Tektronix 2225 Oscilloscope Teardown and Calibration - EEVblog

[@321reh]

Thank You Dave!! Nice Explanation!! I learnt a lot from this video!! Please ignore all negative comments!!! I`m a Electronics Engineering Technologist and Electronics Technician by trade and understood this video perfectly.. I think it`s hilarious that some individuals don`t find it important to have your scope properly calibrated!! And YES there are more problems in scopes or tv`s than just High Voltage Problems!!! I should know I repaired both!!! Your Video was the best 32 min I spent !!!

[@PhilipLeitch]

10 years later and this is still useful

[@ki4dbk]

Dave, you are like the Croc Hunter of electronics! That's a compliment too, since I also loved Steve Erwin, and love animals as well as physics and the technical sciences. It's good to see someone passionate and excited about their work and play. You have to have humanity in there, since that's who we are! Keep it up!

[@AC6000]

Thanks for the video Dave, you have inspired me to break out the service manual on my 2225 and perform some needed adjustments. My 2225 also has a large 1.5M (2W?) resistor soldered to the bottom of the board as R266.

[@RandyLott]

I love that old school layout. It's before my time, but I appreciate the hell out of the build quality! That bottom silkscreen system is absolutely beautiful. I haven't seen that before.

[@stringlesswonder]

I recently bought one of these 2225's as my first scope. Dave's 2 videos on this scope, and the availability of the factory service manual were a major factor. I got a good unit at a good price, but it does need the Ch2 Vert and Coarse Horz pots to be replaced. Not a big deal really as I found the parts I need reasonably priced, but having Dave's 2 videos and the manuals gave me the confidence I could do low level maintenance work to get or keep mine going. Thank's Dave!

[@konohh]

Same with me. With Daves videos on this 2225 in mind, I also recently bought a 2225 on ebay for quite a reasonable price. Lucky me, everything on mine is spot on and in calibration, just a broken power LED wanted to be replaced.

[@LZ1SSA]

Дейв, Поздрави от България. Голяма работа си.

[@TropicalEncounter]

The world needs more videos like this. Thanks Dave!

[@321reh]

The Layout is absolutely amazing!!! Incredible Job here....unit was made around 1986--1987......Glad I bought one of these!!!

[@321reh]

I learned So much about My 2225 without taking it apart!! Now with this video I am equipped to maintain My 2225 ( with my Service Manual ) Thanks Dave!! Once again you have proved to me you are a very good at what you know!!!

[@dmjita]

Dave thank you to make this great job for us every time. Many thanks

[@pb7379-j2k]

I just bought a 2225 for C-64 testing based on your exuberant other video on it! It will be my first “modern” scope, previously only having a 60’s Heathkit! Thanks!

[@Rebelgium]

I love these kind of videos the most Dave!

[@cam70ds]

I love this scope. I used to carry one as an FE in the late 80's. Had to hand carry it on the airplane. You could not do that today. Thanks!

[@danielhildebrand6892]

Love the Video! Such passion and enthusiasm! Just got a 2215 today and looking for videos and found yours! Cheers Mate!

[@mandelkubb47]

I just got my hands on an old 2225, and this helped a lot on calibrating it. Thanks a bunch, mate!

[@EEVblog]

@ae4se You still have NOT explained why the vertical adjust control SHOULD be on the main board under the CRT, in the last place I, and I think most people (who do not service these things regularly) would look. Please enlighten us with your brilliant technical explanation...

[@2M0JAS]

My tongue angle was all wrong, been struggling for years and now you've helped me fix it! ;-)

[@charlesdownen4071]

Thanks!

[@chuckjohnson9295]

I have repaired a lot of circuit boards in my life and I will have to say that silk screen on the bottom is fantastic. I am not sure I have ever seen that before.

[@richsavory7784]

The spring against the CRT from the frame is not there to prevent any kind of physical damage. It is the grounding spring that connects the dag (The conductive gray-black coating on the outside of the CRT) to ground. If you don't do this, you end up with 7 KV on the dag. The scope in the video was built in '91. The dates are right in front of your face... look at the ICs, they have 4 digit numbers such as "9112" etc. where 91 = year and the 12 = the week of the year.

[@EEVblog]

@ae4se Are you saying it's obvious that the vertical gain control would be on the main board under the CRT instead of on the vertical amp board?, and that I (not an experienced Tek service tech) am an idiot for looking their last? Please explain. And as you seem to know, please explain to us why the vertical adjust control is on the main board under the CRT instead of on the vertical amp board...

[@syncmaster710n14]

Oh you just can't beat the oldies, i have a Hameg scope that i believe was made in the early 80s, and i still use it over a digital scope. I just love the simplicity, no firmware, no usb connector, just a basic BNC and lots of buttons and knobs.

[@145psg]

Awesome. The energy you bring to your videos is just great!

