hybridfree/eevblog-posts huggingface dataset:
Tektronix 465B B Trigger Pot/Switch Alternative Part Numbers - Page 1
Forum section: electronics / repair

author: kayvee
author_rank: Regular Contributor
timestamp: August 23, 2019, 06:42:48 am
content: So mine is knackered, the Tek part number being 311-1192-00. These are as rare as the proverbial rocking horse turd.Last year I looked into this and found a bunch of alternate Tek parts numbers, but for the life of me can't find them again! It's a bugger getting old.So if anyone knows alternate parts numbers and possibly where I can source it would be appreciated.

author: Hornethandler
author_rank: Contributor
timestamp: August 23, 2019, 12:35:34 pm
content: Looks like there's one here.https://www.sphere.bc.ca/test/tek-parts/tekpots.html

author: woodchips
author_rank: Frequent Contributor
timestamp: August 23, 2019, 05:28:40 pm
content: These switch pots are also found on the 7000 timebases, just looked up the 7B80, but from memory also the 7B85, 7B53, 7B92.I had a pile of these after scrapping lots of 7000 plug ins that I thought Sphere wanted, but never came back to me, all binned.

author: kayvee
author_rank: Regular Contributor
timestamp: August 24, 2019, 04:34:43 am
content: Quote from: Hornethandler on August 23, 2019, 12:35:34 pmYes I saw that one but it's more than I paid for the entire scope, and that's before I ship it half way around the world.Quote from: woodchips on August 23, 2019, 05:28:40 pmThanks, I will check out the service manuals for part numbers.
Tektronix 468 oscilloscope - Page 1
Forum section: electronics / repair

author: wipso1
author_rank: Newbie
timestamp: October 30, 2023, 07:16:05 pm
content: Hi, i recently equire damaged tektronix 468 scope. It seems like horizontal time base malfunction like in the picture. Nothing light up on display untill "find" button is pushed Any hope for repair??PS: Sorry for my bad english

author: perdrix
author_rank: Frequent Contributor
timestamp: October 31, 2023, 01:29:14 pm
content: That looks promising to me - you have a sweep so the trigger circuit is at least partly working, as is the horizontal sweep generator and amplifier.I'd certainly take it on! You should get hold of the service manual (either QService or Artek Manuals), and also take a look at:https://vintagetek.org/troubleshooting-your-oscilloscope/Which was originally written for valve (tube) based 'scopes, but most of what it has to say is highly relevant to mostly solid-state 'scopes like the 468. The 468 is of course complicated somewhat by its digital side, but you can get the analog side working first and then look at the digital stuff.David

author: Runco990
author_rank: Frequent Contributor
timestamp: October 31, 2023, 05:05:24 pm
content: Have you tried setting up your trigger and horizontal time base correctly?

author: wipso1
author_rank: Newbie
timestamp: October 31, 2023, 05:55:25 pm
content: Thanks a lot.Quote from: Runco990 on October 31, 2023, 05:05:24 pmIf you mention setting up knobs at front panel. Yes, i tried different positions.Quote from: perdrix on October 31, 2023, 01:29:14 pmI will try my best to bring it back to live.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: October 31, 2023, 06:42:08 pm
content: I had a very similar problem on my Tek 475 oscilloscope. When pressing beam find the trace would show but advancing the intensity and moving all the horizontal and vertical controls didn't work. Even disconnecting all the horizontal and vertical deflection pins would now show a trace except for pressing the beam find button.Turns out all that went bad was one transistor on the input of the external Z-axis input shorted.My first step in your situation would be to trouble shoot the Z-axis amplifier.If the Z-axis amplifier is working, try looking at the trigger board. My 475 gets it's blanking signal from the trigger board.Not sure if the 468 and 475 work similarly enough that this advice is useful, but they're close matching so I hope they work in similar ways.
tektronix 468 service rom u456 and test counter ic  part number 067-989-00 - Page 1
Forum section: electronics / repair

author: xantia_99
author_rank: Contributor
timestamp: October 17, 2020, 01:43:18 pm
content: HiDo anyone knows anything of above items. It's useful in repair of digital part of Tektronix 468 even without signature analyzer. However, a signature analyzer would certainly help.I do not have a real problem, but just interested.Best RegardsStephan

author: PaulAm
author_rank: Frequent Contributor
timestamp: October 17, 2020, 02:56:08 pm
content: There is a long running thread on 468 repair going on in the Tekscopes io group and the service rom image was recently posted the in the files section

author: xantia_99
author_rank: Contributor
timestamp: October 17, 2020, 04:37:16 pm
content: HiI could explain a bitI got this tek 468 and look for A/D simulator test rom.It's an special item and it was sold separate from Tektronix for repair/test A/D with a Signature Analyzer as HP 5005BService rom and test counter IC part number 067-0989-00.You remove the A/D in U456 and put in the test counter chip instead. Next step is remove U565 and put in the service Rom insteadThe other two original rom could be bought on ebay but that is not the same case.Best RegardsStephan

author: xantia_99
author_rank: Contributor
timestamp: October 18, 2020, 08:53:08 am
content: HiSince yesterday I found out it will soon be possible to buy part number 067-989-00 on Ebay and that will solve my problem. However I also need a Signature Analyzer for that.Best RegardsStephan

author: jrseattle
author_rank: Newbie
timestamp: January 19, 2022, 02:39:12 am
content: Hi, Stephan.I wrote a note about this test counter IC and problems with the TRW A/D converter used in the Tektronix 468. It's attached.Re. the Service Rom, you can program one yourself in a 28-pin 8KB Eprom chip but you'll also have to make a 24-28 pin socket adapter since the 468 used 24-pin ROMs, now obsolete.

