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- Опубліковано 3 жов 2024
- Dave repairs a classic Tektronix 400MHz 2465B oscilloscope that's been sitting on the mailbag shelf for years.
Arguably the greatest analog oscilloscope ever made.
BONUS magic smoke escape!
Although it was repaired to a functional level, this is kinda Part 1, as not all functions were exercised and tested, and not all parts were refurbished.
Service Manual: download.tek.c...
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#Tektronix #2465B #Repair
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Why do capacitors have the negative marked and boards have the positive marked? Seems like this sort of problem could be reduced if they agreed on one or the other.
Worse is when the silkscreen doesn't have + but a filled in section of the circle, and sometimes that's positive and other times negative!
My first guess is just to be consistent. Old caps used to label + and - (as I recall from decades ago). Diodes have stripes.
Agreed. Another hint, lots of equipment I've worked on with radial caps have a square pad for the positive terminal and a round pad for the negative.
@@gregfeneis609 Classic HP gear dating back many years does this.
Don't even get me started on tantalums being positive marked
Hi Dave. That would be me who sent you those scopes. You and Sagan unboxed in a mailbag, Episode #695, roughly 4.5 years ago. So glad you got one to work. Turned out to be just the right amount of failure for a good troubleshooting video - not too easy, and not BER.
Neat!
Perhaps Dave hasn't seen your comment, but thanks for supplying the old units to Dave and his non-restorative trouble testing.
Thank you!
Oh, cool, a new ElectroBOOM video!
Exactly what I was thinking LMAO
😂
Always measure the ripple on the rails, don't rely on indicated voltage, very valuable lesson Dave.
On the other hand, TTL is VERY forgiving of ripple on the 5 volt rail. TTL can easily tolerate up to 1 volt peak to peak as long as the max positive value stays under 5.5 volts.
The old HAWK fire control control computer (circa 1975) used an unregulated 5 volt CPU power supply. 1/2 volt RMS ripple was not unusual.
On the other hand, CMOS logic is very tolerant of noisy Switching power supplies, but very sensitive to low frequency ripple on the rails. Nature of the beast.
I used to work for HP. Love seeing the Keysight scope fixing the Tek scope!
Love these repair videos. Do more Dave. Doesn't even need the exploding cap to be good!!
Do more Dave! Do more Dave! Do more Dave!
"Easily the best analog scope ever made"
eBay prices have now tripled.
Ebay prices were already insane on this model, it's highly sort after.
EEVblog , *highly sought after.
theR6969 breathe mate
@@theR6969 That's just his Aussie accent.
I remember these from my university days like 10 years ago. No doubt there are still schools which have these in theyr inventory, and you can get them cheap that way.
I have the 2467B and want to say that this video demonstrating your troubleshooting has been very helpful for me in the event that my ‘scope gives trouble. Thanks! 👍
That capacitor went all PUNK ROCKER on that PCB!!! Love your channel Dave! This is what makes electronics so much fun! Failure is learning! Fearless is earning!
Great video! I picked up a 2467B at an auction about six years ago, and I love it. It’s my goto scope, so I was bummed when Dave said the 2465B was considered the best. “Doh! Missed it by this much!” But, then he made his comment at the end. Now I can avoid years of counseling and hold my head high again.
Just got my hands on a "parts only" 2465, exactly like the older model here. This helped me at least confirm all major bits are here (and some shouldn't be black lol), thank you very much!
I always love a good old school repair vid!
The video of your chat with Dr. Marshall was really super awesome! Very much *YES!* I loved it!
Wrong video to comment )
I’ve got a 2465B in blue, in pristine condition and i love every single MHz of the 400 inside.
❤
Continue to restore it...Best analog scope you'll ever own. I use mine constantly!
Love the 2465B, and Tek scopes in general, recapped mine a year ago. You must restore it, you know you want to... :)
As for the browning of the PCB, those components should have been placed at least 5mm off the board from the factory to prevent exactly what was shown. The power transistor should have been mounted onto a small heatsink... Great presentation once again Dave, well done... 10/10
Wouldn't be a bad idea to throw a heatsink on it now to keep the charring from getting worse. At least the board's not punky yet. I've seen boards where the resin is almost completely baked out and the traces are floating in mid-air.
"It went through the power-on self-test!"
**BANG!**
Eh, good enough. Ship it.
the fact that you have so many videos is great. I do work (programming) and while I hear (and sneak peak) your videos. Some thought are super interesting and I rewatch them with more attention.
