Oscilloscope Hitachi V-212 two channels 20MHz 1990 test repair teardown (missing trigger)

[@jonathantouboul159]

Incredible, I just got a well-loved v-252 from a retiring science lab, I tested it and found no trigger, watched you video and spotted the SAME jumper missing, although it's a different scope and a different chip brand... I soldered a jumper in place and my trigger now works nicely! Thank you for documenting this, very helpful, saved me a headache!

[@TeardownOZ2CPU]

wow this is funny, none of those scope worked, EVER !! Glad it helped

[@HenryPlumb]

I've just acquired one off eBay from a working lab somewhere, scope working but no trigger, exactly the same jumper missing. Amazing so many of these seem to have been shipped with no working trigger and have lasted decades like that!

[@TeardownOZ2CPU]

it is one of those jaw dropping moments, i just did not see , when i made my video 1 year ago, i expected my scope to be unique.. but sadly NOT.. thanks for all your comments and support, I am super happy this video helped so many people fixing their scopes.

[@HenryPlumb]

@@TeardownOZ2CPU Thanks for the video! I've just soldered in that jumper but sadly still no trigger for me

[@TeardownOZ2CPU]

@@HenryPlumb oh bummer, maybe that chip with missing ground needs replacement ?

[@HenryPlumb]

@@TeardownOZ2CPU I've ordered a couple and will keep my fingers crossed

[@HenryPlumb]

@@TeardownOZ2CPU Changed that chip and I think it's all good! So the chip ground was missing and the chip was dead anyway

[@gcpete4495]

I just bought a used V212 for repair. dated June 1993, and sure enough that one was missing the jumper for the IC ground. new at this , so likely would not have notice it without your video. Thank you Thomas!

[@TeardownOZ2CPU]

Happy to be able to help

[@gcpete4495]

@@TeardownOZ2CPU Started to recap my V212. the parts list and the schematic call for a capacitor 16v10uf on PCB 620 at position C53, but there is no cap there, just two empty hole and a cap drawing. do i install one or leave it?

[@walliesdebeer9681]

I am in South Africa and also bought one of these brand new triggerless 30 year old scopes secondhand for the equivalent of 20 Euros. Guess what? no jumper is installed. I'm going to fix it tomorrow. You are my hero Thomas!

[@michaellundsrensen2292]

I bought such a scoop in 1980 and it worked fine then. I've had it sitting in the box since about 1990, so I wonder if it still works? Are there any capacitors that have become old, tired and leaking or can I expect it to work?

[@TeardownOZ2CPU]

i recommend to open and perform deep going visual inspection, check for leaked caps, if all is fine, take a soft paintbrush and compressed air, and clean it, then try it out, also check the trigger wire mentionened in this video, and see if your trigger works

[@michaellundsrensen2292]

@@TeardownOZ2CPU THANKS, Will do!

[@danielito8605]

when in low frequency mode and only when not measuring anything, my V-212's waveform is dotted, what could I do to fix this?

[@TeardownOZ2CPU]

CHOP MODE

[@robertdeptula5355]

Reporting missing jumper from Montreal, Canada. Problem fixed. Thank you! You would expect "high touch" from Hitachi, but nooo...

[@TeardownOZ2CPU]

wow thanks for your comment, this is most likely one of the most crasy finds, and reveal a total lack of final function testing, I find it also very interesting so many scopes still exist with this problem, how did you use this scope the last 30 years ? it should have a very bad trigger without this jumper

[@robertdeptula5355]

@@TeardownOZ2CPU I bought it about a year ago from a thrift store here in Montreal for 40 CAD. Used it in my YT chennel to tell the oscilloscope story: kzbin.info/www/bejne/g5m1f6Jsi9t3b7c

[@smilleur]

I just found two vc-6015s in a god damned dumpster at the college i work at and THEY LOOK BAND NEW IM SO EXCITED

[@TeardownOZ2CPU]

wow good score

[@smilleur]

Ill let you know what i find im beyond excited. Ive wanted a scope for the better part of a decade now

[@Animatronicsu]

I just bought an used Hitachi v-212, the trigger doesn't work so I looked inside, and guess what, jumper missing ... Thanks you so much for letting us know the solution

[@TeardownOZ2CPU]

Wow one more

[@tsjwang9045]

Same thing happened to me! I bought a used scope from ebay, working but no trigger. same missing jumper. this fix worked. there must have been some bad work instructions and lack of testing that led to a bunch of defective scopes being shipped

[@TeardownOZ2CPU]

WOW thanks a lot for that comment, it is very interesting to know mine was not the only one.

