Weston 981 Type 3 TUBECHECKER Repair, Modification, And Alignment Procedure!
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- Опубліковано 30 вер 2023
- Weston 981 Tube Tester From 1954! Let's repair, modify, and align this tubechecker so it performs like it's brand new. To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: / mrcarlsonslab
Electronics Education
#restoration #electronics #repair - Наука та технологія
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
Having repaired a number of Hickok testers, I'll add some info about a couple things that Ned didn't cover here. First of all, *Never* spray the switches and controls with any kind of contact cleaner that leaves a residue, lubricant or "preservative". I don't care what anybody says, or what the directions on the can say, don't do it! I have seen tube testers ruined by people spraying switches and controls liberally with contact cleaner because the chemical residue soaks into the phenolic wafers, and especially on units like this with a sophisticated leakage test that reads in Megohms directly on the meter, you risk creating leakage paths that could create flukey tube reedings or show interelement leakage on tubes that have none. The problem might come and go with temperature and humidity as well ,and once you've saturated the switch wafers, which are mix of cellulose fiber, wood pulp and resins, there's probably nothing you can do to remove it. It's best to spray things a little at a time with pure alcohol, and try to make sure any grease and dirt that is dissolved by the alcohol gets blown off and away from the switches with air pressure. If the tracks on the switches are sufficiently oxidized that you must use Deoxit similar, apply a tiny drop exactly where you need it with a syringe, toothpick or dental pick.
In the case of Hickok testers, which are very different from the Weston circuit, calibration instructions always said to use a voltmeter with a 1k ohm per volt impedance (except for measuring the grid signal) . Taking the readings with a digital meter won't load the system down the way that it was when the factory checked the calibration, and so all the voltages will either seem to read high, or youll end up adjusting the machine so that the voltages appear to match the schematic/service info, but they'll actually load down and be lower than you think when you try to test tubes on the machine. Put a 150K to 200 K resistor across the digital meter probes and that will load the tester down similarly to how it was measured and calibrated at the factory (Hickok B+ is 150 volts). The grid signal however can be measured directly with a digital Volt meter because the factory would have used a VTVM, a vacuum tube volt meter, which is very high impedance.
Very impressive that it has held the factory alignment after so many years.
I bought a new TV so today Mr C is bigger and still awesome
Thank you so much, I have one of these, it's the version with the ballast tube and no overload lamp but otherwise the same. This is the calibration guide that I have been waiting for!
Earlier this year I was looking for a 981-3 for several months on eBay. Then at a unbelievable price, $100.00 a Weston 978 popped up. The 978 looks nearly identical to the 981, but it was specifically made for the Aeronautical Service under a US Government contract. So that meant that it also had a ton of phenomenal documentation created for it as well. Unlike the 981 that lacks a lot of critical documentation. I compared the 981 schematic to my 978 and they are similar except for a few things that were labeled differently but did the same function. From what I can tell the build quality is exceptional as well something you would expect for a government contract. I checked this morning and my 978 already has the modification that he did to his 981?? It also appears to be done at the factory??? If so, why did they not do this in the 981?? In any case it is interesting to always watch his videos, and continue to learn things!!! Having 6 tube checkers now in my collection, and over 1000 tubes in my inventory it is always fun to pick the right checker for the right tubes being checked. Mine are all calibrated but still can show different results..
"Like they say, a person who wears One Watch knows what time it is, a person who wears 2 watches is never sure!" 🙂
Thanks for the vintage electronics ASMR video.
I've got one of these! It was given to me in the 1980s and sat for some time before a going-over. Works great, still.
Paul, I was so impressed with this tube checker that I ended up buying one. I have two Precision Apparatus Company tube checkers that I restored. Both work well. However, I've always been impressed with the quality of the older Weston meters with the mirror scales. And I am a New Jersey native. Both reasons that influenced me to buy the Weston tube checker.
