TV-7 Tube Tester Calibration, Repair, and Service - a Practical Guide - Part 1

Looking forward to the wrap up of the single ended tube amp. I know you stay pretty busy but I hope it is on your plate.

Very easy to follow. Many thanks. Decided to purchase a Marantz 2275 and recap it myself because of your great videos. Thanks for doing this.

Roger Waters is doing tube tester repair? ;) I thought he was touring... Good to see you are producing videos! Been a while since your last. Thanks Mark!

Hi Mark, Just wondering on your thoughts on the Hickok 752?

Hi Mark, thanks for all the great videos. I'm in the process of recapping a Blaupunkt radio from the 1950s and have run across capacitors with marking I don't fully understand. For example: the caps are marked " 50/20 125V" The 125V I understand but I'm not sure how to read the "50/20" part of the marking. The caps in question are small and appear to be foil and paper in a clear plastic tube. Any help in reading the value would be appreciated.

Hi Mark, absolutely great and easy to follow video. I contacted Dan Neilson regarding buying the calibration tubes. He advises that he doesn't have them. Any ideas on where else I could purchase them and or would you consider making a set and selling.

Cheers

I thank you for this very helpful and clear instructive video to align my TV7D/U ............. i have only one problem , i can't find a fuse lamp anymore in Belgium , can you help me ?
Greetings from Belgium , Have a nice day Mark.

Mark, thanks for the video. I've been borrowing a TV-7DU from a friend for over a year and want to calibrate it for him.

for the TV-7 U I can not find a R134 and in the manual for the Military aliment it states R124, so that would be the one I switch with a POT? For mine the line adjust is at 60 and easy to do, but all the filament voltages are half what they should be

Thank you.

Great video. I just picked up one of these and used the old military manual to calibrate the voltages. I cannot find documentation on the gm calibration procedures in any of the online resources. If you don't mind telling, where did you get this procedure from? Sincerely, Steve

I was in the military 20 years(1961 to 1981) ground radio communication. All types of equipment. Used the TV-7 a lot. Back in the day of tubes were used a lot!

Does a TV-10 set up the same way as the TV-7 ?

Great, thinks, but nothing for the fist one the TV-7U plase? What's the difference?

Thanks and please...Sorry for my bad English

Excellent demonstration.

Can you please elaborate more about the R130 power resistor? It makes me apprehensive about buying one that needs calibration. I googled it, & there seems to be replacement resistors that don't look like the original that came with the TV-7.

Interesting video. Helpful in many ways. Unfortunately he will not respond to any questions. I even purchased his set of calibrated tubes on ebay and wouldn't respond to any question on ebay either. Also, the 6L6 metal calibration tube he sold me was very rusty and looked like it was at the bottom of the ocean for a long time.

It would be nice if there were this detailed calibration video for testers like stark 9-66/hickok 533 testers.

Working with this on my new (to me) TV-7C/U. It's working now, but obviously needs the updates and calibration. I was surprised to see how small the case is relative to my big Hickoks and I notice that it generates a LOT of heat just idling on the bench. What's your opinion and experience with putting in solid state replacements for the 5y3 and 83? I would think it should reduce the power consumption and thus the heat by some factor.

Hi, seems that in TV7UB, there's no 13? pot on the chassis above R134 to calibrate/control the bias, like on the UD version. On my model, there's no 3rd pot like in the video. In addition, the last number R13? can't be seen, so it's hard to know where to check. Any idea ? Regards from France

You don't blow air in meter it will distort the fine springs. The best is submerge meter enough to cover pivot in iso alcohol then let air dry for hour. I would do that to your meter should free up the sticky pivot

Send meter I will repair it so you will have a spare :)

Hi Mark, we talked over thru ebay regarding the tube calibration set, I sent you email, you might not get it or is in your spam folder somewhere. Ebay thing didnt work, ebay support asked me to ask you to relist the item specifically for me. Obviously youre super busy guy wouldnt even think about that. Can I send you paypal instead? let me know. novyan at msn dot com

How do you make a set of calibration tubes?

Fantastic video, thank you for sharing your knowledge. I am working though the process on my TV-7 (the original with no adjustment pots) and everything was within a hair of where it should have been, close enough i am not going to worry about it. BUT i got as far as testing the Plate voltages as per the original calibration manual with a 375k resistor and i'm seeing 188v instead of 150v. The manual goes down a rabbit hole of swapping the plate wires around for each rectifier tube, but curious if you have any better ideas before i go there?

