#184

[@JCBudro16]

Excellent video. Glad I found it even nine years later. One thing that might be worth adding is that it's usually good to let the scope warm up for 20-30 minutes before performing the calibration.

[@chongli297]

Awesome video, thanks Alan! I gotta say, what a lovely scope that is. Nice sharp trace, very clean and organized controls, what a beauty!

[@Chicken_Massacre]

Nice! You gave me the courage to try to adjust my 44 year old 25MHz oscilloscope. The lines are beginning to oscillate in intensity and both X and Y axis amplitudes are off by 1cm. It was last calibrated in 30/01-85 and was due next 30/01-86 which is three months before i was born. Funny :)

[@964tractorboy]

Very clear and instructive as always. A process I'd never previously considered to be so involved, if indeed I considered it at all. Thank you.

[@thats2kewl]

Such a good (and useful) video...I really appreciate the way you explain the steps you take. Presentation is so clear and informative. Thanks so much!!

[@samba3403]

Finally a guy who talks electronics, grate set of videos that i have seen so far, keep up the good work.

[@BM-jy6cb]

W2aew - your content is top notch. I really don't understand why the KZbin algorithms constantly push celebrity court cases or how much can you eat challenges when this sort of subject matter is all I ever watch!

[@KX36]

I like this video, watching every adjustment come back in gives me the feeling that all is right with the world... :)

[@jonyheringer3150]

This video was a great class for those looking for such important technical information! Thank you very much for recording your work; because that helped me a lot. Be able to see; how to make. Simply amazing!

[@das250250]

Beautiful work , i didn't realise the steps were so many in a simple scope. Also , what a great educational process building such a scope would be .

[@stevescnc8155]

Great video, very knowledgeable and concise information. Helps understanding about calibration and adjustments that can be made.

[@Xanthyn]

Even though I have a different scope, this was a helpful intro to help me understand what I'm looking for when calibrating my own.

[@grahambambrook313]

Another great tutorial video, Alan. Many thanks, it gave me the confidence to attempt a rudimentary calibration on a Tek 7403N I just managed to resuscitate and save from the scrap yard!! :-)

[@olafwagner]

This is a brilliant video, thank you. I just purchased a GoldStar OS-7020 scope, and I will go through exactly this process (as soon as I can track down an elusive service manual)

[@gixerags750]

I have watched this over 20 times...such a brilliant informative how to Most 20 -25mhz CRT oscilloscopes look they are the Pintek chassis, I have seen, my Telinstruments, Sony, even the Hitachi V20, look the same, they all seem to havea common REAR panel , connectors The Heath 4552 service manual is easily available on the Web, unfortunately my Telinstruments TI5252 was not.

[@gixerags750]

Hi Alan, would there be any reason to or not to replace the Electrolytic capacitors before this calibration procedure,? It's just I plan on following this video and would like to replace caps while it open. Sorry to be a pain Cheers

[@paulmorrison1821]

Great instructional video - thanks so much for taking the time and sharing your knowledge.

[@pa4tim]

Nice information, like allways, with sound advise, brings me back to my first serious scope cal, a Tek 465. I got it right but it took a lot off time (like 15 hours or so) and I learned a lot from it, and for most that you first have to check if you understand every step and have all the gear needed. Missing one instrument can screw up the whole operation. I really learned that when I calibrated a 1ns pulse generator with a 150 MHz scope. It looked perfect until I got a 1GHz scope and had to do it all over again. You often need better testgear as the gear you are adjusting or repairing. Some tips for your viewers if you do not mind: Do not think to light about calibration and adjustments of test gear, it is very easy to make it (much) worse. A tip I learned long ago from an experienced meterologist, is to mark the settings of adjustable components before you adjust them, so that if you screw up, you can get it back to its old state. A picture will help too. What I sometimes do is making a few high res pictures and marking all adjustment points with their name/number and value and in more complex steps the number/paragraph that step has in the manual. That can speed up things a lot and forces you to read and understand every step in the process before you start. Do not do partial calibrations unless you really know what you are doing and not because you do not understand a step in the process. It is very easy to make it worse. Back then it was a hobby (it still is) . Nowadays I make my living from repairing test-instruments and calibration gear. I do no calibrations (not my idea of fun ;-) ) but depending on the work I did, I sometimes have to calibrate it, or at least check it after repair.

[@w2aew]

+pa4tim Good tips - thank you!