When measuring using the trace, you're supposed to measure from the middle of the trace, not the top of the fuzzy edge. I'm an old metrology tech who has repaired and calibrated at least a hundred of those scopes. For instance, when you place the trace on the center graticle (to reference it to ground), you're placing that graticle in the middle of the trace. If there is noise on a signal, it may thicken the trace. Not to mention, the trace thickness can change depending on the brightness and focus.
For a least three years that I watch your video #695, I waited for this video. There are only a few videos about fixing the Tek2465b scopes and with an explanation. I hope you can dedicate another "part two" video explaining how to calibrate this scope and also discussing if it is necessary to do a mod adding a heatsink for the U800 IC. I have my tek2465b working and I will do a recap and I would like to know more about the calibration procedure. Thank you so much for this video Dave!
A perfect instructional video for me. It is so helpful to hear the thoughts of a technician as they encounter problems and how they trace things down. Thank you so much.
Electroboom at 27:37! Lol
Lots of fun, having the cap blow was pretty amusing! Definitely would like to see a part 2.
All thumbs up for not cutting out the PEBCAO.
I would replace those two resistors near the transistor, make the replacements stand on their legs a good 10mm off the board.
Also lift the resistor and stick a heatsink on it, before the board burns enough to become conductive. Check if it is already and cut some slots if necessary.
The 2465B is missing the blue CRT filter. Slide it up to remove it from the bezel. This one also has the leaky SMD electro's on the control board, with the attendant damage in the area from the electrolyte.
Those SMD caps are gnarly on this one. Mine had this a little bit on that board (mine being a 2467B) but same power supply cap issue. Mine all puked however.
Wilson!!! Hahaaaa .. I love my 2465BDM. If I had a case I'd send it to you.
Is that an Outcast reference ?
@@amciaapple1654 he cracked me up! Yes, the cap. 28:20
Ah yes, I remember the good old times of that random cap you put backwards, truly exciting times lol.
Incredible to be at the bench with a Master... novice here and I'm learning so much!
Yup i own one had to service it once as the X Y caps failed and the spark gap arrestor had got tired but still on my bench and works to this day. You can really magnify your signals on this scope without any lag what so ever. Analogue scopes are a must however that does not mean they are better or worse than a digital scope, they both have their place on the bench.
Hi Dave,
Be sure not to keep it turned on too long with an opened case as the non obtanium hybrids in this range of scopes are known to overheat as the airflow without casing is not as it should be! When servicing/repairing these scopes it is always best to have an external fan blow the heat away.
That is a lovely scope...I love Tektronix scopes....just can't afford them although in work I have used these beasts......Nice result Dave
Lol when that cap blew, so funny Dave. You make great videos thank you!
OMG take the LCD shipping protection film off the *121GW meter!* I think *you* can get a replacement if you happen to scratch it any way! ;-P - 10:53
@Blondie SL - Sure but I'm guessing that you aren't recording YT videos and have your own meter in production and thus can replace the screen plastic, case or even the whole meter for free or at very low cost. In the field is one thing but in Dave's lab there is no reason to leave it on.
@@ElmerFuddGun Do you leave the plastic on your car seats when you buy a new car?
Dave, you can Dremel into the power points of that Dallas chip and solder in wires to put an external battery in it. It's a lot easier than unsoldering that dang thing. Also gives the ability to put the battery somewhere safer for the far future when it leaks
Its always best to memory dump it first so you've got a backup copy before doing anything
@@DanafoxyVixen How do you do that? What reader and software would you need? I would be interested in learning that.
@@DanafoxyVixen Yes as Davey says, can you explain how to do this.
Daveyk021 Guess I’m very late, but:
There’s a diagnostic mode that you can access by pressing “volts cursor”, “time cursor” and “Trigger slope” at the same time. In that mode you use the “Trigger Mode” up and down to navigate between different tests, calibration routines and exercisers. Go to “EXER02”, press “Coupling up” once to run it, then you use “source up” again to go through the memory addresses. On the screen it displays two digits on the left, representing the address in hex, and four in the right, which are the data in that address. I’d suggest filming the screen while you go though all 256 locations
When i did a recap on hp 100mhz scope the trace lines cleaned up and where much sharper. Enjoy the video. Have some sheet metal bent for the case is what I would do and add a quiet fan .