[@techgood]

Thank you for all of your videos Dave

[@peterhaan9068]

Dave - Interesting and instructive video. Just a suggestion here. First of all you should always verify/adjust the regulated power supply voltages before you start randomly tweaking! I would be willing to bet that just one adjustment, back to mfr's spec, of one of the regulated power supply voltages would have brought your scope back into cal.

[@EEVblog]

@TheElectricnoob My video editor VideoStudio can autogenerate music based on length and allows me to tweak the settings. It's a third party add-on, so probably used in other video programs too.

[@sausage5849]

Nice one Dave. The tongue eyed thing, I think, is just a natural expression when doing these types of things that we all unconsciously do :-)

[@UberAlphaSirus]

Cheers Dave, You have cost me a fortune over the last year, but now I can regain some of my old stuff too. Gonna cal my really really old Analog scope with the Rigols (DS1052E you made me buy) probe cal point. Only because you haven't made me buy a fuct gen yet!

[@321reh]

I can't believe some of the negative comments being expressed in this video!! Dave is explaining the 2225 in a Engineering perspective and in my opinion did a damn good job doing it!! I am Extremely impressed with your explanation( I own a 2225) Am I a Technician,,,,,Nope !! I`m a Electronic Engineering Technologist and ran a VCR repair for 14 years,,so I was a technician and a Engineer!!! Most Technicians can calibrate there scopes with the help of a service manual and a little know how!!!

[@CodfishCatfish]

Great vids as ever Dave and in the very first few minutes you named a bodged resistor. If you look back over the video at 11:32 you see the exact same type of resistor in the middle of the shot so it looks like a Tectronix fix or update. It's seems doubtful that someone would have replaced both the parts but could be an upgrade.?? Your the expert I am only going by the video. 73 all the best

[@jdbhills]

Just bought one off ebay it has the 'bodge' resistor also, looks like factory install.

[@mohalothman99]

Lol Dave your technique what you mentioned at the end of the video works with me pretty well Super duper technique fantastic!

[@MedicineForFuel]

Awesome video Dave! Thanks for the "pro tip" about the tounge angle. Lol! Keep it up!

[@Leopoldino2020]

I had such an oscilloscope. A magnificent device. It's like a Mercedes or a Bentley!!!

[@TeroPihlaja]

Brilliant timing. Just watched the review half an hour ago! ;)

[@danmcbmusic]

great video blog, and great scope too. Nothing like a really good Tek analogue scope! I used to cal scopes and other stuff in the military back in the day. Good tip on the tongue! I'll keep mine in my cheek ... ;-)

[@thewii552]

YAAYY! I have been waiting for this for very long. Thank you!

[@ElectronicsAustralia]

Really great explanation Dave! Love the detail you go to :-)

[@robertdrinkall8947]

I Bought a 2225 a few day's a go, great piece of kit, well pleased.

[@stevedoubleu99B]

I agree about the older mechanical controls which probably required as much design skill as the electronics themselves.

[@321reh]

This is a Awesome Video,,,,,,,,,,,As usual I learned a lot,,Thanks Dave!!! Keep Those Videos Coming.

[@EEVblog]

@omgitschrislol It ain't just the solder, but lead weight and associated smaller board space as well. I wouldn't like to guess at a number...

[@moenhowto4655]

My Tek 2225 came today very nice and the two blogs I have seen so far by Dave will help a lot, only trouble with that tongue angle and eye squint is drool and eye water opps burnt my board out. :-)

[@EEVblog]

@ae4se I don't get it. Was it unreasonable for me to expect the vertical gain adjust pot to be on the vertical board?

[@EEVblog]

@ivaneduardo747 I learned that the first few words in the KZbin title are indexed much higher in the rankings than later terms, so decided to swap. If people can't find my videos, they can't watch'em :)

[@warplanner8852]

Jeeee-zus, Davey! You like bodges? Try working on a Tek 485! They have bodged parts al over! All artfully done, of course, but shows that Tek did a lot of after-production engineering. And the 485's test points are a saving grace. (True with most Tek scopes. Fun to work on!)

[@Nerull101]

"USA! USA! USA!" God I love this blog.

[@Ivo--]

I think these scopes were made in the time Fluke worked together with Philips. Philips Test and Measurement was situated in my hometown at the time, and I have a few Fluke DEMO units made in Holland. Great stuff.

[@nickzambrano]

Just bought one on Ebay. Can't wait to try it out.

[@jesusedierhernandez1526]

i got another job,but thank you for the offer, a digital osciloscope and some multimeters,will,make me happy,but i will buy those thing on this year,no problem,and happy new year

[@luchenderieckx1463]

I just repaired a 2225 from a friend. There was just one of the connections between the input attenuator print and the main board broken which caused channel 2 to virtually not function and apart from the difficulty to reach this multi-wire cable the repair was fairly easy. One strange thing is that both vertical position controls are reversed. The left knob controls the position of the right channel 2 and vice versa. There does not seem anything wrong with the cabling from the front panel to the main board, so I guess this was like that from when this scope left the factory. Mayne they changed the PCB design afterwards...

