I Don't Know What I Bought, But I'm Going To Fix It.

[@neilh2669]

Thanks Ron, that brought back a memory. Long before I was around, my dad built a Heathkit VTVM. It had a face much like yours, but the rest of the case was Masonite. In the late 70’s my Atari 2600 failed. Dad used the meter and correctly diagnosed the problem. The power wire broke where it entered the wall wart. His repair looked perfect but he forgot to maintain polarity on the wires. He wanted to trace the wires with an ohms check, but couldn’t zero the meter with the knob on the face. I had smaller hands, so he had me turn an internal pot with my hands wedged against a tube. The adjustment was slowly working im until I gave the pot a big spin. One of the tubes shorted - very exciting. The meter was “broke.” The local TV parts house wanted $30-50 for the tube. He refused to pay that and threw the meter away. (Wish he would have let me keep it.) I got a new Micronta for about $15.

[@AmateurRepairTime]

That’s great what a story! The tubes are really cheap now ironically

[@neilh2669]

To be honest, the tubes may have been much cheaper elsewhere, but we were in a small town and I think they were the only supply left in town, so that was their price that day.

[@KentDiego]

A VTVM has a very high inpu impedance so it does not load down the circuits you are trying to measure. Useful for radio circuits.

[@InsideOfMyOwnMind]

As the owner of an RCA Volt Ohmist VTVM I have not screamed at the tv this much in a long while. In your defense no swear words were used. It was fun watching the discovery process.

[@InvestigationsDepartment]

I understand your reactions and experience the same 😂. If he was just a bit older there wouldn't have been any mystery!

[@myradiovideos]

Raining in San Diego, AGAIN!!!! 😞 So good time to watch the video,,, Love those Antique vintage shops, we once had about 50 in the San Diego area, but most have closed up for direct sales to eBay.. I think we now have only 3 left, and those are not very good!! OK lets see how you do on the What looks like a Heathkit VTVM Meter,,, I own 4 VTVM... All very high end units,, To bad for $5.00 you did not get a HP 410B VTVM,,, now that would be a STEAL!!!! 🙂 VTVM is needed to read the Grid Voltage on tube radios.. A new Digital meter will Load Down the voltage and give you a False Reading,, so a VTVM is a must have.... Robert

[@AmateurRepairTime]

Ahhh that makes sense I’ll look into that

[@ronaldkrisher3685]

Loving the vids. I'd like to add to the comment from @myradiovideos. As you know, an ideal voltmeter would draw no current from the device under test. It would have infinite impedance. Back in the 70s, when I was a strapping young lad like yourself, a typical portable multimeter had no active circuitry. They were meters with resistor voltage dividers and that's it. Typically they had an input impedance of 20k ohms per volt. So on the 10V scale the input impedance would be 200K. On the 50V scale it would be 1 Meg. These meters have the ohms/volt inscribed on the meter face. Maybe you've seen them. Your meter has an input impedance of 11 Meg, so way better for high impedance electronics like vacuum tube circuits. Most modern multimeters have active circuitry with impedance of 1 Meg or more, so better than the 20K / Volt days, but maybe not as good as your VTVM. It's good to know the impedance of your meter. Does that mean there is no place for low imedance meters? Actually no. Low impedance meters are good for power measurements in your house. When wires run near each other they form capacitors. A disconnected circuit can be energized by capacitive coupling with an energized circuit. This capacitance makes a voltage divider with the meter impedance. So a high Z meter can indicate a voltage on a de-activated wire. They call this a ghost voltage. It's real enough but it can't hurt you. A low Z meter will dissipate this and accurately indicate whether the wire is energized. Some new meters have a Low Z feature so you can select the appropriate impedance for the job. Kind of a long comment. Keep up the good work.

[@AmateurRepairTime]

I didn’t even know the impedance matters but that makes sense!

[@ronaldkrisher3685]

Here's some possible grist for your video mill. If you have a relatively low impedance meter (say < 50K/volt) you could compare and contrast. Use your Heathkit to measure a switched wall outlet. With the outlet off you will probably see a few volts of ghost voltage. The Low z meter will drop to 0 V. Then measure a tube grid bias in a radio or amp. You will get different readings from the two meters. The low z meter might even affect the circuit operation. The circuit sees the meter as a resistor.

[@sguttag]

I have a later descendant of that one (and the bench version). It is still one of my favorite meters (IM-5228). They didn't change a whole lot through the versions...mostly color (later ones were white and blue). One update they did was on the later versions is they put the calibration pots behind some holes in the faceplate so you could adjust them without taking the cover off (but you needed a small screwdriver to get through the holes). There are a lot of times when analog meters are preferred to digital...particularly when adjusting things. You probably won't want to use it for reading resistance since you have to calibrate it each time you change scale (Inf. and 0) but it will get to higher resistances than typical DMMs. With alkalines batteries, I store mine with the battery out. That old carbon battery won't leak like the alkalines. I don't think Eveready makes their Ultimate Lithium Ion batteries in "C" size (they do make AA and AAA sizes). Those won't leak and have a 20-year shelf life (could be used on your pinball machines instead of putting a coin battery or NVRAM).