[@paultopolski6595]

Alan, Superb video as always. This is a perfect warm up for calibrating a couple of Heathkit scopes, an IO-4510 and IO-4550 as well as an Elenco 1325. All together, I spent $65 for the three of them a various ham fests. These scopes will be good practice because four Tek 7000 mainframes and about twenty plug-ins will follow. Thanks for the great work. Thanks, Paul, W1SEX

[@bobjacko5658]

Enjoyed your calibrate video and it pointed out how I do, indeed, have to find the instruction manual for my NRI model 2500 scope. Many of your other videos, however, are also helping me out to learn how to operate the scope.

[@brikaf6001]

Excellent

[@88merc300e]

Very good info. Why would anyone dislike this? Thanks Alan.

[@Wil_Bloodworth]

This is excellent! I wish I could find the equivalent calibration procedure for my Sencore SC3100. I'm not sure those instructions exist.

[@davecc0000]

Another great vid Alan. Many of have heard of cal'ing a scope; I for one didn't know how involved it was... Thanks!

[@billbates7810]

Really nice video, very well put together!

[@SIXSTRING63]

I have the same scope branded with the Elenco name. Came with my NRI home study course in the early 90’s. Still use it. Works great. Maybe I’ll go through it and touch it up a bit.

[@magdalenoarellano1841]

otro gran video de mister muy instructivo y motivacional muchas gracias

[@blaaaaaaarghable]

You forgot to mention maintaining the correct tongue angle when making adjustments :p

[@w2aew]

Oh, well that goes without saying! Why do you think you never really see me on camera!

[@dave-d]

There's a channel for that!

[@boonedockjourneyman7979]

The only person I know who has the angle problem has a whole ton more in other areas.

[@sbybill3271]

:)

[@vhm14u2c]

The 60mhz scope I just bought used is a bk precision 2160a, has almost identical controls on front panel, including component test on bottom row. Bk did not provide much for calibration in their manual. I have found that hk so-4552 manual with the specific adjustments you done. I’m not going to do any, but may check references from the manual if I find problems down the road. Thanks for sharing!

[@Valenorious]

Probably important to emphasize is that it needs time to warm up and settle before you make calibration adjustments. But that goes for use as well.

[@clems6989]

the first job I had on a bench, was equipped with one of these scopes. I realize they were rebranded under different names sometimes. But my goodness just Imagine how many of these scopes were sold to ametuers, hobbyist, schools etc. And how many good techs were self taught using these. Back in the day a 20 or 25 Mhz dual trace scope was the entry level scope, And extremely useful even to this day..I really enjoyed watching you calibrate this old girl...Sorta like watching someone do a tune up on a 57 Belair. .......lol....N8QZH

[@w2aew]

+Matthew Miller Yes, I've seen this same scope with at least 4 different nameplates on it. A nice, very useful, basic scope.

[@TonyButchT]

Excellent lesson all around! Looks like it was fun to kick back and tweak "ol' betsy"! Actually, this procedure is up next after a Eico 460 rebuild!

[@pcrengnr1]

Alan thx for sharing. As for the transient response adjustment, the picture in the manual shows ringing and you even commented about the ringing. I like what you ended up with, a nice square wave with no ringing. I'm with you, if I could've adjusted it so that I didn't get ringing but got the squarest wave I could I would've too. I wonder why they suggested adjusting the transient response so that ringing was present. By the book a little bit of ringing does give the widest bandwidth before falloff like a Chebyshev filter. However, the downside is the time domain suffers. I still like your solution. Again, thx for sharing.

[@igsaturation]

Nice work. That Heath scope looks almost new. Aside, the quality of the documentation are pretty rare to find in modern gear. It does serve to warn others looking to get an analog scope of unknown status over eBay that getting the parts replaced in one thing, adjusting it to factory performance is another.

[@dave-d]

Thank you. I am in the midst of an HP Agilent 1740A mega repair / refurb and have all this to come. Still chasing vertical jitter in this one. The gremlin has hidden itself well in this one!

[@rostlaur]

If your videos get the merit that they deserve I would suggest that your introduction salute the viewers from the 22nd century and after ;^)

[@w2aew]

Thanks! But really wonder how much of this will be relevant in the next century...

[@jorgesantos1225]

Great video! Thank you.

[@321reh]

Thanks Alan for another Great Video!!

[@judges69]

Thank you for this video, its just a hobby for me and you helped a lot.

[@Kennynva]

I have the problem at 18:51 in the video..where the vertical pips are not in alignment the further you get from left to right...I can find no adjustment in this old scope (Hitachi V-302)...what is the pot for this adjustment called in your scope..Thanks for all the fine work you do...I can tho turn the SWP VAR to get them to line up...

[@w2aew]

It looks like (from the schematic in the manual on Electrotanya) that the calibration adjustment for sweep speed might likely be a variable capacitor called CV510 shown on page 26.