[@m0gga]

Dave you are my hero, so funny. I love your witty style of presentation. Keep up the good work.

[@KB1UIF]

Good video as always Dave! The spring refered to in the video may be required to ground the outer metalic coating on the glass of the display tube to the chassis. Also often seen in TV sets. My mentors refered to it as "The Aquadag coating" Not really sure about the spelling.

[@TheAdambee7]

i still use my old 468s. old Tek scopes are good workhorses. great vid man.

[@EdEditz]

Ughhhh that's where I failed in my electronics exam. Wrong tongue angle! Ughhh such a pain in the backside ^______^

[@lineyt6987]

Dave, you are a legend. Thks mate.

[@ki4dbk]

I was surprised to see that long plastic push rod in use on the power switch. Very cool.

[@WillemExist]

My 2225 has the same "bodge" resistor.

[@gman76utube]

Hoi Dave, :o) Great walk thru as usual. USA....USA...USA. Ha! Got a few tips from your video - I've got to repair my Tek 2246 scope I bought from ebay yrs ago. Anyway, the move to SMD as you state allows smaller board and also smaller lighter chassis. To the others, I'll take a vintage tek over a rigol any day.

[@Royalbigness]

Hi Dave, Are you able to do a video on the 465B ? How to check calibration etc and a general tuition on how to use one, say in an Audio application ? I'm new to scopes and would like to adapt it as I build my knowledge on Amp repair. Thanks mate.

[@ProHumanRights]

I would like to use the 2225 to check outside foil on non polar capacitors and noise for power supply used for audio. Do I need a signal generator to amplify cap? How would it best be set up. Thanks for your help.

[@Gairlochan]

Mine has a bodge resistor just like yours. I bought it in Sydney, and it says Tektronix UK on the back, and 'Made in UK' inside where yours says Made in Holland. It's made in 1986 also. But it doesn't have the little yellow decoupling caps across the CA3102 chips, nor the trimcaps you point out on yours nearby. Yours might indeed be an afterthought, as you say.

[@singhpk99]

HV transformer. check power consumption. If it is running rather cool, less than 90 watts, Hv transformer may be blown. The unreg 15 volts goes to 21 volts as it has no load on it. It normally powers the HV inverter using the 2n3055 mounted on panel near the fan. The 2n3055 has Tektronix part number of course. The HV transformer can be had maybe for $20 from tucker surplus, if you are lucky.

[@undefined40]

Designed with maintenance in mind. ...that I am allowed to see such again in my old days.

[@samsonofdan]

Here's a story for you Dave. I acquired a Tek 2247A CRT scope a while back and there was no output on the screen, but it booted up fine. So I figured I'd take it apart and check the PSU. After taking it apart, the first thing I did was discharge the CRT anode and the caps on the PSU. Just when I thought I had her safe for handling, BAM, my pinky got a nice shock from a 200V cap (can't recall the capacitance). I've been zapped my 120 mains before, but this hurt tons worse. Still fixed it though.

[@eliasragi7472]

Excellent tutorial, thank you. May I also ask if and how can the handle be removed. Thank you.

[@rustyrebar9647]

15:00 - that trimmer capacitor is called a piston trimmer. Their parasitic resonance frequencies are much higher than most other trimmer caps,which is what you need in a high BW circuit.....

[@MrPaddy1000111]

Love the "Made in Holland" sticker covering the "Made in Taiwan" on the board! 14:25

[@jcobnl]

And all the Dutch go mad: "It's The Netherlands, not Holland!"

[@Mr.Not_Sure]

Epic!

[@dealio82]

Good job man . Hope more from you

[@EEVblog]

@TomCEvans Sounds like a factory mod then, thanks for the confirmation.

[@Satchmoeddie]

Imagine calibrating this stuff for a living? A cal cert is over $1200 now for the military lab stuff. My scopes are the antiques with universal joints and shafts leading to cavities in the back of the scope. One is 50 years old this year. I use it at a shop I moonlight at. My Tektronix was stolen at one of these shops.It is an old HP that was comparable to a Tektronix and I think they are only 20MHz. It has 50 or so very lovely Amperex select HP matched section ECC88 tubes in it!