[@augurkur]

I had one of those for years. Super handy on radio circuits where you need tens of millions of ohms impedance on the meter circuit.

[@AmateurRepairTime]

I didn’t even realize I needed it!

[@augurkur]

@@AmateurRepairTime A good Simpson is probably close enough at a million ohms for most stuff. If you've got things going wrong in the interstages between transformers you might want more impedance to avoid deafening the receiver while trying to fix it. For example when tuning a slug.

[@augurkur]

The resistors are probably wire wound. My friends mom worked for a military contractor in the 80s making these type at home by hand. She simply measured the value to make sure it was exactly right before tossing it in the bucket.

[@andrewblack4100]

Great video, Ron. You did very well paying $5 for this quality VTVM, but others may not have thought to troubleshoot the joints as you did. This will come in very handy when you are aligning the many radios you have on your shelves. I have a similar meter (a Jackson) and I use it regularly for this purpose.

[@AmateurRepairTime]

Thank you Andrew

[@Dutch-linux]

A VTVM is a high impedance voltmeter that wont pull a load on circuits and they are mostly used to adjust bias and other sensitive adjustment in audio gear and tv if circuits

[@timmooney7528]

My uncle gave me his old one. The model I had looked the same except it had the blue-green Heathkit color scheme.

[@AmateurRepairTime]

Thank you Tim

[@KB1UIF]

It is a high impedence multimeter. Uses vacuume tubes inside. The ranges are independent voltage ranges and resistance ranges. Those are precision resistors around the rotary switch. You can download the schematic diagram for it. The filter cap is likely no good. I think the little black cube could be the rectifier. The adjustments correct for the tubes for accuracy. It is accurate when it's calibrated. If I remember right, the battery is for a bias voltage, it uses very little current so the battery might still work. When you use the meter or calibrate it it should be stood upright. If you lay it down you will get an error.

[@frankgagliano9677]

Great video Ronnie, I hope you get a chance to use it in the shop. I hope you never run out of space for your great finds. Great job in making the old machines run like new again. See you on the next video.

[@AmateurRepairTime]

Thank you Frank, are you taking care of Elvira for us :) ?

[@frankgagliano9677]

@@AmateurRepairTime played her a few times, the ramps look great. Can not wait to see the video. I know it was tuff.

[@hestheMaster]

Five bucks! You did good Ronnie. Since it needs a "C" cell battery to measure resistance you may want to check out a device you can build or buy ( I went that route) called a battery eliminator. It works great on my VTVM. Never will need to replace the battery now.

[@AmateurRepairTime]

I’ve heard of those I suppose it’s a little circuit that runs off the transformer?

[@eDoc2020]

@@AmateurRepairTime There's a common circuit which works great with these standard VTVMs. I think it's three silicon diodes, one capacitor, and one resistor.

[@InvestigationsDepartment]

It is one of the most accurate things you could use as test equipment for it's time. High impedance. You probably don't see anything like the conventional diodes in there. You would be fully aware of all it's functions if you were born say in the 1950's. I'm glad you are able to figure stuff like this out so nobody has to explain it all to you. See Mr Carlson's lab on youtube for his restoration of vacuum tube meters.

[@JamesUK-je4ew]

Love the analog meters and this channel. Thanks for sharing. Regards

[@AmateurRepairTime]

Thank you for watching James!

[@zaptainkuboom5520]

Nice peice of equipment. PP is reading peak to peak of the sine wave. You need to zero the meter pointer, while the meter is turned off by turning the screw at the bottom of the meter movement

[@AmateurRepairTime]

I did that in the part you skipped

[@zaptainkuboom5520]

I was watching the video while commenting.

[@werner.x]

I'd expect this calibration to be off unless you prove otherwise, since you usually cannot calibrate a mechanical meter laying sideways. Should be used in the one or two working positions it is built for. I assume, the Heath meter do have just the upright (perpendicular) working position, since they don't have the sign on it for horizontal use.

[@AmateurRepairTime]

It won’t sit upright with the back off and can’t be calibrated with the back on. I guess I’ll throw it away

[@werner.x]

@@AmateurRepairTime I'll clamp mine down for calibration, if this is the case. Just tried - sitting sideways moves the needle. Usually there's an inverted T on the scale, showing two possible meter working positions. But most bench meters won't even have this sign. Makes kind of sense, no horizontal use for a boatanchor bench meter anyhow.