[@Kennynva]

Strangely enough it was a pot not a VC and it was called (X1 H GAIN). I hate moving things to find out which one to adjust but sometimes you have to take the chance..Im going by a V-202 calibration..and seems close..just different VR and CV numbers...

[@MnACreations]

That was very informative. Thank you for creating the video.

[@dri50]

I just bought a Heath IO-4550 for hobby use and audio work. It's not coming with manuals, had to buy the assembly and user manual separately. I would think a quick inspection of the power supply electrolytics will be my first step before attempting calibration. Thanks for the video.

[@mdzacharias]

Just a thought - since I work on stereo equipment for a living, I think I would do the ch. 2 vertical sensitivity adjustment by overlaying it over ch.1 (after it has been adjusted) and adjusting so that the two channels match as closely as possible. Just my .02...

[@lwilton]

I've tried that, and it doesn't work as well as you would think. The problem is the trace lines are wider than the gradicule lines, and they are the same color, so you usually end up with the second channel being worse calibrated than the first channel. It is easier to do both per book, then A/B compare the results with the same signal fed to both channels, and make any tweaks that might be required to make them exactly match, if they will. Since it is an analog machine, they won't always match perfectly.

[@GaryGrove]

Enjoyed your video Alan! It does look strange to see you calibrating a unit that is less than 1 Gig!! 73's , Gary Grove

[@tubical71]

Thanx for this one, as i now know that i do not have to open my "new" "Vuko VKS220-16" scope to rotate the CRT for an all flat trace, as the little trimpot, you´re revering to at 06:40 has only "TR" written on the silkscreen of that vuko, and it´s just next to intensity, therefore i thought this is to trim the intensity. Now i know better. As that "TR" is AKA trace rotation. Thanx a lot for this, rather tiny but very useful, hint, as it prevents me to work that scope CRT :)

[@johnnaggo4002]

I have the same scope. For the analog part I can use the appropriate Hameg manual, but do you have any info on the digitizing section?

[@tubical71]

I got the whole documentation from vuko, a big solid A4 letter folder, about 300+ pages....

[@krisztianandre]

TubiCal do you know how to display the stored waveforms, or you can only access the memory trough the gpib interface?

[@anthonyroby296]

Very tinely since I just picked up a Tek 2225. I haven't played around much with it yet to see if it's in need of calibrating.

[@seancastledine8983]

Good video. Nice work.

[@Yazeed834]

A great job as usual!

[@tanukicyber]

Thanks for the informative video. What did you use as you signal sources? I have a Tektronix 465, like you too. I wish you had done that scope, but I'm not complaining! It's nice to see what you had to do, so I'm aware of what is coming down the road for me and my oscilloscopes.

[@w2aew]

tanukicyber I used a Tek AFG3252 - fast and accurate enough for these old analog scopes.

[@BruceNitroxpro]

make sure you recap it first... and test the power supplies... making sure you use 117 vac through a good isolation transformer at test time

[@THESKYMASTER]

Very good video, thanks!

[@Nox665]

18:30 what is that "time mark" on the screen? Just a short pulse?

[@w2aew]

It's an "exponential fall" waveform available on many arbitrary function generators. This is very similar the waveform used on many legacy time-mark generators. Any periodic waveform (square, etc.) can be used as long as it's frequency accuracy is sufficiently better than the scope's timebase accuracy.

[@boonedockjourneyman7979]

Excellent. Thank you. Why are “experts” unwilling to try things like this?

[@gamingSlasher]

Top notch! All my thumbs up!

[@FullElectronic]

I just need to know what nomenclature HP uses for trigger offset.

[@MrMac5150]

Very good.

[@yurin5227]

Hi, I like your video, very easy to follow. I've got a bit of a problem, wondering if you could help. I picked up the same scope off an auction, but there's an electrical problem I can't quite track down. Is it possible to get a scan of the electrical diagram that came with it? Mine came with no manuals. I'd really appreciate it.

[@caulktel]

Good video Alan, you make it look easy. Do you know where I might find service manuals for my two Kikusui oscilloscopes. I have a COS5040 and a COS5100. They both work great, but could stand to be calibrated.

[@w2aew]

You might try the manufacturer - they will sometimes have the service manuals available for free. You may have to contact their customer service.

[@joeobrien1888]

Alan, this is FANTASTIC. About the best I've seen in the way of calibration, you sound like you might be a teacher. I worked with these scopes for about 25 years (DEC) and have the exact one you use in this video. Do you know where I can get the Service Manual? I've looked, but it's pretty hard to find. Thank you again for such a good and professional video.

[@w2aew]

+Joe O'Brien I'm not sure where to find the manual. I happen to have gotten one with the scope.