author: xantia_99
author_rank: Contributor
timestamp: January 19, 2022, 04:55:39 am
content: HiThank you for your reply.I will look into it. My Tek468 project have been very passive for a while, until now, I just got a CT-3 for calibrate the vertical input as well as A and B sweep.Best RegardsStephan

author: edavid
author_rank: Super Contributor
timestamp: January 19, 2022, 05:12:31 am
content: Quote from: jrseattle on January 19, 2022, 02:39:12 amNote, the J in TDC1007J is just a package suffix, not a speed grade.QuoteYou could use a 24 pin MCM68766 or CY7C264 EPROM if you have a suitable vintage PROM programmer.
Tektronix 475 +15V power rail issues - Page 1
Forum section: electronics / repair

author: Warsp
author_rank: Contributor
timestamp: July 21, 2023, 06:35:24 pm
content: I recently got a tektronix 475 and after replacing all of the filter caps and all of the underrated tantalum capacitors, the 15V rail is still not working. I narrowed the problem down to the +15v unreg rail which is also low but I don't know exactly what the problem is. I initially suspected the bridge rectifier but after testing it with my oscilloscope component tester against a working rectifier, it appears to be working. I also tested the +15v unreg rail without the fuse going to the crt circuit and removing power from all boards besides the main board but the problem was still there. I don't know what could possibly be making the +15v unreg rail go low so maybe the rectifier is actually toasted. There is ~18VAC on the transformer winding so thankfully I think the transformer is fine.Supply voltages+50V 50.0V+110V 111.3V+15V 1.7V+5V 4.7V-15V -3.2V-8V 0.4V+15V unreg 0.4V+50V unreg 71.9V+105/160 10.7V -multimeter might be broken as 146.4V appears later down the circuitSupply resistances all from + to -+50V 2.73k+110V multimeter can't decide+15V 64+5V 23-15V 12.51k-8V 32+50V unreg multi meter can't decide+105/160 no resistance or greater than 2M-8V and -15V are regulated by +15V, so it is expected that they wouldn't work. As for the resistance either my scope is very messed up or my cheap hardware store multi meter is acting up. There was definitely a bad filter cap and some shorted tantalums on the +15V rail which may have cause the mains fuse to blow before I got it.Thanks for the help

author: Warsp
author_rank: Contributor
timestamp: July 23, 2023, 03:57:59 am
content: The problem with the +15v rail was that the + pin on the filter cap was not soldered to the pcb on both sides and was not connected to the bridge rectifier. All of the power rails are now good and the crt shows a dot on part of the screen. Unfortunately it seems that a lot of the crt control circuitry is messed up, so no trace yet.
tektronix 475 - Page 1
Forum section: electronics / repair

author: Bogden777
author_rank: Newbie
timestamp: March 15, 2021, 05:35:23 pm
content: can anyone tell me why this screen is ghosting in sections

author: Bogden777
author_rank: Newbie
timestamp: March 15, 2021, 05:41:58 pm
content: another picture

author: pbarton
author_rank: Frequent Contributor
timestamp: March 16, 2021, 08:44:38 am
content: My guess, possibly a tube defect. The CRT may be (in the early stages of) losing its vacuum. The electron beam could be hitting some gasses and you are seeing backscatter electrons? If this was true then the only solution is a new CRT.

author: David Hess
author_rank: Super Contributor
timestamp: March 16, 2021, 12:46:18 pm
content: If you apply no input signal and use a slow sweep so that you can track the spot visually across the CRT, you will see a "ghost" which follows the spot across the screen up to the half-way point and then precedes the spot the rest of the way. This ghosting is caused by electrons scattered from the CRT's scan expansion mesh which the beam passes through, and may be what you are seeing.

author: pbarton
author_rank: Frequent Contributor
timestamp: March 16, 2021, 10:45:21 pm
content: A short video would aid further diagnosis.

author: james_s
author_rank: Super Contributor
timestamp: March 16, 2021, 11:10:55 pm
content: Quote from: pbarton on March 16, 2021, 08:44:38 amI doubt it's losing the vacuum, it takes very little gas in the tube for there to be lots of corona and arcing in the neck. It could very well be a mechanical fault in the electron gun assembly though. Is this one of the scopes that has a microchannel plate tube? I recall hearing that those are exceptionally fragile.

