I love vacuum tube electronics they are so much more reliable than solid state. They last almost forever when cared for properly. Can you please do more repairs like this in the future they are very interesting.😁
Good job Tanner! You did a very good job with the restoration AND explanation of the VTVM. I am restoring the same meter as I write and found your guidance very helpful especially selecting the 1N4005 diode. I will be using mine to do an alignment on an old Hallicrafters HQ-180 shortwave receiver. Just had to say thank you for such a great restore of the VTVM. Mark (N2DMI)
There's something about old electronics that you don't get with modern equipment. It's the fact, that you can see every component in the circuit and easily figure out what they do. The circuits are also usually exceedingly simple and consequently troubleshooting is almost always a lot easier than it is on modern equipment. Sure, they lack the fancy color LCD displays and different functions that are only possible with the help of a microcontroller, but those old things had to be made to serve a single purpose and they did it well with a clever use of components, that were available at the time.
Tanner , It is refreshing to see a young brilliant student like you so involved in electronics. I have one suggestion for you in regards to using this meter to measure ac line voltages. Although the power supply of the meter is isolated through the power transformer, the black lead or common on many of these old VTVM's is connected to the chassis . They also use a two wire line cord. If you connect the black or common lead to the hot side of the line , the case of the meter will be at line potential . If you touch the case you would be touching line potential . I suggest if you work with any line operated devices, especially older ones, get an isolation transformer . A variac is an autotransformer and does not isolate you from the power line. Keep up the good work Tanner, you have a bright future .
Great video! About 8years ago I purchased one of these meters on ebay, when it arrived from America ( I'm in the UK) it was in a bad condition, some of it due to poor packaging, even the circuit board was broken in half! But I really wanted this meter, I repaired the board, replaced the parts that needed replacing and have been using it ever since! I'm an old guy and I build my own vacuum tube amplifiers, I have quite a few fancy modern meters but this one is my favourite go to meter!
Hi Tanner your video about vacuum tube multi meters has encouraged me to repair and build vacuum tube electronics myself thank you for making your videos they are amazing
Hello, TT! I have watched your vids for a few weeks now and have no regrets. I am 14 years of age as of right now. I am currently building a dual mot SGTC. I have done electronics for about 2 years and my goal is to go to MIT or Cal Tech and get a degree in electrical engineering. Just wanted to say, your not alone, there are plenty of other young engineers. If only all of the could come out. Anyways, you have definitely earned my subscription and I wish you the best of luck!
That one is in beautiful shape! Replace all the electrolytics and measure each carbon comp resistor. A solid state replacement is made to replace the battery forever. This is very cool.
i dont mean to be so offtopic but does someone know of a trick to get back into an instagram account..? I stupidly lost my password. I appreciate any tips you can give me
@Kai Kairo thanks for your reply. I got to the site through google and I'm in the hacking process atm. Seems to take a while so I will reply here later with my results.
Very nice presentation. You may have noticed that the two triodes are connected as a current mirror - two cathode followers. As the left triode is biased further into conduction, the right triode reduces its cathode current proportionally leaving a differential voltage across meter and series cal pot. This current mirror has good common-mode rejection so that any variance in a.c. line voltage is cancelled and will not cause imbalance in meter differential voltage. Op-amps do very much the same thing, but with a more precise effect due to their very high gain.
Never ever work on vacuum-tube electronics without first discharging the electrolytic capacitors. If you are working on powered-up high-voltage electronics, only use one hand to hold probe. Keep the other hand away from the gear.
Also, you should be using an isolation transformer - not one of the hospital grade versions, but a real Technician Grade version, that truly isolates the primary and secondary sides.
@@howardhiggins9641 the internal circuits on the secondary of its power transformer are chassis ground referenced and so just clip scope ground to the chassis and all is okay.
I have a model v7a and the needle jerks around while it's just setting there. Any idea what might be the problem? I'm replacing the 12au7 since it reads low on the tester. I've never seen anything like it.
I would have ordered the axial lead capacitor. It just looks too rigged to solder in radial leads in old equipment, although I see it all the time, just doesn't look right. The new axial lead caps don't look the same, but they do look like they belong there and avoid the rigged look. This does not reflect on your skill, I just think neatness counts. A 16uF at 450 V should be about $6 from the many online supply businesses like Antique Electronics Supply.