[@ebswift]

I just scored the same model Hitachi V-212 today, not yet powered on until I check it over, but the first thing I've discovered is the same missing bridge wire as others have also mentioned.

[@TeardownOZ2CPU]

wow another one with a trigger that NEVER worked,, amazing !! every time i hear from you, i feel this video is getting more and more important, just too bad i did not make it many years ago, could have helped many more.

[@ebswift]

@@TeardownOZ2CPU The funny thing is, from an engraving on it, this one originally came from an electrical trades training facility.

[@TeardownOZ2CPU]

@@ebswift maybe they only used XY mode ? or adjusted the timebade to show some free running curves, rarely used but some things you actually dont want the trigger 🙂maybe they used this scope for jobs like that.

[@ebswift]

@@TeardownOZ2CPU Well finally got it onto the lightbulb current limiter and it looked okay, so after detaching it from that fired it up and it's working just fine without that bridge wire in place. That IC's ground is reading as being lifted slightly and we were getting voltage readings of over 4V. Functionally it's fine so we decided not to break it down any more and left it as-is for now.

[@TeardownOZ2CPU]

@@ebswift wow amazing, that ic ground is floating and still your trigger works :-) also under all conditions ? if you find triggering is not working at slow or fast modes, please try to make that missing bridge, and see if solved, and post your results.

[@walmirbraga1162]

Eu tenho um dessa marca e modelo,e o trigger também não funciona,porem funcionava,vou ver se consigo com essas dicas faze- lo voltar a funcionar!! Thanks for shared!! Braga PY 4 PCJ

[@TeardownOZ2CPU]

thanks a lot for your comment, if your trigger is also not working, I would almost be very sure it is the same problem and same fix, please check and get back to us.

[@beakytwitch7905]

I think the Y driver transistors by design are somewhat overdriven, the better to push the bandwidth up. The CRT is single channel, and the "double beam" comes from chop and alt switching, and for that reason on its own we want high bandwidth.

[@juniorcomsono]

Hey thomas! What's the name of that tool you used to figure out the Diode and its values?

[@TeardownOZ2CPU]

if it is the tester at 13:49 you think about ? it is called Mtester it is also written on the LCD display, if you google this you find many cheap hits, I like it a lot it can measure almost all components very fast and easy to use

[@ryan8773]

is this model pretty ok for a beginner ? its going to be for audio amps

[@TeardownOZ2CPU]

yes it is super for alle audio range use, how much do you expect to pay for it ? let it run for a good while at the sellers place, and see it still run perfectly stable, bring a probe and use the cal signal

[@omarcusihuaman4261]

Its really hard to believe that jumper was missing 😱. I got a similar HItachi last week, it turns on but theres no signal.

[@turkalpkucur]

I think it is a good oscilloscope for beginners! thanks !

[@to1n_powere675]

Good job Man.

[@ebayscopeman]

One place I worked had dozens of these. They used them for years. Never saw one fail in 10 years. Yours must have been built on a Monday. Maybe they were just using it as a X-Y scope where trigger was not needed and the vertical failure is why you have it. Sam W3OHM

[@TeardownOZ2CPU]

yes that is right

[@TeardownOZ2CPU]

Hi sam, one more same fault now reported :-)

[@ebayscopeman]

@@TeardownOZ2CPU Hi Thomas, well now you know the first place to look! I have a GR1656 LCR bridge that was once owned by GM that had one decade that didn't work right. I took it apart and one of the rotary switches that had several decks in it had a bus wire that passed through several decks where the wire was never soldered on two of the decks. On one of the two it made physical contact and on the other one the wire passed dead center through the terminal hole, not making any contact! I still don't know how it passed GR's final checks. According what I read in GR's literature their instruments were built start to finish by one person. Quite a project. Can you imagine doing that in today's world or having to be the one that all you did was build the same thing over and over? Amazingly the 1656 (really a GR1650 with a precision decade upgrade) is a 0.1% instrument which is still respectable for L and C even by today's standards. Which proves once again that an instrument doesn't have to have a digital display to be accurate.

[@Mela_Pipi]

No flyback. Sinus topology.

[@ferhatazakl3385]

👍👍👍👍👍👍👍👍

[@Stuart_MM7SHX]

Mine is the same!

[@TeardownOZ2CPU]

WOW thanks for telling us,

[@Stuart_MM7SHX]

@@TeardownOZ2CPU Thank YOU for the video. The trigger on my scope is now working because of it.