author: helius
author_rank: Super Contributor
timestamp: March 17, 2021, 12:05:25 am
content: Quote from: james_s on March 16, 2021, 11:10:55 pmNo, only the 7104, R7103, 2467 series, and 11302 have MCPs.

author: David Hess
author_rank: Super Contributor
timestamp: March 21, 2021, 07:37:05 pm
content: Quote from: helius on March 17, 2021, 12:05:25 amIt does not matter for this but CRTs which include an MCP cannot use a scan expansion mesh like I described above because the MCP would intensify the ghosting from the mesh to such an extent that the resulting display would be useless. MCP CRTs still have scan expansion but use a quadrupole box lens instead.

author: josh132
author_rank: Contributor
timestamp: March 21, 2021, 08:54:12 pm
content: Do you have B mode on? If so thats the problem. B mode is meant to use the delay knob to make very precise measurements.
Tektronix 475 PFP Capacitors - Page 1
Forum section: electronics / repair

author: Saberwind
author_rank: Newbie
timestamp: August 29, 2022, 02:13:02 am
content: Picked up a Tektronix 475 (high serial) at the local ham fest. Powers on, no trace or dot.Picked up the service manual, ran through low voltage system checking TP voltages and resistances on the A9 board against the tables. Voltages seem fine. Resistances mostly fine, except the -15 power shows a very high Ohm reading and the related C1472 capacitor's resistance readings aren't showing similar behavior to its neighbors.C1472 is 290-0583-00, 3000uF & 35vDC. Appears to be this guy:https://www.qservice.tv/vpasp/shopexd.asp?id=9332&bc=noI'm not familiar with these PFP type electrolytics.Am I looking at 4 pins that would need to be desoldered?Can't seem to find exact replacement available right now. Any suggestions for alternative part?More details:vDC testpoint readings+50v = 50.06+15 = 15.01-15 = -15.01+5 = 4.987-8 = -7.96+110 = 111.2+105/+160 = 141.7+50 UNREG = 68.4C1452 = 9.19C1462 = 13.02C1472 = 24.52U1454 pin 8 = 23.73Pin 3 = 15.00Pin 1 = 16.92Pin 5 = 4.986Pin 6 = 4.986Pin 7 = 6.52Pin 2 = 15.01Pin 4 = GND.... Need to double check U1464 pins still.VR1418 = 24.83Ohm testpoint readings, + on component, - on component+50v = 2.740k, 2.714k+15 = 65.5, 65.2-15 = 41.08k, 67.4k <-- C1472 is related+5 = 44.5, 44.5-8 = 33.6, 33.3 <-- Need to double check+110 = 32.90k, 32.15k+105/+160 = 35.59k, 34.46k+50 UNREG = 47.60k (69.20k), 38.00kC1452 = 8M <-- +5 railC1462 = 0 <-- -8 rail. Second test showed value.C1472 = 0 <-- -15 rail

author: Bruce1956
author_rank: Newbie
timestamp: August 29, 2022, 07:32:35 am
content: Hi Saberwind,I had a 475 with a similar problem in the C1472. I'm not at home right now, or I'd give you the replacement capacitors I used (I changed out all of the big capacitors in that section), but I'm not at home to check. I got tons of great information from the knowledgeable, helpful, and friendly folks at TekScopes@groups.io, and I highly recommend you search there.There are also some excellent adapters available athttps://www.ebay.com/itm/275258776339?hash=item4016b39b13:g:vwsAAOSwMxRgeyzufrom seller cuog. These little PC boards make the job of upgrading capacitors much easier, and they are made specifically for the 475.Good luck with your new project!
Tektronix 475 repair question - Page 1
Forum section: electronics / repair

author: kanakun
author_rank: Newbie
timestamp: May 01, 2023, 02:21:10 am
content: I have a Tektronkix 475 that i purchased but the only way i can get a trace to show up is the a inten setting I don't believe this is normal from what i have seen with other scopes. I don't know where to start with trying to repair this so I came here to ask for help.tia, Nathan

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 01, 2023, 04:30:16 pm
content: Manual is here :https://download.tek.com/manual/475Service.pdfI have one, it was in its time a very good scope and cost as much as an automobile.Look at the Table of ContentsGo to the Operating Instructions and thenObtaining Basic DisplaysSee if that is any help, let us know

author: Uunoctium
author_rank: Frequent Contributor
timestamp: May 01, 2023, 05:27:21 pm
content: weird trigger settings i.e. wrong channel, slope? Could lead to an blanked or darkended traceadded:in which position is your timebase knob? Coupled or delayed position? If i remember right, the 'A Int' works only on second.

author: MathWizard
author_rank: Super Contributor
timestamp: May 01, 2023, 09:51:11 pm
content: If you know the safety basics, start checking the various rail and test point voltages. IDK about the high voltages on these tho, so be careful, I wouldn't probe much of anything in the HV section. IDK how long those circuits would take to be safe after being powered off either.

