don't seem to be changing real-time, meaning as I turn the variac up and down, the numbers on the meter only change every second or so, not instantly like yours does in the video. It could jump 10-30 volts depending on how fast i'm turning it. Any idea why it would be doing this? I've checked the wiring and tried different schemes. I've also tried a second meter and it does the same thing. Would the gauge of wire I used or anything else about it cause that, or could it just be the difference the way my meter was made? I love having this mod but it's driving me crazy that it doesn't update quicker. Thanks!

Brad, found you here for the meter. Thanks for the direction. Put the meter on my Christmas list. I noticed you said it starts reading at around 60V. Is there any benefit to somehow getting it to read from 0 V on up? Thanks, Mark

Since the making of your video, two modifications to these autotransformer meter installations have become popular... One, the voltage supply for the meter itself can be separated from the DUT. This will allow the meter to read down below the minimum required voltage limit all the way to 1 volt. All that is required is lifting the leg to a particular resistor and adding a wire to that leg. Two, the minimum current reading can be reduced by adding an extra set of windings to the current coil, via a selector switch. One side of the switch has the DUT wire passing through the coil just once. The second side of the switch has ten windings through the coil. So, for instance, the meter's 20mA minimum current reading ability can be reduced to 2mA, by doing a little math... That is, divide the meter reading by 10. Both modifications can be found in RU-vid videos. IIRC, The HWCave has instructions for both... One of the mods for sure.

The meters manual says the working voltage starts at 80VAC, so if you're getting a reading at 65VAC, you're doing well. I wonder if there's a digital meter panel that will have a working voltage lower?

I hope you read this comment and reply, If you connect a 110 Volt, 100W incandescent bulb to your variac, what will the meter show for the wattage? I have the same meter and mine shows 14.2 Watt,(@110 Volt) I fully expected it to read 100W, why do you think it does not show the actual wattage? is it because how the meter is formated? thanks, Ken.

Have variac prices come way down? Under $60 for one with digital already.

Here are links to the variac and LCD display used in this video: 500V 5A Variac - amzn.to/2qGFCXe Digital LCD Voltmeter Ammeter: amzn.to/3RLrB9R

Can I use the PZEM 61 instead of the PZEM 21?

Do you have an isolation transformer too?

Hey Brad, how long to leave the voltage at the lower amounts? Start at 0 and go up to 30-40 volts for 5 mins. Then 70-80 volts for 5 mins. And then take it up 120. Is that right? Or should I wait longer in between the increases of voltage? Thankz

Yeah I did the same thing with a different panel meter. I have never found a panel meter that goes from 0 to 130. A little irritating if you need a lower starting voltage for re-forming caps etc..

I'm curious abut how accurate the current reading would be for rectifier circuits (like amps). The current draw is on the voltage peaks, not continuous, so you may need a "true RMS" meter to get an accurate reading. However, this is probably good enough for troubleshooting. Too bad there isn't a way to power the display separately from the voltage being measured.

I just got a Variac like this same one. I found the voltage is WELL above the rated 0-130 volts. Though my digital multi-meter at full power its showing 236 V, and its at 120V around the 70 v mark. REALLY not accurate dial.

Is it isolated from ground?

wondering if you had done the 0v mod on your variac meter, or if you would reccomend the mod, thanks in advance.

How can make rectifier 12v. 100 amps with veriac switch ameter and volt metre

I'm confused. At 1.15 of the video the unaltered variac shows a red wire from the variac to the case internals, and at 1.56 you show a red wire to the completed ammeter, but at 2.39 there is no red in your completed alteration to the case internals??

Great Video Brad...... I've been itching to pull the trigger & buy one of those Variac's Now I will for sure \m/

That's really clever!