[@frecuenciajuaniyo]

very nice video

[@Kennynva]

At 9:35..which pot, or should I say what is the adjustments pot name being made to make it stay the same when a and b are in the ADD mode..???

[@w2aew]

According to the manual, that would be VR343.

[@Kennynva]

i meant on any scope what is the adjustment name...I am the one email you about the manual on the scope Hitachi V-302. Like one adjustment is the gain...another is the astigmatism...which name of the adjustment, adjust the difference when on ADD, or DUAL..thanks for your help..

[@thecow2756]

this scope has been also sold as teklab osc-25 and mine has a issue where the up/down position is faulty on both channels and has to be set fully to one end to show on the screen so need to do checks on where the fault is at

[@aposhanski]

Hello Alan. My name is Alexander R2DHL. I have got an old Tek 2445b and this is my favourite scope. About a month ago an error appeared: test 4-11 (calibration constant checksum) and everything pointed on a nvram chip NEC D4364C-12LL fault. So I have replaced it with the UT6264CPCL-70LL chip (it has more memory and a litle bit faster). The battery was made in 1988 and there was 3.6 volts on it but I have made a decision to replace it too. Now I need to calibrate my scope. The calibration manual that I have found on internet is not easy to understand because I am doing that for the first time. 2445b is a pretty common scope but I could not find any video instructions for the calibration procedure. I will be very appreciated if you will help me with my problem.

[@pji6494]

Job well done!

[@josealfredobh]

Hi, is there any procedure for checking the calibration status of the analog oscilloscope, without disassembling it ?

[@w2aew]

You basically have to run through a performance verification, which is putting known signals into the scope and observing if the scope is displaying their properties properly.

[@jimis04]

Congrats! And liked! I have the same exact oscilloscope but as a brand it writes MiteK mk4300..im so happy that the only complete oscilloscope calibration on KZbin is on my oscilloscope... Must say that the insides look completely the same as well. just the operation led is red on mine, not green but when possible I will change it because it's annoying and looks awkward

[@bigbread9000000]

I have the same scope with the pintek brand name. I was wondering if there was a calibration for the cal lug?

[@w2aew]

Yes, there are adjustments for frequency, duty cycle and amplitude. I didn't include them in the video because I didn't want to give the impression that the CAL signal could be used as a cal reference. It's only intended purpose is for probe compensation. Even if it is adjusted properly, it won't be stable enough to be a cal reference signal.

[@worroSfOretsevraH]

Hi Alan. I have a 20MHz GW-Instek GOS-620 scope, but unable to find a calibration manual for it. I saw on Tek's website that they perform such calibration, so I assume they have the manuals. I was wondering if maybe you have one, or can get one somehow? Would be of great help, so I can finally calibrate my oscilloscope. Thank you.

[@w2aew]

I"m sorry, but I don't have access to service department documentation. From a teardown video I saw on KZbin, this scope looks to be easily servicable, and the trimmers on the two boards look to be clearly labeled. It shouldn't be too hard to figure out a bulk of the calibration steps.

[@worroSfOretsevraH]

Yes you are right. I've already done half of it, but still having problems with the add-balance adjustment. No matter how I set it, there is always some error when I switch to ADD. Thank you.

[@w2aew]

I don't know about you, but I very rarely (if ever) use the ADD mode except for the very occasional use of ADD INVERT to get a measurement across a component. So, I wouldn't sweat it too much. I saw that Elektrotanya has the schematics for this scope, but no calibration instructions. Might be worth writing GW-Instek through their site to see if they can provide this for you.

[@w2aew]

Here is the calibration adjustment instructions for that scope. drive.google.com/open?id=1YHxSVJvriqylNcCsGmSWlb5qIdEffw2x

[@worroSfOretsevraH]

Wow! Very kind of you. I was trying to contact the manufacturer, but received no response . This world would be a much better place with more people like you. 73.

[@MikeRR142]

Thanks for this great video! Very helpful. Was wondering about the 50ohm terminator, why was that used? Didn’t see where that was required in the video shots of the manual you were using. Is it because you are not using a probe but directly connecting to the waveform generator?

[@w2aew]

I used it to minimize reflections and distortion from my signal generator, especially on the square wave signal.

[@scottson2]

Very informative video.. What brand and model of HV robe is that? I'm looking for one currently.. thanks.

[@w2aew]

+scottson2 It's an old RCA WG-297 - it can be seen in more detail in my video on High Voltage Probes: kzbin.info/www/bejne/Y5Cve4uBgcx8j8U

[@mikezike1]

Thanks for the wonderful video. Although I have both digital and analog scopes, I really like the analog for the real time stuff. Is there an alternative to the Time Mark generator for calibration?