author: kanakun
author_rank: Newbie
timestamp: May 02, 2023, 04:58:20 am
content: I finally got A-Lock-Knobs working occasionally but any adjustment often just makes the trace disappear. also i noticed after running the scope for a few minutes it destabilizes and I'm no longer able to get it to stabilize on the 30ma calibrator pin with any of the horizontal display settings and it just jumps around weirdly.Quote from: MathWizard on May 01, 2023, 09:51:11 pmThanks for this advise, I'll try doing it this weekend if I have the time to but I guess for the time being I guess I don't have a very functional oscilloscope

author: George Edmonds
author_rank: Frequent Contributor
timestamp: May 02, 2023, 05:19:32 am
content: HiLooks like you need to replace the power supply electrolytic capacitors, a standard problem with 475'sG Edmonds

author: dietert1
author_rank: Super Contributor
timestamp: May 02, 2023, 07:05:50 am
content: On german ebay there has been a clean and working 485 already for some weeks, looking for a good home. A 350 MHz scope at € 440.I remember fixing one of those as a student. There was a thick printed manual and it was a minor fault. At the time i was impressed by those gold plated circuit boards and the integrated high bandwidth amplifiers with separate pins for external RF terminators and feedback networks.Of course nowadays everybody prefers a DSO with color screen.Regards, Dieter
Tektronix 475 with DM43 - Repair - Page 1
Forum section: electronics / repair

author: Alfons
author_rank: Regular Contributor
timestamp: September 01, 2019, 06:41:00 pm
content: Last I bought a whole bunch of partly broken devices. Included was a 475 with DM43. CH1 was dead and the high-voltage eletrolyte cups shown a ripple of about 40VPP. Have then exchanged all Elkos, even if only 2 were really broken.Ch1 did not work because the vertical channel switch did not turn the signal thru. First thought the hybrid would be broken, until I noticed that there was an error in the logic control. One Resistance was high impedance. After replacing this, CH1 alives. The DM43 showed no plausible values, only 3.3.3.3: in the power supply of the device (hidden under a cover I found a power supply), in which a 12V voltage regulator was defective. A pain to expand the part.After exchanging some tantalum for Low-ESR electrolytic capacitors (with 100n SMD ceramic between the legs) and normal tantalum, the device works very well. It triggers extremely clean, (much better than my Rigol) the beam is clean and sharp. I'm really excited about the device. Also included was the appropriate Scope mobile.A 2467B was also there. Is already repaired.

author: Alfons
author_rank: Regular Contributor
timestamp: September 02, 2019, 06:36:58 am
content: It was a little difficult to find the right documents for the device. Possibly because of the DMM, the equipment is partly different from the normal 475, it is more like the 475A, but has an input sensitivity of 2mV instead of the 5mV of the 475A. Unfortunately, I find no service manual mached with this device. I wonder why the fixed 12V voltage regulator of the DMM goes defectiv. The device was also unsuccessful repaired earlier. In the power supply of the DMM, i found an newer 5V fixed voltage regulator. Some parts are not from the 70s. In the control of the vertical switch was a 74LS74, which I have again replaced by a 7474. Also one of the Electrolyt-Cups in the power supply has already been replaced. However, the previous owner did not get it up and running and so the device stood idle for many years.It was my first repair of an oscilloscope and it was really difficult for me to fix such a device. Without fun that makes no sense. All switches had to be cleaned to work properly again.In contrast, the repair of the 2467B was a breeze.

author: lowimpedance
author_rank: Super Contributor
timestamp: September 02, 2019, 10:38:39 am
content: I have one of these pair in the junk pile as well as the more common (i think!) 475a with the DM44 on top that only gives a burning smell.Thanks for the info, all handy when it comes time for a little bit of Tek 'surgery'.Also always nice to see these old timers kept from the e waste that little bit longer.
Tektronix 492 Spectrum Analyzer - case stuck - Page 1
Forum section: electronics / repair

author: M5
author_rank: Newbie
timestamp: September 10, 2021, 07:09:21 pm
content: Sooo, picked up a parts special, with broken handle on one side.I unscrew the 4 screws on the feet of the unit. The case "should" just slide off.It doesn't. It appears to be binding somewhere. Possibly related to the brokenhandle and the ultra tight clearances between the case and the unit. The casewill come out maybe 3 inches, 4 inches - then bind up so tight, it's not goinganywhere.Has anyone run into this kind of scenario before ? If so how was it resolved(to allow the case to be slid off) ?

author: KE5FX
author_rank: Super Contributor
timestamp: September 10, 2021, 07:38:17 pm
content: Usually this happens when there's a small concave dent in the cabinet that catches on something. Not much you can do other than force the issue, as far as I know. It's unlikely to hurt anything if you just yank on it, because the areas that are most subject to binding up are sturdy frame pieces.Watch out for the plastic covers on the HV and deflection amp, as they tend to stick out and can easily be damaged. That won't happen when removing the case but it is very likely when putting it back on.
Tektronix 492BP "Processor System Test, Please Wait." - Page 1
Forum section: electronics / repair

author: antimalware
author_rank: Newbie
timestamp: April 18, 2024, 08:32:37 am
content: Hi Eevblog forum.I just bought an used Tektronix 492BP. When i power it on it just stay stuck on message: "PROCESSOR SYSTEM TEST, PLEASE WAIT". And the unit feel warm.Did i just got scammed? What can i do?Thanks for your help.