A little tip regards to the removable multimeter unit. 3D print an adapter and attach it to an flexible arm. Easier to display it in videos etc. keep up the good work. Love your videos! :)
Seems like a waste of time when you can just put a magnet on a desktop trios and attatch it to the magnet on the meter face.
Hello from MN, Mr. Carlson. Thanks for the great content!
That tester has a socket for acorn tubes. They were small baseless VHF/UHF tubes introduced in the 30s. Pins for the elements came out around the perimeter and ends of the tubes, needing a flying lead for some connections. As I recall the tubes numbers were 954, 955 etc. That may be what the 'broken' lead is for.
Thanks.
I appreciate you sharing your hard earned knowledge. You are one of my favorite UA-cam creators. This is true in spite of my not being an electronics enthusiast.
I appreciate that!
Thanks for this video. Very interresting.
My pleasure!
Wow! Another really good looking piece of equipment. One thing I noticed immediately was the original solder joints. I think the motto for soldering back then was "the bigger the blob, the better the job". Now for your next challenge. Restore a Heathkit assembled by someone who though they knew what they were doing.
Thanks Paul.
It was very pleasant to hear your report again.
See you next time.
73 pe1krx
Anyone else get a warm feeling, for the minds, designs and builds that went into these machines? There it is the knowledge of the time, expressed in machinery. Hats off to the old chain smokers, with starched shirts and a wife taking care of the kids at home, while the husband hammers down whiskies after wo, at work.
Excellent. Tons of fun. Thanks a bunch for posting this. Much appreciated.
Thanks for your encouraging inspirational videos. Have a great day and keep up the good work!
Thanks for your kind comment!
Any time!@@MrCarlsonsLab
Thanks for sharing, Paul.
Thanks so much, Paul. I am a strictly solid state and digital guy, trying to learn..."Tube Technology"! Lol
Not sure that blue wire was snipped as some insulation is a little stripped back, and the other end looks like it has some kind of heat shrink or connector on it, so it may be from factroy, but it looks more like its pulled out of the joiner it was meant to be connected to rather than being snipped. That's just how it looks in the video :)
Love these long form videos. Always a good day when Mr Carlson is doing an analytical repair.
I remember using the old tube tester at the local Rexall Drug Store as a youngster. 😉
another masterpiece rich in knowledge
Always good to see another video drop. Thanks Carlson !!
I remember back in the good ol days, yanking all the tubes out of your tv or radio ...
going down to radioshack or Montgomery ward and they had a tester...
thumb through the lil book and if you was lucky they even had the tube or the equivalent.
Excellent Mr Carlson👍👍 The fixes were extremely simple but the alignment was involved and having to do it with the unit under power would be stressful for most. The wiring was dressed neatly so someone took time doing that, zip ties were a give away.. Great video as always, much appreciated, thank you. See ya soon.
Excellent video of a great piece of gear.
Paul, you have a mutual conductance tube tester is one of the very few that can test the Acorn tubes, I notice that right away into the video. The strange socket just to top right of the meter accommodates the acorn tube. The pin plug wire is for acorn tube with a top connection pin, like the 954 & 956. Acorn tube numbers that I'm aware of, range from 954 to 959. I have a Precision emission tube tester that can check the Acorns.
Most of the better Hickok testers can test acorn tubes, and even subminiature pencil tubes. I have a Hickok 752A that can test anything from 1920's-30s 4 pin radio tubes all the way up to 12 pin compactron tubes used in 1960s color TV sets.
Great opening shot of your shop ceiling.
Do you like ceilings?
Not particularly, but I see them often when ppl frame the shot too high.
Oh it's an impressive collection, one that I respect. I watch all of his videos and they are well made and informative. It's that opening shot that I think looks silly. This huge shop with this tiny man sitting in the middle with a huge ceiling overhead. Why not move in closer, frame Mr. Carlson properly and let the shop present itself over time with different shots?