[@w2aew]

Any signal or function generator whose frequency accuracy is better than the scope you're calibrating, you can use.

[@Gw0wvl]

Another Great Video ... Thankyou .

[@kgsalvage6306]

Hello , Been watching your videos on oscilloscopes. I just got a Sperry 620C . It's in excellent condition , but I have an issue with the vertical position . It won't come down to center on either channel . It's all towards the top and off the screen . Any thoughts on what to look at . Any help would be greatly appreciated . Thanks

[@w2aew]

I'm not familiar with that scope, but if the vertical offset problem is common to both channels, then you can rule out the vertical preamps. I would focus on the CRT vertical plate amplifier and driver stage.

[@millerellen2258]

Thanks for you video

[@carlapeterchris]

I have the exzact same Heath 4552 oscilloscope. Where would I get the service manual for it?

[@w2aew]

I'm not sure - the user manual (with the calibration info) came with mine.

[@gwell12]

I have the exact same model oscilloscope. & I cannot find any documentation on how to calibrate this unit. Where can I obtain such information?

[@w2aew]

I'm not sure where to find it - the manual I used came with the scope when I bought it.

[@gwell12]

***** I don't know if this is asking too much, but i would gladly pay you for a PDF version of the calibration section. I bought this model second hand off of Craigslist.

[@alanwolke6253]

Email address?

[@Roy_Tellason]

Speaking of having the proper documentation, can you point me to where I can get a service manual for my Tek 2246?

[@w2aew]

Here are two sites, one is actually on tek.com: www.tek.com/manual/2246-service-manual w140.com/tekwiki/images/c/c6/2246_service.pdf

[@gixerags750]

Love your channel..is there any way of making this procedure less dangerous? eg an isolation transformer etc? or are the CRO votages , unavoidable just way too high? Thanks in advance.

[@w2aew]

The CRT voltage is very high, not much you can do other than use extreme caution.

[@gixerags750]

​@w2aew can this calibration process still be partially successful by skipping the high voltage crt step? 73

[@JIMO415]

Hello sir, I have watched a few of your scope videos and they are very helpful. I appreciate them. I have been playing with Tektronix 465 units and now have 3 of them. I was able to get the first 2 going and I have a question as I dig into the third regarding the use of an old Triplett 630 VOM to measure the HV supply. It has a 6000 volt range but I was wondering if it has too low of an input impedance to measure the -2450 on the Tek 465 (doing this measurement hands off of course). I understand the HV probe would be the better and safer thing to use here ( I do not have). I was just wondering your thoughts if you care to share. Thank you , Jim

[@w2aew]

It should be OK. THe 630 is a 20,000 ohms/volt meter, so it will have about 120Mohms of resistance when used on the 6000 volt setting. Just remember to use the special 6000V jack on the front panel, and be EXTREMELY cautious as this HV can be lethal. Make sure the probes you are using have insulation rated high enough.

[@JIMO415]

@@w2aew Yes and thank you sir. yes, probes are a concern at this point. Jim

[@JIMO415]

Yes sir it worked well, thank you. I was able to confirm complete proper voltage of all supplies. I now just have to find out why there are no traces on either channel and just a dot when beam find is pressed.

[@w2aew]

@@JIMO415 If you can move the dot back and forth with the horizontal position control, then that tells you that the horizontal driver (and likely horizontal amp) are OK, so then focus on the sweep generator circuit. Nice thing is that you have 3 of them - one to test with, one to verify what the waveforms and voltages are supposed to look like, and one to troubleshoot - ideal situation!

[@JIMO415]

@@w2aew yes, I agree at first. As I get into it, I can't duplicate the waveforms in the manual with with what I find on the test points of the working scope. But it was late and I was tired so ? This one will be a learning struggle! Yes, the dot does move horizontal back and forth about an inch as well as the vertical up and down with beam find pushed in. It appears as if each channel has it own sweep generator. So if there is no trace in either channel, it must be a single, common to each channel issue I would think?? we will see eventually I hope. Jim

[@MrDIMITRIOUifyable]

i did find your video very interested , . i do have an oscilloscope in my position the DM64 Analogue storage oscilloscope i have not a clue how to get it working for so long . i do have all manual seen your video i am going to have a go

[@larryrenaud7462]

Great video just picked up this scope, question where did you find the service manual.

[@w2aew]

The service info is in the back of the users manual that came with the scope.

[@larryrenaud7462]

I got the scope but no service manual, can't find one on line 73VE3BHM

[@thrill4kill143]

What signal source did u used to "cal" bandwidth, response time and time base?

[@tucker934]

Just gotten a Hitachi V-209 20MHz, and I can’t seem to find the calibration manual/instructions for it. The V-212 is also A 20MHz scope and there’s one for it, but coming up dry on the V-209 any help?