[@Zwank36]

love ur tear downs

[@alanshields1638]

Great teardown Dave. I bought a 2230 for a song and re-furbished, works great. Incidentally does anybody now where to buy Tektronix Blue paint ( apart from the States)

[@michaelhawthorne8696]

I went through college using Gould and Hameg scopes, good for the course but that's all. I used a Tektronix sampling scope going down to Pico seconds at GEC and 4 1/2 digit Fluke multimeters. This is in the early eighties, imagine what the company would have paid for these items. Even now these wouldn't be cheap. I have a 2225 at work and its brother ( I can't remember the number) with digital storage, I have at home a Vellerman 60 MHz PC scope (Stop laughing, it does me LOL) I think scopes are the most useful equipment you can have aside from a quality multimeter. Great video Dave, The layout of the board shows Tektronix as up there with the best of them..... an engineers dream Keep them coming By the way, you have some nice test equipment there....drool...

[@jaryH3]

Why adjusting for the peaks, not center of the line? If you change the brightness, you'll get off a bit, won't you?

[@44209david]

you said Tektronix 3000 scope as your signal generation not Agilent but great video as usal Great stuff dave!

[@lebeyes]

I found some 50 ohm terminator resistors that are not very precise (51 ohms, 49 ohms). I guess this can influence the calibration? The terminator resistors are probably from old 10base2 networks that used coax network cables. Are terminators for signal generators and scopes better quality and precision?

[@bitrot42]

Thou didst not check voltages! :O Given that both channels were low by the same amount, and the horizontal was slightly off, I would have suspected one of the power rails would be out of spec... Nice video, though!

[@ki4dbk]

It sure was...I am about to check and see if he has a 2465A teardown...

[@mikeselectricstuff]

Try turning on the auto transcribe - hilarious!

[@garrydolley]

Excuse the noob questions, but why do you terminate the input with a 50 Ohm terminator instead of just running it straight into the channel input? Is it because the output of your generator is 50 Ohm and you don't want reflections? ...and, if you _didn't_ terminate it, what would be the consequence?

[@ernestb.2377]

Great, the tong angle, very important 😆

[@KB1UIF]

Dave, isn't that spring at the the top of the case to ground the dag on the tube? Also check the power rails before calibration !! normally part of the calibration process.

[@gillianseed4419]

looks like it was kept in a clean room

[@mcac-youtube]

Oh, here i have one, i'm from Brazil. The problem are the potentiometers on the front panel. Their track wear out, there is bad contact. Cleanning was useless. I think to try conductive paint to repair it, but i don't know if it will work.

[@EEVblog]

@Madmax23419 Are you the same vintage as the scope? :->

[@kaysonntag74]

@ 10:00 7kV are still boring.😉 My best experience was a 27kV discharge of the picture tube (capacity Anode -> GND ~2nF) of a large colour TV set, a few seconds after switching it off. It really went bang and felt as if I had been kicked by a horse. The right arm was partially numb and paralysed for a few minutes and even after a day or two I had a pain like a sore muscle. You never forget that when you have experienced it.⚡

[@Gameboygenius]

0:38 I see a link! Or at least a 0 ohm resistor. It's near the ribbon cable coming off from the panel board, component index ends with 52.

[@benjaminbadrakh4049]

The 2000 series scopes are meant to be cheap and affordable. But also for best measuring accuracy, obviously. Thus the lack of long control rods. They are also to be ease of repair and calibration.

[@CoolMusicToMyEars]

Looking at the components it looks to be made after 25th week 1991, spring is for grounding of outer CRT carbon spray coating, Frequency setting is 50KHz for scope set up frequency, Look at the old Tektronix TM500 series, TG501A, SG504, SG503, PG506A etc or more modern TM5000 series.

[@dr07828]

28:34.... Did he just say "Half a bee's dick"? ..... LOL... That's great!

[@thearhi]

Resistor on the back (04:30) - I have same one on my tek 2225 - so looks like factory thing

[@Pieh0]

0:29 NEVER play that music again, it makes me feel like i've just been at a week long management seminar on all the latest management buzz words.

[@Nexfero]

+Pieh0 hahaha so Im not the only one, I thought it sounded like background music for an old 90s instructional video

[@ovalwingnut]

Back for a 2nd suck of the sav.... thank YOU

[@WillemExist]

Love the decoupling cap over the ic. What do you mean "resistor over the inductor. Adding damping!

[@mantaz111]

New intro. Sweet! ;D

[@davids6679]

this an old video. but was hoping someone could help me. I have a 2225 and the trace focus is off! even though I can use the trace focus knob, I can not get the trace to become thin and sharp! anybody know which POT inside I turn to adjust this?

[@JohnFHendry]

Well as Dave said "know what you are doing" and I can only imagine how many "know enoughs" messed with some of these older used scopes to use or sell them.... and have not seen any I would call inexpensive looking. As a project one of these would be great but as practical tool going past 25 years old is pushing it without getting lucky IMO without parts availability and knowing exactly what you are doing. There are some serious high voltages inside to deal with.... and 100v on the main board exposed as well.

[@murnelbabineaux105]

I have the Tek 2225. Great O-Scope!!