[@werner.x]

@@AmateurRepairTime I'd say, throw it in my direction, please 😁- but i'm too far away. Won't work ;)

[@jameskenney5623]

I love the fact that you still find the time to interact with the trolls. Amazing video as always

[@jameskenney5623]

I've got to be honest I didn't think this video was going to be interesting to me and even though I have no clue what that machine does, you made the video interesting. Testing the battery and your reaction was classic and the fact that you went to the store looking for Glim was AWESOME!

[@OhRonaldo]

Dat's why theres a zeroing knobby thingy, to adjust for the tube thingies

[@jonka1]

Nice meter and so accurate after so many years. I would replace that 150 volt electrolytic it's going to fail at the higher voltage. Don't leave it.

[@TubeRadioRepairRestoration]

Those are not the original tubes. Good job on the function switches and reading the meter! Those resistors in cardboard tubes are 1% precision resistors. My understanding is the d- dc+ is just so you dont have to switch your leads when the meter swings the wrong way. I'm scratchy on my vtvm circuit memory but I think the 6al5 is a full wave rectifier and the 12au6 is part of the bridge circuit and has 2 sections that needs to have equal readings in order for you to make accurate measurements.... with 5% accuracy that is. The battery is just for ohms readings

[@douglashoff95]

Better to have one of these than some of the digital multimeters of today. There are many things these can do much better. I'd say you got a real bargain. Was $24.95 in the 1956 Heathkit catalog.

[@Recoils-electronics-repairs]

Have a few vtvm on my work bench handy bits of kit for certain jobs on radios etc wish i could find stuff like that in the uk at that sort of price paid £40/60 each for mine

[@AmateurRepairTime]

This one was on clearance 😀

[@werner.x]

@@AmateurRepairTime For a meter with probes and in this condition it really was a steal. I recently paid 30,-€ plus shipping for a IM 11 and a IM 11 doesn't even have knobs on the zero & ohms adjuster - and one of the two range knobs is scratched. I have larger vtvm, antique stoff from my childhood days, Grundig, Sennheiser, Rohde & Schwarz, Metex - more vtvm than i have space - hard to resist that analog stuff 😄- but i still wanted such a cute little one. Or maybe two, we'll see 😂

[@ricke573]

As already noted, those are precision resistors, probably wire-wound -- meaning you have a long length of wire with a known resistance per foot, and the correct number of turns are wound on the core to make the desired value. Resistors like that are usually good to 0.5% of their listed value.

[@Dutch-linux]

pp is volt peal to peak and with the ac going to only 50 volts ... it goes higer you just have to calculate depending what range you are in on the setiing knobs ....

[@goddessesstartrekonlinefle3061]

That is a thing of beauty! It looks like it might even have been hand assembled? Oh yes. Right you said it was probably a kit :D. What a great deal! Ron, you rock for leaving it original and resisting changing the caps \o/ :D. It will definitely reform with use (they just don't build them to last in the modern age like they did back then).

[@vhm14u2c]

Gonna need a GLIM substitute I guess, Ron 🥂 awesome price BTW in tubes alone, and thanks for sharing!

[@Dutch-linux]

you are right the calibtation is done after the tubes are installed why there are those calibration pots a vtvm is usulaay 1000 times more accurate then a digital meter these days

[@AmateurRepairTime]

Thank you

[@werner.x]

It's easy to pretend though, that it may be more accurate, since you'll have a hard time to read the 10er digits, not to speak about the 100s on an analogue scale.

[@Dutch-linux]

the tubes are for the high impedence input the higher the impedence the better it is to measure accuratly

[@AmateurRepairTime]

Thank you

[@WilliamBallad]

The battery is used as a dc supply for the ohms test and not needed for the other measuremente. The black cube that is loose is the power line rectifier. It could be replaced with a silicone rectifier. The tubes are used as a balanced amplifier and are not critical The 6al5 is for the AC measurements.The small circle on the meter scale is a center zero for null measurements.

[@MartysRandomStuff]

Did that battery say 20 cents each? That must be the original battery. Alkaline batteries do way more damage vs the old zinc acid ones, so I'd leave the old one in. Love how they listed all the specs for the PC board, how it was etched, the thickness of the copper, and the type of board used. My dad and uncle built loads of Heathkit stuff back in the 60s and 70s. They even sold kits to build TVs. Pretty sure my dad used his Heathkit car battery charger up until the late 90s.

[@AmateurRepairTime]

That's pretty awesome, I didn't know they made T.V.'s! Now I have something else I have to find...