I have atomic starburst Xmas ornaments hanging from mine and large gold spray painted letters "w1rmd" in "your grandmothers handwriting" protruding from the wall about six inches from an all black wall (in an all black room). The giant wall size window has orange and seafoam green paint around it like Howard Johnson's. Still working on the led edge lit maps for the other wall. 1960 NASA fans and Charles Phoenix would be proud! I LOVE your light bulbs! @@MrCarlsonsLab
Hey "TD75"... Your negativity didn't work! People here on this channel are intelligent, and don't play along. Do you know that you create your own history on UA-cam by the comments you leave. All the comments you seem to leave here are "negative." You know, when you do this, channel owners can "Shadow Ban" you from their channels. That means: When you leave a comment, only you see what you have posted, but no one else does. If you have been banned on a channel, when you log out of your UA-cam account and look for your comments, you won't find them. Pretty tricky right! I haven't banned you yet, "Because I'm Tolerant," but if you keep leaving nasty and negative comments on my channel, you will be banned. This also helps UA-cam realize that they may need to put your future comments (on other channels) in a review folder, so then channel owners (like myself) will then have to manually "OK" your messages for them to show in the comments section. Again, only you will see your comments until your messages get an "OK" from the channel owner, and released manually from the review folder. Are you wondering how many channels have done this to you now?
Really nice valve tester. Still accurate after all these years. They knew how to build equipment back then.
Weston made all types of great instruments back in the day.
You're a Brit. You call tubes valves.
@@foureyedchick Yes I'm a Brit, but it is only Americans and Canadians that call them tubes and not valves. LOL.
@@frankowalker4662 And when you google "Röhrentester" you will actually find a nifty DIY tester from Hans Borngräber :)
As usual Paul, excellent content!
Much appreciated!
Paul have you ever worked on police scanners and have you ever thought of doing a video on the subject I would very much think it would interesting to talk about how first police band recievers work like the band on what was used all the way up to explaining trunk lines that are used today you would do a fantastic job of it I am shure .Paul like said before your are a natural educator and you do a great job of it I like the content of you videos
My Weston is similar to this one. Some variation on panel markings. Mine has a toggle switch for screen settings were the overload lamp is at on yours, instead of a Gm test toggle, mine is labeled gas test, Anode voltage (EP) is labeled V,H,S,M,L,N . Above the meter is sockets for transistors. Everything else is the same. Thank you for this video.
id love to see you restore a tube tv
I have a thing for old tube checkers. Working on a Supreme AAA-1 Diagnometer now.
Nice tester! Somewhat different to the "Hickok class" often seen in the military types like TV7 and many more
As always i'm hanging on your lips how you explain and tell about electronics and these type of tubecheckers we don"t see a lot in Europe , i have a AVO Mark 2 and not so good as the Weston 981 i think.
I'm just sitting here screaming Paul burnt resistor! That resistor on the bottom of the screen right here at 6:45 looks blown up. Although I know it could possibly just look that way because of flux.
That's the way those resistors look. That one looks like it's in new condition too.
The 6K6 is a low power output tube, somewhat similar to the 6V6. It was used to drive the reverb tank in the original 1950's Fender reverb unit that you probably heard being used by many surf guitar bands.
I use the modern equivalent of plumber's asbestos pads or a genuine animal skin shammy to lay over roll charts or grille cloths or speaker cones and especially VERY expensive guitars. The shammies work great. I have burned a couple small holes in one shammy and it's still usable. It really stinks to high heaven, but they will take a hot soldering iron laying on them for a decent period of time, and even when they do start to smoke, the damage is still minimal. I usually carelessly toss the shammy on the soldering iron while I am swapping out guitars on my workbench and then my shop fills up with acrid stinky smoke.
Very nice tester, thanks for the video. Wondering if circuit is simular to my hickok 752. Looks closer to a B&K tester design. If needle deflects but then goes back to 0 thats normal. But yah yours has issue, usually bad cap or drifted resistor
Wonderful instructional video. I started restoring audio generator Jackson652, but my schematic doesn't have voltages on it, do you have it eventually? Thanks👍
Strange why needs a mod to fix leak issue. Is it posted in a service bulletin from factory to do mod or just a post on a forum?