I thought that the microfarads had to be exact? and that on voltage you could go up in value for the capacitors? why did he use a 20mfd capacitor? anyone know?
Tanner i have some awesome vintage hp and heathkit meters that are nice but need some repairs. I'm willing to gift them to you if you can make use of them. Keep doing good things....
Hi Tanner Very good video I just picked one of these VTVM same model would you do me a big favor and direct me to the manual and schematic or share yours thanks jk
Oh no! Those cats love to mess with electronics haha! I would try supergluing the parts together, see if it looks any good. If not, it will run fine without the cover, just make sure to keep any air currents away from it, they will interfere with the needle. If you are really feeling adventurous, you could try making a new one by bending plexiglass. Old heathkit parts are hard to come by these days... Good luck!
@@TannerTech I have most of the piece's. If I had the time I could make a mould and make a new one from epoxy. I'm so sad my cats have done this. It seems we need a supplier for the heathkit face plates. Perhaps I could start manufacturing them.
You don't "tune" meters, you CALIBRATE them. Potentiometers without knobs, are NOT knobs. Suggest you take a Metrology class to learn the correct terminology and procedures. Don't give up trying, you'll get there..
Nice video, the logo on the bottom of the box is actually Union Bag Camp Paper Corporation.
I love vacuum tube electronics they are so much more reliable than solid state. They last almost forever when cared for properly. Can you please do more repairs like this in the future they are very interesting.😁
lol. i recently found an old multimeter like this with the same problems. now i know what to do. thanks!
It’s funny, I refurbished and sold many Heathkit V7A and V3 meters, all of them very similar to the IM-11 outside and inside.
Good job on this!
Do all the old VTVM's used a 1 meghom resistor for the probe?
Thank you
Good job Tanner! You did a very good job with the restoration AND explanation of the VTVM. I am restoring the same meter as I write and found your guidance very helpful especially selecting the 1N4005 diode. I will be using mine to do an alignment on an old Hallicrafters HQ-180 shortwave receiver. Just had to say thank you for such a great restore of the VTVM.
Mark (N2DMI)
There's something about old electronics that you don't get with modern equipment. It's the fact, that you can see every component in the circuit and easily figure out what they do. The circuits are also usually exceedingly simple and consequently troubleshooting is almost always a lot easier than it is on modern equipment. Sure, they lack the fancy color LCD displays and different functions that are only possible with the help of a microcontroller, but those old things had to be made to serve a single purpose and they did it well with a clever use of components, that were available at the time.
Tanner , It is refreshing to see a young brilliant student like you so involved in electronics. I have one suggestion for you in regards to using this meter to measure ac line voltages. Although the power supply of the meter is isolated through the power transformer, the black lead or common on many of these old VTVM's is connected to the chassis . They also use a two wire line cord. If you connect the black or common lead to the hot side of the line , the case of the meter will be at line potential . If you touch the case you would be touching line potential . I suggest if you work with any line operated devices, especially older ones, get an isolation transformer . A variac is an autotransformer and does not isolate you from the power line. Keep up the good work Tanner, you have a bright future .
A legendary piece of hardware, and an awesome video. Keep them coming!
Great video! About 8years ago I purchased one of these meters on ebay, when it arrived from America ( I'm in the UK) it was in a bad condition, some of it due to poor packaging, even the circuit board was broken in half! But I really wanted this meter, I repaired the board, replaced the parts that needed replacing and have been using it ever since! I'm an old guy and I build my own vacuum tube amplifiers, I have quite a few fancy modern meters but this one is my favourite go to meter!
Hi Tanner your video about vacuum tube multi meters has encouraged me to repair and build vacuum tube electronics myself thank you for making your videos they are amazing
Hello, TT! I have watched your vids for a few weeks now and have no regrets. I am 14 years of age as of right now. I am currently building a dual mot SGTC. I have done electronics for about 2 years and my goal is to go to MIT or Cal Tech and get a degree in electrical engineering. Just wanted to say, your not alone, there are plenty of other young engineers. If only all of the could come out. Anyways, you have definitely earned my subscription and I wish you the best of luck!
That diode that you removed, was a selenium rectifier.