Didi you recap all boards? I have a 2465A with a fuzzy readout. No so much, but I think it could have better focus
I acquired one for $100. There is a bad ground in it somewhere, a 'gremlin' of sorts, that moves every time I found it. A tap here & there, or on the table... Mine is a 2465, no letter. It's considered a Cadillac, and cost more than a new car back when it came out. They are the last of the analog scopes. My 2465 does flicker when I push a/b. The NVRAM can be tested by powering off, getting a coffee, play with something else, and turn it back on. If you see your display holding, it's working.
that cap is now modern art... truly a one of a kind
I love this beast :), it was presumably highest "rated" analog oscillosope :)
Hello Dave. Just at the end of the video you wrote the scope was without covers. It is very important to operate it with the covers in place, due to heat. It has an IC which works at 80+ DCV and it gets extremely hot without covers. BTW, excelent video (what a laugh with the cap explosion! X-). I have 2 of these (one like yours, and the other with integrated DMM), and both flickers the LEDs when you make any change in the controls, so seems to be normal. And, as always, thanks for sharing!.
At the Q1351 with the brown fiberglass - I'd put a small heatsink on it just to keep it a bit cooler. It's just an OCD type of thing - try to keep things cool.
Anyway - good job to wake it up from the dead. Sometimes an old unit comes in handy, now look at the next one!
Thanks for the video mate! many times after the board is flowed and cleaned, they don't clean the rosin core flux off after hand soldering. The rosin flux is inert after heated and It won't corrode as lang as a improper clean isn't attempted.
Great video. Funny to see the cap blows up. The known prank at university in the Lab. One time smart ass connected a electrolytic capacitor to a lab power supply, in reverse of course, turned the PS on and walked away. After a few minutes the cap blew up. Don't try this at home, as someone can lose his/her eyes. By the way, it wouldn't be a bad idea to wear goggles when working with this. I know I know, working with this stuff for 20-30 years and no accident, but .... Once, when I was a teenager, begin 90-ies I was working on DIY audio amplifier. The caps blew up almost in my face, and the small paper pieces fell like the snow from above. I will never forget that 😁 Gooch 30 years ago, feels like a century ago.....
27:35 that "WOW! WOW! FFFH! FFFH! WOW!" was gorgeous! :D
I would add a small heat sink to that transistor that is heating and browning the PCB. And maybe even add a small fan in that area since there seems to be quite a bit of heat there with the diodes, etc. Just a small PC 5V fan. You can get a low air flow and low noise fan pretty cheap.
The beautiful blue just jumped right at me when I saw the 2465 for the first time
Wow you know how this thing works in detail
If the 2465B ISN'T the best analog scoop ever, it's got to be in the top 5!!
I got it at the auction.
24012 YEN with shipping cost.
But! after received it !
It was a broken 2465BDV.
The symptoms are very similar.
I'm going to take a look at the same place.
Thank you very much.
It's good to see others put a cap in backwards every once in a while :)
Educational and I enjoyed watching this video. I subscribed immediately as soon as saw the electrolytic (polarized) cap exploded. Two main reasons that would cause a capacitor to susceptible explosion is Reverse polarity voltage and Over-voltage (exceeding the voltage as little as 1 - 1.5 volts could result in an explosion).👍
The _readout is fuzzy_ because you have it cranked all the way to the right. I don't know why you didn't stop turning the readout intensity when it was clear. It doesn't need to illuminate the whole room after all. - 34:57 ;-)
I'm sure that I read that the case is important with respect to the cooling of the ASICs, which I also understand are common failures (and are as common as rocking horse ***t). I have one of these scopes, an Ebay purchase of many years ago. I really must get it out and figure out what is wrong with it. So many thanks for this video.
Sweet repair! Such a simple cause too!
My array of 7000 series Tek scopes are pretty powerful. A R7844 400MHz dual beam with 2) 7B92A delaying time bases, a 7834 400MHz Multi Mode storage with 2) 7B92A delaying time bases, sharing a selection of vertical amplifiers, a curve tracer, a current probe, and assorted digital function plug ins. Might mention also a pair of 7804A 200MHz mainframes.. and a 2247A 100MHz portable with 500MHz digital co processor that does setup memories, rise and fall time, frequency & period, and other waveform analytics. A 575 and 2) 576 curve traces round out the Tek scopes. Feeling out of place is a new Siglent 2202s-x 200MHz- 2MS/Sec. I'll save the Tek TM500 and 5000, and the HP for another time. Just saying, these portables you have were pretty good, but I don't believe they were the 'best ever'.. others might argue the 7000 series and 11000 series might be the peak of their art. Reducing the ink load on the PCB reduced the dielectric absorption on the boards, improving HF performance. They even dealt with humidity during board lamination as quality factor. In house, degradation in the board lams was called 'Hook'. Tek even made an in-house only TM500 plug in dielectric analyzer for board QC.
Useful and nice video 👍
Your channel recommendations are exactly out of my platter! And yes, This Old Tony IS hilarious!