Thank you Mr. Carlson! I maybe missed something. There are many sockets on this tester. How did you know which socket to use to place your probes into, 2 & 5, 0D3.
The 0D3 datasheets are available online and in tube data books. The datasheets show the location and purpose of the pins. Looking at the top of the tester, the pinout is mirrored from the datasheets.
It's kind of amazing that the guy that did all the work on that fairly recently didn't notice that cut wire..
I mean it really stuck out like a sore thumb....
Another top notch video by the best of the best trainer on you tube #1 thanks Paul I love you channel
Thanks for your kind comment Mike!
I’m sure that engineers with 40+ years of experience at NASA get excited when you release a new video.
I'm guessing that the grid lead was put there for tubes that would have the grid come out to a separate pin, like a 304TL. However, somewhere along the way, someone probably decided that they wouldn't have the need to test a 304TL, and thus put that tape over the grid lead. (Don't know why, but they probably should have probably removed the grid lead if it wasn't going to be used.)
These are great testers! Where would you insert a plate current meter for matching power tubes for draw?
Paul, I didn’t understand why you installed the capacitor for positions 2,3, & 4 of the leakage sensing? And, why that value of cap?
Hi Jim, There is ripple from the loomed wires, "ETC" getting into the meter circuit, the 4.7uF value is just enough to filter it. Since the leakage circuit is DC, it does not affect the measurement as shown. Someone else mentioned (in the comments here) that in their future models, they must have noticed this, and added a value to do the same thing. So it appears to be a possible design flaw that was overlooked. Not enough coffee that morning I guess :^)
Did North-Americans finally recognize the brightness of Mr. Siemens and call the micromhos micro-Siemens? :)
I was about to make a very similar comment. North-Americans have been very resistant to SI-units for a long time.
The former owner was most likely a pilot, who installed the lights to comply with ICAO regulations where Red is on the left and Green is on the right. That's because Red is for port wine. Port is on the left side and it is always left at home before flying. Green is on the right because Green is for the Irish and everyone knows the Irish are always right 🙂
Now that is just plane funny!
OK.. that flew over my head..
Can you touch base on how to use more modern equipment like Tektronix 577 to match 6CQ7 or 12AX7 type of common audio tubes?
Mr. Carlson I love watching your channel. I've learned so much. One quick question ❓ if you would answer it for me, Can I use high voltage ⚡⚡ microwave diodes for a full bridge rectifier? 🤔⚡☠️
Great and honest review sir you are awesome Mr carlson's sir😊 thanks for sharing❤
My pleasure!
Has Mr Carslon seen the episode of Skippy the kangaroo defusing the H-bomb?
These Westons 981 type IIIs are a whole lot like the Heathkit TT1s. I have a Triplett 3444 that reads in actual Siemens, or micromhos. Was that genuine purple mimeograph? I have a few tube testers, and I have somehow managed to NOT bring any more of them home with me. That classroom Hickock was a hard one to pass up. It was something like a giant Hickock model 600, with an enormous meter face, and mechanically linked dual controls that could be worked from either the front or the side. It was also the size Las Vegas slot machine.
I had to go look. I have the rack mount Weston model 686 laboratory grade industrial tester with the flat table top test bay and the sloped top panel. That one is probably the best one I own. It is also a royal pain to set up though. It can put 400 volts on the anode, so it outclasses most testers, except for the fancy English Avos, German Ontras, Nuebergs, and some other $$$$ lab grade stuff.
@MrCarlsonLab,
I have a Moza Racing GS SIM steering wheel. One of the joysticks is defective. It does not actuate the X-Axis pot. Moza support is really tough to deal with. Even though it is under warranty, I would like to repair it myself. I cannot get the knobs off the rotary encoders. Moza had problems with them falling off, so they glued them on. I tried nylon/plastic prying tools, but they don't even move. I tried heat, with no luck. Do you have any tricks?