Bias @22 = 2.86v
Bias @75 = 25.26v
Bias @100 = 39.04v
Screen = 125v instead of 130v
Screen = 54.3v instead of 56v

Plate w/375k = 188v instead of 150v

Filament voltages with line test centred,
120.2, 76.3, 53.8, 36.7, 26.45, 19.50, 12.40, 9.99v (10v setting), 7.54, 6.30 (6.3, 5.20, 4.31, 3.24, 2.71, 1.994, 1.273, 1.090, .728

How would I build one of those diode circuits for my hickok 752 it's called cr1?

Surprised they didn't have a bias fuse in that tester would of saved that control. My hickok 752 has one

what to say..... clear explanations, also your pronunciation is slow and clear (i'm italian, so it is not always easy to understand people that talk quickly), about Video quality... another great video and also added with writings that for sure helps understanding ! i'm going to subscribe your channel. Thx for all the explanations!

Strange that military tester would have sticky meter pivots.

After a year of searching and pondering, I finally just pulled the trigger on a TV-7D/U (due to arrive soon), so Iv'e delved deep into related videos. Thank you, Mark, for your extremely informative videos and generous efforts to educate on so many topics.

Thanks to Mark for this informative and overall fine instructional video, my remaining question? How do I place slide reinstall the Hickok TV7 DU back into the chassis? (no kidding)

Hi Mark, thanks for your video. My TV7 D/U can only get 13v for high screen, when I adjust R110. Can you advise which part may be wrong. Really appreciated.

how do I know if the unit is out of calibration?

hickok 600a is pretty similiar. Ive got one that will not test rectifiers when pressing the p3 button. I would also guess p2 functions do not work according to schematic

A fix for meter is take cover off and soak bottom half in IPA for 30min and let dry for 1 hour

Great video, very informative and helpful. Just a note, your mention of the TV-7/U series going back to the early 1960's.. the tester actual dates back to the early 50's. My TV-7/U is from 1953 and my military tech manual is dated 9/53.

Un amigo radioaficionado decidió retirarse a descansar y me regaló un aparato de estos.

Dice:

TUBE TESTER TV-7B/U
SERIAL No 525
Forway industries INC.

Lo conecté a la energía eléctrica y enciende perfectamente.

Está en venta.

También me regaló u otros elementos cables y antenas.

Y más de 20 bombillos de vacío

Ok ! You made me do it ! I just got a TV-7D/U on eBay !!! Good price too and the case isn't beat up ! I'm going to watch your video again, take notes and make a detailed instruction manual as per your simpler method ! Thanks Mark, love all you do ! Curtis

I got a TV3 C/U arriving Monday; can I apply some of this tutorial on that (Or are they totally different).

Any ideas what I could get for testing EL34 & 12ax7? I wanted to get the Orange VT1000 but they are discontinued. I was looking at the B&K 606 & the 747 but every seller seems shady & the prices are up there considering I'll need to re-cap it & change some resistors & calibrate it. It's for personal use just to keep an eye on my tubes.

Impresionante trabajo !!! 👏👏👏👏👏👏👏

Excellent videos. Have you done a calibration of Hickok 800?

great tutorial!

Thx. Great content!

Bought a recently repaired/somewhat updated (guy couldn't have cleaned the contacts as two selectors were kind of sticky/stiff until I cleaned them with Deoxit) TV7-D/U off an eBay seller recently and for the most part, readings on tubes pretty much matched what I was expecting, esp. triodes like 300b and 2A3, close enough anyway. Rectifiers were good, GZ34s sold as matched sets at 60/60 came in at/around 60/60. Thought I'd check the calibration anyway and meter checked out at 202mA, power resistor (about 9.35k), went ahead and replaced the 47 ohm resistors anyway with better quality vishay fireproof ones (i'm not a fan of the cheap Chicom resistors with the enamel that flakes off); a set of tubes I bought through Blueglow Electronics on eBay showed voltages (pins 8 and 4) were off by about 1-2 vdc on initial checks, took a few hours to run through the tests, calibration steps and everything is spot on now.

ONE question. Why not replace that multi-tapped power resistor with two precision high-wattage linear potentiometers? THAT setting High/low screen voltages was tedious as anything and the two tabs I had to insulate from each other with a piece of heat shrink tubing they were so close. Actually thought about reversing all the wires and using the other side of the power resistor but I'll just use the tester as it and see how it holds up.

Thanks for putting this together for us.