Hi Brad, I was talking to you before, but I failed to see this video. I just recently bought this exact variac for $158.00 USD. God, I got ripped on this deal. The question that I have is one concern. I saw this guy on RU-vid that was saying and showing how he had to solder another wire from the ground plug to the chassis. Is doing this necessary for playing guitar amps through this? Is there a problem with getting electrocuted? It seems to me if this were the case ,then how could they sell this, if it's dangerous to lose. I see on yours that you don't seem to have done that. Please let me know. And just one other thing, are all of these meters on these variacs off? Thanks Michael Newell from Niagara Falls, Ontario

Hey bud, if I can get a Staco 3PN1010 variac that works on 120v out & supposedly not on 140v out for $63 delivered, should I risk it?

Hi!!, it´s possible to use a dimmer like a variac using the same display?

What a great idea!

hey Brad, I tried this mod and it didn't work for me. I have the same meter and the same variac , however I have noticed my variac has 4 wires coming out of it instead of the 3 yours appears to have. the extra wire hooks to one of the plug lugs on the output plug and goes up and inside the top of the variac. I wired the rest of it up like you did but the voltages are way off. it's starts out at 150v and as I turn up the dial the voltage on the meter drops down then around the middle of the dial it starts going up again. now with my multimeter hooked into the output plug the voltage starts normal and climbs up as normal. but then the voltage on the multimeter was going way higher than this thing is rated for, like over 220v. I'm not sure what I did wrong

something else to consider (safer & no mods)... 1) plug a plug strip into the variac output, 2) plug an AC volt meter (to monitor variac'd voltage) and the amp into the plug strip. good to go.

watched... enjoyed

There's a video wherein the guy shows that the ground wire wasn't making a solid connection due to the powder coating on the variac.

Good idea... glad it worked out. Now seeing that your idea works, I'd want mine to read ok below 65v.... That's what we all do though... see someone else's project and think of how we can make it "my style"

I hope you get a kickback from Amazon and whoever makes hot glue sticks for this video. I'll be ordering everything tonight...( sans the glue sticks). LOL! Thanks Brad for another great vid.

"rectify that"....I see what you did there :)

Hook power to meter up to power switch of variac not to output of variac and display will light up instantly. If you can't measure current until you've applied 65VAC you may have already smoked your amp.

Nice!

I couldn't follow your direction on wiring the meter, I'm just a hobbyist and need a step by step on every wire to solder, luckily I found another video that explains the wiring very well, this is a good video but not so great if one want to learn how to connect the meter.

$2000 variacs showing up on the ads for this video. Jeezless H. Christy

Yikes! Looks like the metal case on that Variac is not grounded. If any one of several wires breaks and touches the case, the case will be (electrically) hot.

sweet

Amazon has done it again! The price jumped to $109 for that variac.! Not your fault. It happens a lot! Might be a bargain or two still out there, probably have to pay shipping! Bummer, I was just getting ready to order one, too. Thank you anyway, you tried! Thankz

I need to replace the meter on my variac. Glass cracked

I thought this might be handy Brad m.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wPFaEFEembc.html This person modded their meter for a constant supply voltage input. It's important to note their discovery of bridged terminals so this needs to be considered when wiring it when modded. This allows the meter to maintain circuitry power down to 0 volts while still using the variac output as metering and current reference. I tried it with a similar but differently laid out meter and it worked like a charm.

"Chime" was advertised on this video

You said "load."

I have one of those HFT Kill-a-watt P4400-01 digital meters that plug into a variac, give voltage, amps, and wattage use. #93519 28$

Thanks for this video! Just finished wiring mine up. I took a Dremel to the faceplate and mounted the LCD into the variac chassis. I move the switch and other components around, and it basically looks like it was designed to have the meter built in. I also found this other tutorial (linked below) from someone else who saw your mod and made some adjustments so that the voltmeter can read down to zero without losing power. Also, for anyone else trying this, note that you'll be disconnecting the existing lead between neutral on the socket and neutral on the switch. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wPFaEFEembc.html

For a video on how to make the meter work from 0-full output look at this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wPFaEFEembc.html

The variacs are sold out already...

This guy is pimping his Variac. I don't even fucking HAVE one, I just use a god damn dimmer switch to brown out my peavey classic 30.

we are the manufacturer of variac, all type

a nice "cheap" project...

totally useless if the meter only starts at 65Volts.