author: m k
author_rank: Super Contributor
timestamp: April 21, 2024, 02:31:32 pm
content: What the manual has to say about the message?
Tektronix 495p SA fix and alignment - Page 1
Forum section: electronics / repair

author: hyl
author_rank: Newbie
timestamp: May 10, 2021, 12:14:11 am
content: 495P arrived with lots of fault, Auto Cal failure, funny response, 50dB lower than CAL signal, etc...the log amplifier debug and fix, lots of learning, fully response amplitude alignment,https://sites.google.com/site/linuxdigitallab/home/tektronix-495p-fix-and-alignmentand few useful/show off pictures.

author: hyl
author_rank: Newbie
timestamp: May 10, 2021, 12:19:35 am
content: most useful S/M is marked photo, and the fixing of logamplifer.
Tektronix 540 info - Page 1
Forum section: electronics / repair

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: July 25, 2021, 07:23:52 am
content: Ho acquistato da qualche settima un tektronix 540 rotto con il desiderio di poterlo riparare, infatti appena giunto a casa lo smontato ed ho verificato che lo stesso aveva bisogno della sostituzione dei condensatori della scheda CPU 672-2002-02 e della scheda board ho ordinato e sostituito sia i condensatori che la NavRam DS1245Y, purtroppo ho due errori uno riguardo la fail ++processor fail ++cal iniz

author: picburner
author_rank: Frequent Contributor
timestamp: July 25, 2021, 11:52:26 am
content: This is an English language forum, you will get more help if you write in this language.Fail++Processor:Does your oscilloscope have option 13 (lpt + rs-232 board)? Did you change all the capacitors there too?If you don't have opt. 13 there may be some corroded traces/vias on the cpu board or a bad ram (You need to look at the log file).Fail++Cal Initialization:This error message is due to the replacement of the nvram.Either proceed to the complete calibration of the instrument (a very simple job.....) or load the content of the nvram of another tds540 (in this last case the error should disappear but you will have a un-calibrated scope)

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: July 25, 2021, 12:31:20 pm
content: Grazie per la risposta si ho provato scrivere la navram prendendo il files dal sito, si non ho le porte 232 e pt sto provando a corregere il files in modo da eliminare le due opzioni.Però ho notato che quando scrivo il files su navram con wellom vp380 il files non viene scritto correttamente perche rilegendolo risulta leggermente diverso.Mi puoi aiutare, grazie.

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: July 25, 2021, 02:22:51 pm
content: Thanks for the answer yes I tried to write the navram taking the files from the site, yes I don't have ports 232 and pt I'm trying to correct the files in order to eliminate the two options.But I noticed that when I write the files on navram with wellom vp380 the files are not written correctly because binding it is slightly different.You can help me, thanks.P.S I'm sorry for the language, I use google translate
tektronix 540 navram options firm 2.00 possible upgrade to higher levels - Page 1
Forum section: electronics / repair

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: August 01, 2021, 06:09:02 am
content: tektronix 540 navram options firm 2.00 possible upgrade to higher levels; I replaced the capacitors and navram and installed the vers. 2F_13, but I had errors; later I was able to reprogram the same files in the old navram and now I have only error related to port 232 which is not installed.if anyone help me now i have the following problem even if i update the system date the next day i find that the date has not passed to the next day.Also I'd like to upgrade its current capability to some superior features; if this is possible I have read several posts but obviously I would like some advice to proceed in the most correct way.Also available to replace the cpu card with a higher-end one

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: August 01, 2021, 06:13:08 am
content: I add the photos of this latest update after rewriting the files in the old navram errors have been removed; but I am left with this flaw in the update date

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: August 01, 2021, 06:23:50 am
content: I am attaching photos for your help

author: picburner
author_rank: Frequent Contributor
timestamp: August 02, 2021, 07:13:16 am
content: Regarding the issue of keeping the date:The TDS540 doesn't have an RTC, so it is normal for it to lose the day and time, U1107 is a 128Kx8 SRAM only.Moreover this fact is specified in the user manual pag. 106 (chapter 3-44).

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: August 02, 2021, 12:40:59 pm
content: I have programmed a new navram and I have also removed option 13 so I have no more errors, but the date error remains. i think i could go deeper around the nav because there are jumpers that i might have to close like pc

author: Tektronix 540 (rotto)
author_rank: Newbie
timestamp: August 02, 2021, 12:43:51 pm
content: then if this is not a step forward, I have to buy a 500 Mhz probe what checks can I do to understand that it works perfectly
Tektronix 5441 Power Supply Faulty? - Page 1
Forum section: electronics / repair