[@TheHarpanOnly]

Do you have digital copy of that scope? I have an old oscilloscope, not same brand, but has very similar button layout.

[@w2aew]

Here is the manual I used: drive.google.com/file/d/0B8Kvsw95jCqITG9XcDc0QnAwbHM/view?usp=sharing

[@TheHarpanOnly]

@@w2aew thank you for your kindly reply and support. Hope the best for you. DE YD2BLH

[@TheHarpanOnly]

Your schematic is 99% identical with my oscilloscope. And I successfully repair it becausd that schematic. I just did it. Laat night I want to calibrate my oscilloscope, and I am shocked to realize that the pcb layout is 100% different. :D

[@mian2zi3]

Great video, thanks! I just picked up a used Tek analog scope I'm going to try to repair/calibrate. This is my first time working with with a device with high CRT voltages. Where did you get that insulated screwdriver? I'm having trouble finding something spec'ed above 1kV, let alone the voltages in the scope (14kV).

[@w2aew]

mian2zi3 The screwdriver was made completely of plastic - it was purchased as part of an "alignmnent tool kit", typically used to adjust the RF coils in radio and TV receivers.

[@eldenchang]

Hello Alan, Thanks for another great video. Where can I get these small and nice BNC cables you are using? Are they sold like this or did you make them yourself? What kind of cable is it? It is so nice and thin. Thanks

[@w2aew]

Those are made using RG-174 type coax. I have made some myself, but I have also purchased several from eBay. I've had good luck with items from this ebay vendor: stores.ebay.com/adapterconnectorpigtailcable/

[@eldenchang]

***** Thanks for the advise of the cables, I ordered some from this vendor an hope they are good quality.

[@Giovanni2862]

Could you help me, what instruments are needs to calibrate a Tektronix 2465 ?

[@FullElectronic]

Hi Alan. What is the name of the adjust made at 16:02 where you adjust the wave to zero on the left side of screen? I have a hp1740A in need of this adjustment. My listening in english isn't so good but, you said trigger offset?

[@w2aew]

+CYBERRD58 Yes, it is the trigger offset adjustment - it is adjusted with the trigger on AC coupling, trigger level control set to the midpoint, then adjust the trimmer (assuming there is one) so that the signal begins at the middle.

[@FullElectronic]

Thank you.

[@FullElectronic]

+w2aew Thank you.

[@gixerags750]

Hi , i could really use your advise, my channel 1 is receiving a 1khz signal but my vertical position control will not bring the trace high enough to centre the trace.. channel 2 works fine.. it is a a Telinstruments TI 5252 25MHZ scope, . The correct waveform is there but is hanging way below the bottom of the scrren..very frustrating. Cheers

[@gregorystevens5173]

Hi Alan, thanks for the video and the very clear explanations. I'm somewhat new to the O-scope world and certainly new to scope calibration. I would love to have a generator like a 3252 but it's out of my budget at the moment. Are there less expensive (

[@w2aew]

+Steve Novosel Some of the new generation of inexpensive DDS based signal and function generators would be sufficient for many of the needs of checking/adjusting an old analog scope.

[@stephennovosel]

How critical is it to find one that includes a pulse generator with 1 ns or less rise time (for purposes of calibration of a 25MHz Heath 4552)?

[@w2aew]

+Stephen Gregory Not super critical given that the scope's risetime is about 14ns. But, I'd want to have a pulse that is a few ns or so. This can easily be done with some fast logic chips. See my video on the Schmitt Trigger oscillator. Note that several viewers have made some boards available.

[@JoaoFerreira-bi8wt]

Is the ripple at 11:38 normal, when you use the vertical magnification? I also get it on a second-hand analog oscilloscope that I bought.

[@w2aew]

For the most part, yes. This is a very sensitive setting, and the scope is picking all sorts of noise because the case is off of it.

[@JoaoFerreira-bi8wt]

***** Thanks! I thought it might be out of calibration.

[@nhnchannel5426]

Can you share this document? thank you very much

[@The8TrackChap]

Where do you obtain the plastic "insulated" screwdriver?

[@w2aew]

Electronics supply shops would often carry "alignment tool sets" which will include non-conductive tools like these.

[@The8TrackChap]

Are they ceramic?

[@w2aew]

Some are ceramic, others are nylon, delrin or other types of plastic.

[@mindingosafado]

The 100x high voltage probe, where do you get those from?

[@w2aew]

Test equipment dealers still sell them, but I found mine used at a ham radio flea market. You can find many for sale on Ebay too.

[@allprogear]

My scope display is not blue on my Heath 4552?What seems to be the problem?