If Mr.Carlson can't help you, post this question over on Haseeb Electronics. He fixes a lot of random gadgets like this. I can't promise he can help you, but it's worth a shot. Wrap a piece of strong string like fishing line around the shaft under the knob and try pulling. If it still won't come off, heat with an electric heat gun. Be careful, a lot of plastics are VERY cheaply made so use your judgement!
@@W1RMD Thanks for the option, I will check it out...
Still waiting for more on the communication receivers you promised us a while back. I know you are busy, but I am interested in those types of radios. Please let us know when you will get back to those radios.
They are coming, they are just "Incredibly" time consuming. Each video is about a months work. You are the 5th person out of 370+ thousand subscribers that has asked.
Hi Paul. Great video as always, can’t wait to get a notification of a new video from you. Just a quick question on calibrating these old machines. Don’t they normally ask that we use a 20k impedance meter? Is your Fluke 20k ? I just want your opinion on this as I always freak out about not adding that 20 k resistor in parallel with the meter and then I redo the alignment .
Hiccok specified use of a 1K ohms per volt meter impedance for all tube testers alignment work (except grid signal measurement) And therefore if you were using a digital meter for aligning a Hickok you should put a 150K to 200 K resistor across the meter's probe leads. The grid signal however could be measured directly with a digital meter because Hickok specified a high-impedance VTVM for this.
The answer is quite simple, what is the input impedance of a grid circuit? It's a lot higher than 20K Ohms! If I was to load the grid circuit with a 20K resistor, I would have a big reduction in signal amplitude. The 6K6 is installed to load the rest of the tester, (not the point we are measuring.) You will notice in the brochures regarding this tester, the values for the GM multiplier are measured "Peak to Peak" which is done with an oscilloscope, or high impedance meter.
@@goodun2974 That’s correct. I remember this 1k/volt from when I calibrated my I-177 . Thanks for your input
@@MrCarlsonsLab Sorry, Imight have put my comment in the wrong time of your video. I wasn’t referring to the grid voltage measurements which indeed have to be taken with a high impedance meter. Thank you
W00T!
Bob Andersen's tube tester has a simpler layout than this one.
His uses a bank of toggle switches along the bottom and it comes with a book that lists the settings for each valve type.
The rollers are a better option.
Will this method work on the alignment of my Hickok 6000A also? Thanks
The Hickok circuit is quite different from the Weston circuit. Some of the basic techniques will be similar but that's about it. Most Hickok units have few if any calibration controls, so it's more a matter of verifying correct voltages and readings than of adjusting things. The Alan Douglas book "tube testers and classic electronic test equipment" has some useful information in there; and years ago I bought several reprinted Hickok service manuals from ebay. I would imagine you could find the information online if you keep looking.
Excellent as usual. Can you please go back to the Boatanchor Shootout soon?
Hi Tom. It is still on the list. Here's the thing: The amount of time it's takes to do that series is almost not worth the views I receive in return. Are others not interested in communications receivers anymore, or is UA-cam just not promoting?
Hey TD75, you place a lot of demands, but what do you offer me in return for the weeks of work it takes to make a video? Answer: NOTHING! Realize this when you make your comments here, and on other UA-cam channels. HEY! Did you read my other post on your other negative comment? Well if you didn't, here it is again:
Hey "TD75"... Your negativity didn't work! People here on this channel are intelligent, and don't play along. Do you know that you create your own history on UA-cam by the comments you leave. All the comments you seem to leave here are "negative." You know, when you do this, channel owners can "Shadow Ban" you from their channels. That means: When you leave a comment, only you see what you have posted, but no one else does. If you have been banned on a channel, when you log out of your UA-cam account and look for your comments, you won't find them. Pretty tricky right! I haven't banned you yet, "Because I'm Tolerant," but if you keep leaving nasty and negative comments on my channel, you will be banned. This also helps UA-cam realize that they may need to put your future comments (on other channels) in a review folder, so then channel owners (like myself) will then have to manually "OK" your messages for them to show in the comments section. Again, only you will see your comments until your messages get an "OK" from the channel owner, and released manually from the review folder. Are you wondering how many channels have done this to you now?