author: Dead1y_Wolf
author_rank: Newbie
timestamp: October 31, 2019, 08:57:54 pm
content: Good evening guys,i got this oscilloscope gifted from my father and i really like the CRT ones.Only problem is it is not working properly.I desoldered the power supply to check it, because a cap blew up constantly.Following problems occur: The PSU can be adjusted by 2 variable resistors (on +30VDC and -30VDC) but turning those does nothing at allthe -15VDC Testpoint measures with -34VDC (almost the same as -30VDC testpoint)the 200VDC output is at 200VDC directly after the rectifier but 240VDC at the testpointIn the attachments are the board layout, the blank circuit and the blank circuit "colored" and filled in to give you guys more to work with.If you have questions or want the detailed parts list or photos, just ask me.I tried some measuring and testing myself to find out what the problem could be but it is not possible to me to understand the circuit enough to start troubleshooting.Let's say that I am a "beginner" in electronics and also try to understand everything that makes that scope work, because i find it interesting and always try to learn something new.And I also know that this project is wayyyyy to big for a beginner but meh... i like the scope and wanna use it.Thanks in advance for your help (if possible)RegardsMichael

author: randyhenke
author_rank: Newbie
timestamp: November 07, 2019, 02:35:09 am
content: Power off the scope and let the caps discharge and see if you have continuity from your testpoints to the bridge rectifier. I'm thinking that your measuring the wrong testpoints. If you don't have continuity then see if you can find a better schematic for your scope. If you have continuity between your test point and rectifier then I would remove the fuse from the circuit and measure voltage at your test point, and if so start tracing where that voltage could have come from.
Tektronix 576 HV transformer and other things - Page 1
Forum section: electronics / repair

author: bdunham7
author_rank: Super Contributor
timestamp: August 21, 2022, 08:23:43 pm
content: I recently picked up an older Tek 576 from Goodwill, looking pretty good but in unknown condition operationally. Got it home and didn't work, of course, and after some futzing with the power supplies it came to life for a short while. It has any number of smaller problems, but the main issue at the moment appears to be the known issue with the early HV transformer that supplies 225V and 4000V for the CRT. Apparently the issue is related to moisture absorption in the epoxy pour around the windings. The result is that as the transformer heats up, it 'leaks' and then the circuit draws more power which causes it to heat up more and then it runs away until the 100V supply that feeds the transformer oscillator cuts out. That is what happens here, as soon as the transformer gets up around 130F, the current draw rises. When cold, the circuit draws about 150mA minimum and about 210mA with the CRT as bright as you would ever want it. Once it gets warm, this increases rapidly until the 100V supply goes into protection at just under 300mA.My interim fix while I work on the other issues is to put a small fan on the transformer with the HV cover removed. This seems to work, I ran it yesterday for 8 hours straight with traces on the screen and the current stayed at 160mA the whole time. Perhaps adding a fan to the backside of the HV enclosure would be a fix.What I'd really like though is a replacement transformer. There's someone on tekscopes.io that had some made, but I haven't heard back as to whether he still has any. Has anyone come up with a replacement for this application? There is a bulletin and revision from Tek regarding a replacement that is NLA and requires some other mods. I'm hoping there is a solution other than me trying to custom-wind a 4000V+ transformer.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 22, 2022, 02:35:48 pm
content: Well, try again, he might be off on vacation. He was last active on tekscopes around the end of July. Maybe start a new thread there?He did a run of these back at the beginning of 2020 and they probably sold out. Unless you stumble across a NOS spare or get a used one, this was the only source of replacements I have ever seen.
Tektronix 576, no curve, endpoint only - Page 1
Forum section: electronics / repair

author: Ypsi
author_rank: Contributor
timestamp: July 23, 2019, 11:12:41 am
content: Hi friends!I picked up old curvetracer Tek 576 in very good optical condition, and with two holders, from scrap, nice buy, but he has extraordinary problem. During the test of DUT i see only endpoint of curve, no completely curve.... No effect by beam intensity knob, only the point is brighter...I think that step gener is OK, but i see corresponding points.. /switch 3steps, see 3 points.../Waveform on output of step amplifier OK.I hope that the CRT tube is OK.Attached the image of controls and CRT.Thanks for ideas and help.

author: hitecelec
author_rank: Regular Contributor
timestamp: July 23, 2019, 11:38:31 am
content: helloCould be just a setting . check the user manual first time operation Page 2-8 and follow the instructionsHope it helpsRegardsAnand

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 23, 2019, 11:46:55 am
content: Whoa Partner !What are you doing setting at 1500 Volts?And 200 volts per horizontal division?Drop it back to 15 volts.And lower Volts per Division Horizontal.If you have the switch turned to the diode?There will be no steps for Diode.Pins C and E only.Raise voltage from zero and the line will turn upwards at the drop voltage.The diode will turn on at .6 or .7 volts.You need to reverse the diode in the holder you have voltage flowing wrong direction.I got carried away with my first curve tracer also !!But there is a complete Operation and Service manual available online.Explains 1st time set-up.Diode should look like..Enjoy!Also from the looks of the screen your unit CRT is fine.I think I still have 6 curve tracers and none of them were free :-(

author: Ypsi
author_rank: Contributor
timestamp: July 23, 2019, 12:32:24 pm
content: Thanks for answers.I did the basic settings via user manual, at first place. When i do a connect the component /resistor, diode, or transistor/ it's all ok, but tek don't drawing continous curve, only endpoint, however the point runs on curve path... unfortunelly, no curve stay on CRT drawed.I have old hungarian curvetracer EMG, i have some experiences with CT, but Tek is rolls-royce against EMG ..I search further..