[@w2aew]

My scope has a blue filter on the face of the CRT. It could be that yours is missing.

[@acolisys]

Another real master class, Alan ! By the way, I'd like to thank you for the spectacular knowledge that you spread through your videos ! Do you have any reference material / video about Delay Time / Dual Time Base oscilloscope calibration, please ? Merry Chrismas & Happy New Year ! Wish you all success, heath, peace, happiness and the best greetings from Brazil !... ^_^

[@w2aew]

This video should be what you need: kzbin.info/www/bejne/a2XVoK1ufrqijKs

[@acolisys]

@@w2aew Excellent, I'll watch it in a moment. Thank you ever so much !...

[@larryrenaud7462]

Hi Alan, again I need your advice. The scope I was restoring looks great using your suggestions, of Windex and alcohol. The potentiometers need cleaning. The scope is a Tektronix 422, some sites say don't use contact cleaner but replace them, that would be cost prohibitive, what is your suggestion. Thanks Larry

[@w2aew]

I've always had good luck with careful use of DeOxit.

[@mrnmrn1]

+w2aew Hi, I'm new on your channel. I'm not familiar with DeOxit, is it leaves some oil residues, or completely dries out? I have always afraid using oily contact cleaners in oscilloscopes, than later my fears has been confirmed when I saw a busted scope, which had its Y attenuator switches insulted with oily contact cleaner. The oil penetrated inside the compensating trimmer caps, made it impossible to set them properly, as the oil changed their capacitance so much, and probably increased their dissipation factor at high frequencies... Even the probe compensating 1kHz square wave of the built-in generator looks horrible in some ranges, while other ranges are better, but non of them are perfect. In your opinion, all of the trimcaps needs to be replaced in the attenuators, or maybe an ultrasonic cleaner filled with isopropanol would help? This isn't my scope, I've seen it at work, but it's just so sad to see that beautiful 100MHz Iwatsu in that condition... I personally have a Leader LBO-508, a HP 1223A, and the Hungarian clone of the Tektronix 647 (EMG 1555 / TR-4653), all of them needs to be calibrated, but I have no calibrated generators, so I will probably do the calibration via comparing the 'scopes under test' to a calibrated scope at my workplace.

[@w2aew]

+mrnmrn1 Yes, you do have to be careful with these cleaners that leave a lubricant. Use them sparingly, avoid overspray, etc. In cases where you have open contacts, using ordinary white paper soaked in isopropyl alchohol used as a wipe on the contacts works well. It is hard to say about the trimcaps. Replacement would likely be best, but tedious and expensive, so it may be worth trying some other methods first.

[@mrnmrn1]

+w2aew Thank you for your answer. I used to use the white paper trick on open contacts, but usually I start with dry paper, as it rubs the surface more than isopropanol wetted paper. My second step used to be the isopropanol wetted paper, to remove the rubbed-off oxide residues. If the oxidation is more serious, I used to wet the paper with one of those ugly, oily contact cleaners, as they are great silver oxide solvents. This is the only way I use lubricant type contact cleaners in sensitive equipment. I used to use thick silicone grease to lubricate contacts (especially in potentiometers), as it lasts longer, and doesn't penetrates everything on the board, just stays on the contacts for years, protecting them from oxidation.

[@barn5923]

thanks enjoyed this very much

[@cesargabrielachar344]

HOLA AMIGO...TENGO UN PINTEK PS1000 ..EL PROBLEMA QUE TENGO ES QUE PERDI UNOS RESISTORES DE LA PARTE DE ALTO VOLTAGE QUE ALIMENTA LA GRILLA Y CATODO..TENDRIAS EL CIRCUITO? SALUDOS ..

[@w2aew]

I am sorry. I have sold the scope and do not have the circuit schematic. Lo siento. He vendido el alcance y no tengo el circuito esquemático

[@KungKras]

Is it normal for a waveform to change amplitude when turning the position knob or is that an indication of something being broken?

[@w2aew]

The amplitude shouldn't change when you change the position. In this case, I was adjusting the position at the same time as adjusting the internal trimmer (so that the signal lined up with the graticule).

[@KungKras]

@@w2aew Thank you for the reply! Then I know for sure that my analog oscilloscope must be broken. Hopefully it's just a capacitor that's gone bad too.

[@Giovanni2862]

Could you explain how to calibrate the Tektronix 2465?

[@w2aew]

This is much more involved than the simple analog scope shown in this video. The calibration procedure is outlined in about 30 pages of the service manual, which you can find here: w140.com/tek_2465a_2467_service.pdf

[@Giovanni2862]

w2aew I have download this www.download-service-manuals.com/download.php?file=Tektronix-1780.pdf&SID=4nqic6fff8m1u805ml264m81l5

[@Giovanni2862]

w2aew It is need a Time Marker Generator but I don’t have it.