I’d add in another huge one: check in on Adam Savage’s One day builds! As the rest of his tested channel is very good as well, the one day builds of him in his cave are really great! He has an awesome shop and mixes machining, woodworking, prop making and a bunch of stories from his illustrious past at industrial light and magic and presents all of this with a infectious (no pun intended, coroni) passion!
Thanks for your videos as well! Looking forward to your next ultimate workbench!
Love this! More! Thanks Dave.
27:00 never celebrate too early😂
Went back to rewatch, jumped both times.
Goodnight. I was watching their very interesting videos. I have a tektronix 7603 and plug in 7L12 spectrum analyzer. It is a gift but it does not work. I took care of the repair by the low power source having all the voltages that the service manual tek 7603 says.
Did a cap backwards in a power supply myself once - with a similar result.
I have 2 of the original 2465 300 Mhz and they are truly awesome machines. I recapped both units 4 years ago when I rescued them from eBay and have received flawless performance from them ever since. They are a bit of a trick to work on but they are the Lamborghini of oscilloscopes in their day. I save all the Tektronix gear I can. I love the stuff. I liked the Bobbie dazzler it reminded me of the troll dolls of the 70's.
I am fortunate to own one of these fine refurbished scopes. It is a blast to operate. Dave, maybe you should make a case in a "Steam Punk" theme for this fine analog scope. Maybe you could add some funky pressue gauges on the outside just to confuse the visitors, lol.
"Some say... they're the best analog oscilloscopes... IN THE WORLD."
That sounds a lot more cool than just talking about cars with huge engines.
I waited since yesterday for this!
When I started to watch this video, I guessed something was going to go boom.
Saw the clip of the cap "Snapping" earlier.....
Dave the blue screen is an interchangable part. You can swap them!
I suspected it might be, will try and swap it.
EEVblog nope fix it lol
@@EEVblog You can swap them very easy. You don't need to unscrew anything. Just flex it a little bit from the front with a screwdriver and it should come loose. It's some kind of acrylic glass in front of the screen.
Nice going Dave! You just did a Bruce!
Tomorrow we will have a refresher course on component markings and placement...lol
Poor Wilson!
Dave you are great and the video is the best I seen all weekend... Lights flashing, bangs, pops and Smoke.. What more can ya ask for.... :D
Hey, I resemble that name calling.
@@brucejones2354 Yep! That's for sure and... Lol
I repaired also my 2445b some time ago, and still works :-)
I think I got more of a fright that you did Dave. "Woah!!!" :-D
Tek scopes or this era usually came with a full service manual including a schematic. I worked for a university in the UK for nearly 10 years servicing instrumentation including just about every Tek analogue scope. Bet you can find a manual on ebay...
We had an IBM 1414 IO Synchronizer on an IBM 1410 computer with a bunch of caps that plugged into wire wrap that had a whole bunch backwards. It worked that way for over a decade, but caused a problem with the printer until the machine warmed up.
dremel the NVram epoxy pop the old battery out and if you're careful you can stick a CR2032 holder in there. I've done that to a old compaq 286 laptop so it would boot after running the utilities disk on it.
Even though most of the changed caps are probably ok, we still like to see how the ESR held up after 30 years.
Repair = replace the broken parts.
Refurbish = replace all the parts at or near EOL (all the electrolytic caps, possibly some or all of the power transistors, the battery-backed SRAM, etc).
Since the video says "REPAIR" it would be a bit silly to complain about it not being a refurbishment.
The benefit of refurbishing something like this (as Dave mentions) is that it's old enough one should expect all the electrolytics to be near failure. It's cheaper to fix everything in one go than to pay shipping costs multiple times, spend time disassembling the device multiple times, etc.
I'd LOVE to see you get an old vacuum tube oscilliscope on the EEVBlog bench and take a squiz at restoring it to fully operational status!
I would also like to see that. I have an OLD 585A that needs a little work. Just need to find the time.
dave: it went through its power on self test! WOHOOOOO!!!
magic smoke: fuck you dear boy! *BANG*
Hi from BC.
Well sir you made my day that was funny but great vid.
Keep them coming.
great David you are fantastic , even when you are wrong !!!!
An oiled wooden case would really show off that vintage Teck scope. :3
Dan Lott Woodgrain!
Great classic oscilloscope...i've got a 2430A model.
Gota love them x2 class caps when they explode! All sorts of fun.
3:14, Up top, example of early board design for automated through hole assembly. Everything nicely orthogonal (this wasn't as important back in the hand stuffed days). Typical of US designs, or designs optimized to run on US equipment, you see all the axial parts in one direction if possible, because there would be a significant delay to change from X direction to Y direction and perhaps back to X and so on. Also, as shown, they tended to use same lead center distance from one component to the next, even when it wasn't necessary (they could have saved some space) because there would be a slight delay every time the lead center distance of the assembly machine was changed. The delays made for increased cycle time from one board to the next.