author: Johnny10
author_rank: Frequent Contributor
timestamp: July 23, 2019, 12:52:54 pm
content: Take everything off front DUT pad.Set to 15 VoltsSet horizontal to 1 voltTurn Voltage knob through range.You should see a straight line from one side of screen to the other.If not your voltage may not be changing.

author: Ypsi
author_rank: Contributor
timestamp: July 23, 2019, 02:19:44 pm
content: Ok, friends, everything is OK now. Founded leaked capacitor C829 on 100V powerline. 2280pF only.Now, the curves are back!Now i do only final check and adjustment.Thankyou!
Tektronix 577 curve tracer not working correctly - Page 1
Forum section: electronics / repair

author: lazza96
author_rank: Newbie
timestamp: October 12, 2024, 01:27:53 pm
content: Hi all,i bought a month ago a tek 577 with a few fixtures, since then i’ve tested it a few times and it was working but was a little out of spec, so i’ve dediced to do a little calibration and found out that 2 trimpots weren’t working (the R1245 and R528 ).Ordered some linear ones on digikey (the manufacturer is piher) and replaced the R1245 one. In the mA range everything is working fine but when i switch the vertical/div knob from mA to lower ranges the collector protection light turns on (and the beam on the crt gets greatly out of range), i don’t believe it was the R1245 that i’ve replaced, maybe the preamp in the 177 or the amp inside the 577? I don’t have much time testing all the components, as anyone had a similar experience?In addition, i see only now, that the 200 volt line on the power board is at around 218v…Thanks in advance

author: lazza96
author_rank: Newbie
timestamp: October 13, 2024, 08:23:03 am
content: I have a major update, today when i switch throught all the minor vertical/div settings the yellow light of overrange doesn’t light up, when switching by the 50 to 20 and 10 mA i’ve noticed a lot of noise on the trace, on the 5 (50 mA , 5mA and so on) scale seems better while the noise gets higher reaching the 1 (10mA,1 mA) scale, it gets so bad that the trace becomes a concave curve.Reaching the uA and nA side you can see a part of a vertical trace appear on the very top of the screen.Changing the Max peak or the series resistors doesn’t affect it.Thanks

author: hitecelec
author_rank: Regular Contributor
timestamp: October 15, 2024, 11:29:20 am
content: HiIf memory serves me right , There is a matched Dual FET in the 177 test fixture . Probably faulty.Try replacing, Try replacing , I think it has a Tek Part no 151-xxxx-xx

author: lazza96
author_rank: Newbie
timestamp: October 15, 2024, 01:59:45 pm
content: Yeah you’re right, i’ve just discovered it yesterda, the part is the Q604a/b is a dual n-type jfet, the Q604A side was faulty, the component installed in my 177 is the 2n5556 from siliconix, i’ll order one and release an update…Thanks for the help
Tektronix 577 D1 Horizontal gain and drift instability - Page 1
Forum section: electronics / repair

author: Kjo
author_rank: Regular Contributor
timestamp: July 16, 2023, 09:36:47 pm
content: This 577 is mostly working ok. All voltages are correct. I have cleaned most of the push buttons with DeOxIt but have not touched the covered cam switches. Tek manual says dont lubricate them.The vertical operation is working correct with no instability. But the horizontal zero point (and entire characteristic curves set) drifts L & R and sometimes off screen. Occasionally the horizontal scale factor randomly changes. Can those cam switches wear out? I am looking for pointers as to where to start.Update:I determined that the horizontal instability was related to the NORM/INV switch. The TC has spent most of its life in NORM mode (who uses PNP stuff.) In INV mode there is no instability! This switch has 3 DPDT that only reverse 3 sets of connections. Nothing is switched in or out of the H & V amps. Unfortunately the switch is on the back side of the amp board. Im not going to try removing it, and there is no clear way to get contact cleaner to it.I operated the switch 50-60 times and managed, for now, to clear what ever gunk was on the contacts in the NORM position. Interestingly, since the SW is locking IN for NORM, there are actually 2 parts of the NORM contacts that are used. The static position was gunked, but fully depressing the NORM switch and holding it uses a clean part of the contacts and the instability in horizontal went away.I have been able to complete most of the basic adjustments fine. But this is a D1 with storage that is not working. I know it did work many years ago. It is not critical that it works and I am not sure I understand the circuitry involved. Something for the future...Update:The future is now...I took some time to understand the flood gun storage schematic. I made a wild guess that complete lack of response might point to the cathode circuits. And sure enough, the heater bridge rectifier had some open diodes. Kluged up a bridge from 4 1N4002s and the storage system is up and running too.
Tektronix 577 D1 need photograph of foil side of storage circuit board - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: July 01, 2025, 10:53:12 pm
content: Because of a short, the bridge rectifier got hot and burned some traces on the storage circuit board on my Tektronix 577 D1.I have a photo of the component side as shown in the service manual but I need a photo of the foil side.I have the schematic of the circuit but it would be a whole lot easier for me to jumper the traces that are missing if I had the photo.Thank you.