Incredible battery! That thing has to be over 30 years old! 😂
That one is in beautiful shape! Replace all the electrolytics and measure each carbon comp resistor. A solid state replacement is made to replace the battery forever. This is very cool.
i dont mean to be so offtopic but does someone know of a trick to get back into an instagram account..?
I stupidly lost my password. I appreciate any tips you can give me
@Emerson Fox Instablaster =)
@Kai Kairo thanks for your reply. I got to the site through google and I'm in the hacking process atm.
Seems to take a while so I will reply here later with my results.
@Kai Kairo It worked and I actually got access to my account again. I am so happy!
Thank you so much you saved my account!
@Emerson Fox Glad I could help xD
When you started pulling it apart, I thought to myself "where's the warning about draining the capacitor". lol
Very nice presentation. You may have noticed that the two triodes are connected as a current mirror - two cathode followers. As the left triode is biased further into conduction, the right triode reduces its cathode current proportionally leaving a differential voltage across meter and series cal pot. This current mirror has good common-mode rejection so that any variance in a.c. line voltage is cancelled and will not cause imbalance in meter differential voltage. Op-amps do very much the same thing, but with a more precise effect due to their very high gain.
Very interesting and informative video.
Very good video.
always consider cleaning potentiometers and tube pins, ensure maximum cohesion!
- where are you finding this stuff!?
I did build two of those about 60 years ago
Nice vid man!
Thanks man!
Never ever work on vacuum-tube electronics without first discharging the electrolytic capacitors. If you are working on powered-up high-voltage electronics, only use one hand to hold probe. Keep the other hand away from the gear.
Also, you should be using an isolation transformer - not one of the hospital grade versions, but a real Technician Grade version, that truly isolates the primary and secondary sides.
@@howardhiggins9641 the internal circuits on the secondary of its power transformer are chassis ground referenced and so just clip scope ground to the chassis and all is okay.
I have a model v7a and the needle jerks around while it's just setting there. Any idea what might be the problem? I'm replacing the 12au7 since it reads low on the tester. I've never seen anything like it.
Hi Tanner. Does your transformer run warm at all?
I would have ordered the axial lead capacitor. It just looks too rigged to solder in radial leads in old equipment, although I see it all the time, just doesn't look right. The new axial lead caps don't look the same, but they do look like they belong there and avoid the rigged look. This does not reflect on your skill, I just think neatness counts. A 16uF at 450 V should be about $6 from the many online supply businesses like Antique Electronics Supply.
I thought that the microfarads had to be exact? and that on voltage you could go up in value for the capacitors? why did he use a 20mfd capacitor? anyone know?
What model is that Heathkit VTVM? anyone know?
Thank you
Tanner i have some awesome vintage hp and heathkit meters that are nice but need some repairs. I'm willing to gift them to you if you can make use of them. Keep doing good things....
Thank you! I am pretty busy right now with schoolwork and such, but I would love to fix them later. Do you by chance live in California or Boston?
Hi Tanner Very good video I just picked one of these VTVM same model would you do me a big favor and direct me to the manual and schematic or share yours thanks jk
www.rsp-italy.it/Electronics/Kits/_contents/Heathkit/Kits/Heathkit%20IM-11%20VTVM%20manual.pdf
No problem! Does this one work?
hey now, never check a battery voltage without a load!
I live in hawaii
I have one, a V-7 that my cat knocked off the table and busted the clear plastic dial cover. I have most of the pieces, but not all. Any suggestions?
Oh no! Those cats love to mess with electronics haha! I would try supergluing the parts together, see if it looks any good. If not, it will run fine without the cover, just make sure to keep any air currents away from it, they will interfere with the needle. If you are really feeling adventurous, you could try making a new one by bending plexiglass. Old heathkit parts are hard to come by these days... Good luck!
@@TannerTech I have most of the piece's. If I had the time I could make a mould and make a new one from epoxy. I'm so sad my cats have done this. It seems we need a supplier for the heathkit face plates. Perhaps I could start manufacturing them.
@@sarahhoward9081 That would be cool if you started manufacturing them! I have one that is broken as well.
why is your username tanpa? :'D
You don't "tune" meters, you CALIBRATE them. Potentiometers without knobs, are NOT knobs.
Suggest you take a Metrology class to learn the correct terminology and procedures.
Don't give up trying, you'll get there..