[@billwilliams6338]

w2aew, any reasons why the vertical sync is reference to the power line frequency at 60hz? I'm not sure what the advantages are that the vertical sync is reference to the power line frequency at 60hz. The vertical oscillator and horizontal oscillators +VCC is not at +9vdc and +12vdc like most common oscillators circuits, any reasons why they use a much high +VCC voltage for the V&H oscillators in oscilloscopes? in the XY mode it turns OFF the V&H oscillators and the XY deflection amplifiers need a voltage at the Oscopes input channels. The XY Deflection amplifiers output a "very high current" to the V&H deflection Yokes to the CRT which bends steers the electron beam?

[@w2aew]

I don't know what "vertical sync" you are referring to, with respect to 60Hz, in an oscilloscope. Older service grade oscilloscope do have a SYNC control instead of a trigger, but it is typically used to pick-off a portion of the input signal and then try to "injection lock" the horizontal oscillator. These scopes have the option to switch the SYNC to the 60Hz line frequency - which can be useful when looking at things that are related to the line frequency such as linear power supply ripple. Oscilloscopes don't have vertical oscillators, as far as I know. The horizontal oscillator in an old service grade recurrent sweep scope, or the Sweep Generator in a more modern triggered sweep scope, ultimately has to feed the horizontal amplifier and driver. Depending on the design, these circuit may need a higher drive voltage than a 9 or 12V powered circuit can provide. The X and Y deflection amplifiers generate the high VOLTAGE necessary to drive the deflection plates in the oscilloscope. TVs use magnetic deflection using coils on the yoke, steering the beam magnetically. Oscilloscopes generally use deflection plates, steering the beam by the electric field between the plates.

[@billwilliams6338]

@@w2aew thanks for the help, what is the Common general "reference frequency" for the Horizontal oscillator in Oscilloscopes? The horizontal oscillator is sync to what frequency in oscilloscopes? if oscilloscopes don't have a vertical oscillator how does it draw the vertical images which would be a voltage waveform on the oscilloscope? The Time base control on the oscilloscope is changing the sweep time of the Horizontal oscillator? the Volts per division knob control is changing the oscilloscopes INPUT channel#1 or#2 amplifier, but the output of the Volts per division amplifier is "connected" to the Horizontal oscillator and Vertical Oscillator to draw the waveform on the CRT oscilloscope screen?

[@w2aew]

@@billwilliams6338 For analog oscilloscopes, there is no "reference frequency" for the horizontal circuit. Only the very basic service-grade scopes (called recurrent sweep scopes) have a horizontal oscillator. This oscillator frequency is adjustable on the front panel. It is not derived from a PLL or syntheziser, so it doesn't have a reference. Triggered sweep scopes don't have a horizontal oscillator, they have a triggered sweep or ramp generator. Again, no reference frequency involved. The timebase control adjusts how fast the ramp voltage goes up (which controls how fast the beam is swept across the screen). No oscillator is needed or used on the Vertical path. The input signal is amplified and applied to the vertical deflection plates to move the beam up/down in proportion to the input voltage.

[@billwilliams6338]

@@w2aew thanks for the help, this doesn't make sense to me. Triggered Sweep Oscopes are using what kind of circuit to do the triggered sweep? To do a sweep you would need an oscillator circuit I thought. The timebase control will "change" the times per division giving your more or less cycles of the waveform but you're saying that its only adjusting the triggered sweep circuits ramps PEAK voltage? I would think its adjusting the ramps timing/frequency of the oscillator circuit, not the ramps voltage because you're getting more and less cycles of the waveform from the time per division squares on the Oscope screen so I'm very confused how the ramps voltage would do this.

[@w2aew]

@@billwilliams6338 In a triggered sweep scope, a triggerable ramp generator is used to move move the beam from left to right on the screen. The horizontal timebase setting controls how quickly or slowly the voltage is ramped, thus controls how quickly the beam is swept from one side of the screen to the other. The peak voltages (starting and ending voltages) are the same regardless of the timebase setting - the timebase setting only controls the speed at which the voltage changes.

[@AmirPourkashef]

I have a leader lbo 506, Volt/Div are totally jumped up and down. How can i fix them?

[@alanwolke6253]

Sounds like dirty contacts on the vertical Attenuator switch. Careful use of appropriate contact cleaner can often be used.

[@AmirPourkashef]

@@alanwolke6253 thank you sir, I'm going to clean it with a non lubricant one and tell the results here. (So there's no trimmer pot to rescale and balance every single volt/divs?)