Hi Dave. With your insightfull recommandation about Rifa caps, I've just repaired a 38 years old Casiotone synthetiser. The 0.022 µF across the mains input was cracked, so I replaced it before magic deadly smoke. Thank you Dave.
Oh haha, now that I see what you wrote I’m making the connection. I was literally thinking he was calling them “reefer caps” as some kind of joke! LOL
My old Tek scope's tube finally gave up the ghost 😒 ... Served me well for a decade or more.
Now the arduous hunt for a brand new second handie.
You should be able to find new old stock on ebay. They show up from time to time. Old scopes are the best.
@@BobWiersema absolutely!
I'm going to try to find a newer one though, take the opportunity to upgrade as my current scope's bandwidth is only 20Mhz.
You're bang on though, there are hundreds of CRT tubes on eBay. 👍
Love my 2465B’s. Please do a full refurb, put it through a full test/characterization and lets have your verdict. Build something around it first as it needs airflow to keep cool
Bloody good video Dave :)
Love it! Good looking
Hi Dave.
I am a great fan of you living in Greece.
Great work you do mate.
Keep up.
I have not finnished watching the video yet and I noticed that on 6:38 the moment you push the power button a spark seems to flash in the mains capacitor area (upper part of the screen in mid to right). This happened twice. So maybe there is a possible problem. Cheers mate.
I am looking forward to a full restore including calibration! Note to self: don't use big ass Audeze headphones on high volume when Dave explodes some caps! I jumped about a metre up in the air!
Let the repair continue...
The Tektronix 485 was by far the best analogue scope. The 2465 never came close in terms of trigger accuracy and screen sensitivity. Also the rise time of the 485 was better.
I repaired a 485 because the trigger was malfunctional because the tunnel diode died. Unfortunately, the selected very fast (65 ps) tunnel diodes were unavailable for me so that I used one from my stock which is about 100 ps fast. The effect was evident - the trigger is less sharp now.
I would disagree. I have used both the 485 and the 2465B to maintain Army air defense radars. For sheer usability, you cannot beat the 2465.
@@johnc8910 I agree, the 485 is old style concerning usage. But the technical quality of the amplifiers, the display, and the trigger accuracy of the 485 is unbeaten. You realize this while observing seldom and fast signals in nuclear science experiments.
I also believe this series was the best scopes, at least for non-modular scopes). Bandwidth was adequate for most purposes, and their control layout was so logical.even though they were rated to 300 MHz, most 2465s could reach the same 350Frequency as the 2465a. They also triggered really well, and rock solid stable.
Only criticism was that they had a tendency to run hot. If Tek had put in better fans, used more heat sinks, or worked out airflow better, these scopes would be beyond any reasonable criticism.
They have gotten very expensive on the used market. Obviously not the scope's fault, but an issue for anybody wanting one.
2467 really isn't a better scope. The micro-channel plate tube has a fairly short life, and there are nit many spares around(there were never a lot of 2467s built in the first place). If you need persistence, it is easier and cheaper to use a digital scope.
The 2465B IS the best analog scope in the world.
Nothing to discuss or argue about it :-P
Those are real nice scopes, if I had one, I would use it all the time. As far as your question at 39:47, there are a lot of your viewers that have 3d printers and you could model up a feasible similarity to the original and have someone make it from a 3d printer. Granted, it would probably need to be made in sections, but you could screw the sections on and act like it was original.
that was a very satisfying pop.
Definitely! I hope next video.
HI DAVE
FOUND YOUR VIDEO VERY INSTRUCTIVE.
It happens that I bought a similar one with red graticule some 3 years ago but never used it until yesterday.
Checked the input voltage set switch to 230v. checked the fuse 2A. Plugged it in and switched it on. everything went fine. Got a nice clean and clear trace and as I was fiddling with the focus knob, I heard a noise and smoke started coming out from the back end, I switched it off and removed the plug.
I then started opening it up to find out what got burnt. It turned out to be a bridge rectifier, a 0.068uF capacitor and a resistor next to it. So then I went on UA-cam to start looking for videos showing these kind of problems and hot to fix them.
Having watched your video, I will give it a try , it is just a matter of where to buy the genuine replacement parts. Maybe you can help by giving the contacts of potential suppliers. I live in Mauritius, a small island lost somewhere in the middle of the Indian ocean. Thanks for reading me.
Still got my trusty Tektronix 2213A scope which I use all the time.