[@robtitheridge9708]

The reason for useing a VVM is it has noeffect on the circuit under test

[@AmateurRepairTime]

Thank you

[@jasonudall8614]

The " tubes" are there for making it a high impedance input. Which is a technical thing from moving coil meter days.. Basically the impedance of the meter on simple moving coil meters effects the reading you get from some voltage inputs.. The impedance of the source means you get an jncorrect( low) voltage reading and depending in your meters "burden " on the source the error varies. To address this we now use amplified input "meters".. First valves( tubes) later FETS and today more complex solid-state..all increasing the input impedance--resistance.. One tube is a rectifier..involved in the powers supply of the amplifier ..tgd other amplifies the input signal..not so much voltage gain but impedance increase.. Now my valve circuit theory is very sparse and from long ago.. But the amplifying tube will be some low or "unity " gain circuit..configuration circuit..by asking a low gain from tube you in effect don't suffer from the variable "gain" of the tube.. Those resistors. Wire wound .. Platinum wire ... Stable stable stable. The calibration of the tube circuit is by those internal potentiometers The zero adjusts..are from outside

[@AmateurRepairTime]

Thank you that makes some sense

[@jasonudall8614]

@AmateurRepairTime your welcome...I am still watching the vid..I see the "instructions " are pretty thorough..

[@GutsyGibbon]

Nice Ronnie, now back to my pinball machine.

[@Dutch-linux]

the minus dc setting is so that the meter wont go to the negative but shows the the needle go positive as analog meters cant do negative like the digital meters do the digital meters will show a minus sign a analog can't do that .....

[@juise15]

July 83, that was a good year.

[@FlickLives]

The squiggly brackets on the meter display are called, wait for it, squiggly brackets, curly brackets or braces. !

[@AmateurRepairTime]

Hahaha great

[@zyxxy]

It's close enough for rock n roll is an old saying among guitar players. Also the name of an album by 70's rock band Nazareth.

[@AmateurRepairTime]

That's a good one!

[@carlubambi5541]

Good meter .Its a VTVM

[@FireandFrostHVAC]

Man oh man, I’ve been looking for a decent VTVM for my bench for a long time with no luck (I live in communist Canada where you’ll never find any decent old gear), and here you find one for $5… Not gonna lie, I’m often jealous of my American neighbours… Btw, it’s a good idea when using that meter to make sure that your DUT is on an isolation transformer, just in case you didn’t know that, if not you’ll create a ground loop and blow things up… 😁 Good video, thanks!

[@eDoc2020]

You might want to recalibrate the meter again using a different reference source. When you have very old batteries like this the internal resistance is in the millions of ohms, making the voltage unreliable. It could be 1.4v when measured on one meter and 1.2v when measured with another. Maybe use an arcade PSU that's been adjusted to 5.00v.

[@1dave301]

They would be precision wire wound resistors. I used vtvm's back in the 70's, but those vintage details have been pushed (overwritten) out of my brain.

[@dlschgo]

"Good enough for the girls we run with. "--South Main Garage on KZbin.

[@CNKayutube]

CRC is fine the Deoxit snobs that pay 25$ for a 4oz can are nuts i cant see paying snap on prices for a consumable , oh wait i do have a few of those cans ( put me in a straight jacket)

[@RPike-bq3xm]

I think those used two 12AX7's which are going for a pretty penny.

[@eDoc2020]

One tube is the 12au7 which is a bit less valuable than the ax7. The other is the 6AL5 which is worth very little.

[@ZBot-bq7yr]

👍👍

[@michaelvonharten7633]

Great deductive reasoning again young man, you learn far move figuring things out youself. PS solder still doesnt have a silent L 😁

[@AmateurRepairTime]

Pronounce battery for me real quick

[@michaelvonharten7633]

Good point. I'd say battry silent E. I'll shut up about it now 😔😔😔😔

[@CrucesNomad1]

It is a beautiful multimeter lol. Need a new tube.

[@torymartinez2439]

it says rosin core solder is recommended

[@timmooney7528]

Might want to pull that battery out of there before it leaks or bursts.

[@AmateurRepairTime]

We mentioned that lol

[@timmooney7528]

@@AmateurRepairTime I typed that out right before it was said on the video. I've had my share of bad batteries in devices. Old habits die hard.

[@ray73864]

Too infinity, AND BEYOND! :D

[@naytch2003]

Joe told me what was wrong with it..shit what did he say(!) Crap i forgot 😫

[@markjackson1444]

It’s also close enough for folk music! …no offense to all the folkies. Very interesting Ronnie. … but I’m still pretty flakey on what this actually does… but hey, that’s pretty normal for me.

[@Dutch-linux]

1.5 volt is the 1.5 volt scale and the rx1 is the 1 ohm scale the 5 volt is the 5 volt scale the rx 10 is the ten fold of the 1 ohm scale etc etc

[@WreckDiver99]

Meh...close enough for Government work...well...actually? You FAR surpassed government work. If you were doing that, you'd have failed miserably, blamed it on others, and declared a job well done on a success!

[@AmateurRepairTime]

Then raised your taxes!