Now do you want to Unsub, or should I help you with that?
What determined the value and type of capacitor that you used for the modification? Why 4.7 and poly?
Poly = low leakage (Its placed in a leakage circuit) 4.7uF = just enough filtering to settle the needle in all positions of the leakage function. So... Not enough capacitance to slow the meter appreciably, not too little as to still show a false needle deflection issue.
Thank you for reply. So how did you determine the value 4.7 was it by math calculation or trial and error or is it just something you knew from experience?@@MrCarlsonsLab
Make sure to remove the foil before energizing!
Extremely disappointed there wasn't a Thunderbirds joke at 23 minutes in.
Grease?
Is this the tester the Heathkit TT-1 was based off of?
Yes!!
HEATHKIT did do some re-engineering on the Bias Oscillator. You. n compare schematics to see the differences in design!
I have a Sylvania 220 tester. It came with that "old electronic funk smell" free of charge. Heh, "charge". Does anyone have any idea regarding how to get rid of the old electronic funky mildew smell? I've tried leaving it open and airing it out for a few days to no avail.
But why add a cap, to solve an in- circuit problem, that wasn't in the original schematic?
It was overlooked at the time. Engineers need lot's of coffee so this doesn't happen :^)
Can an Eico 666 meter be repaired? I had a friend use my tester and they had the wrong settings for a tube and I think it cooked the meter.
It depends whats wrong, and how it cooked. Most meters can be fixed, it's a bit like watch work, but it can be done. I have fixed so many, I lost count years ago. You would want a small microscope, some SM tweezers ETC.
@@MrCarlsonsLab I am blind, so I’m afraid that repairing the meter myself would not be an option, do you repair such things for customers?
You get the chance do a video on the Cobra 2000 gtl especially if Dr bill who a ham work on it he did a mod for the recive made it even better some call him Bill Good ham radio or CB he made lot of money doing it
Hey Paul, what are your thoughts on the Triplett 3444? Opinions seem to be either "the greatest tube tester ever made" or "overhyped piece of junk". I was wondering what the master's thoughts were.
Altyazi yoktu pek nisey anlamadim altyazi lutfen
Strano,sono italiano e nel 95 % dei casi i sottotitoli su questo canale sono presenti per decine di linguaggi diversi.
I am very sorry mr. carlson, I learned so much from you and tried to support you in many ways, here or on patreon. But youtube is forcing me out of the platform by trying to force me to watch their retarded quantity of ads( litterally more ads than video time). So I am leaving this platform. I will stop by your patreon from time to time. thank you for everything that you do, I was able to start my own repair business in no small part thanks to you. Live long ! Maybe one day we will meet again on a better platform.
I have one of these and what can I say but junk. It doesn't work. I have recapped it and still nothing and without a service manual it's a waste of my time. I have done a lot of research on it and to say its nightmare is understatement
Junk? One of the best tube testers out there is "Junk?" Ok then.
@@MrCarlsonsLab I know it should be one of the best but unfortunately my tube tester is dead to the world. I found the problem to be in the transformer is open.
@@carl112466, I feel your pain, but ---- didn't you use a voltmeter to verify AC voltages going into and coming out of the transformer before you continued on and recapped the unit? Checking for power supply primary and secondary voltages from the transformer is electronics 101. In the case of a tube tester the other most important thing is to verify that the meter still has continuity. If the transformer and/or meter are bad then it's probably not worth restoring except perhaps for the most dedicated and experienced electronics tech; and even then you may need to have 2 of the same model so you can borrow parts from one to fix the other. It's a bit like owning an old British sports car.....
watched this whole video and you didnt even test some tubes
Did I not test the 6K6 before the Gm alignment? Did you really watch the whole video?
I have a salvaged B& K 747. SHOULD I FIX IT ? WHAT DO YOU THINK ?