author: madao
author_rank: Frequent Contributor
timestamp: July 02, 2025, 03:23:52 pm
content: A little tipp for you:Tektronix 5111 or 5103N D11 use same board

author: Bargainhunter
author_rank: Regular Contributor
timestamp: July 02, 2025, 08:00:29 pm
content: Oh No.I just gave a 5111 to recycling. I could have salvaged the board.Well anyway it looks like the bridge rectifier just connects to the filament winding and the heater of the crt to rectify the heater cirremt.Correct me if I'm wrong.Thanks for you input.

author: Testtech
author_rank: Regular Contributor
timestamp: July 02, 2025, 10:11:35 pm
content: It is for the flood gun heaters.
Tektronix 577 need help with transistor replacements - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: July 20, 2025, 05:01:23 pm
content: Could someone recommend replacements for the following transistors?151-0406-00 Transistor silicon PNP ST1264?151-0279-00 Transistor silicon NPN SS2821?These are from the deflection pc boardAlso need pinout for the CRT (storage version)Thank you very much

author: edavid
author_rank: Super Contributor
timestamp: July 20, 2025, 05:10:54 pm
content: Quote from: Bargainhunter on July 20, 2025, 05:01:23 pmThis is the place to look for specs:https://w140.com/tekwiki/wiki/Common_Design_Parts_Catalogshttps://w140.com/tekwiki/images/5/5e/Tektronix_Xref_sm.pdfQuoteIf it's not in the 577 manual, try the 5111/5111A or 603 manual:https://w140.com/tekwiki/wiki/5111https://w140.com/tekwiki/wiki/603

author: benj38
author_rank: Frequent Contributor
timestamp: July 21, 2025, 10:58:34 am
content: These are both relatively high voltage transistors, but nothing too special.151-0406-00 = 2N5401151-0279-00 = SE7056 (2N5058 should be a perfectly adequate substitute).
Tektronix 577 questions - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: March 29, 2025, 03:03:44 pm
content: I have a few questions.I received a Tektronix 577 D1 storage curve tracer without a CRT.Can anyone tell me the model number of a replacement CRT? Also is there a substitute? Where can I find one?The service manual lists 154-0634-00 and 154-0634-10 but I also read somewhere that it uses a 154-0633-10.Also does the D1 and D2 use the same CRT.Any help would be greatly appreciated.

author: loulou31
author_rank: Contributor
timestamp: March 29, 2025, 08:45:51 pm
content: Hi,No : D1 is storage and D2 is non storage ....For my opinion storage tube in good condition will be difficult to be found.RegardsJean-Louis

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: March 29, 2025, 10:43:29 pm
content: 154-0633-00 and 154-0633-10 non storage tubes can still be purchased for around $170-$200USD shipped. I ordered one and can comment further when it arrives. I’m not familiar enough with the D1/D2 circuitry to comment on compatibility issues you may find if you were to attempt a conversion.

author: edavid
author_rank: Super Contributor
timestamp: March 29, 2025, 11:50:18 pm
content: The display module for the 577D1 is the same as the 5000 series 5103N/D11 or 5111 storage module. You used to be able to get those cheaply since there wasn't much demand for a 2MHz mainframe.

author: Bargainhunter
author_rank: Regular Contributor
timestamp: April 03, 2025, 02:12:31 pm
content: Thank you for all your help.I think I found a used one.
Tektronix 6015 probe ground lead thickness of contact? *solved* - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: June 09, 2023, 05:37:34 am
content: Never mind, forgot to check ebay under generic terms. The specific part # was driving me nutsI am missing the ground lead contact. It looks like its a piece of 18AWG wire that is attached to some kind of bent metal piece.Any help with how thick the metal is, how it should be bent, and what it is made out of would help.I thought to use a piece of silver plated brass that is bent into like a slight bow kinda like the thing inside of a caliper. It presses up against the ground shield tube that the resistor is inside of. It is the dimensions a plastic keyway. Or is it just supposed to be strait and thick and wedge in there?
Tektronix 608 XY Monitor - extra trace mystery - Page 1
Forum section: electronics / repair

author: skeletonmeat
author_rank: Newbie
timestamp: April 11, 2024, 02:15:48 am
content: Hi all,Here with a mystery - I'm not the most experienced with this, so I hope I'm being dumb and it's an obvious fix!I have a Tek 608 XY Monitor that is mostly working normally, but has an additional static trace on the monitor (slightly off-center) at all times when powered on. The normal trace works correctly. The static trace responds to the Intensity and Z gain pots (although it's intensity is offset slightly higher than the normal trace), but not the X & Y offset pots, and its position is not affected by the input signal. The static trace is tied to the normal trace; i.e. when the trace is offset from the static trace by input signal or pot offsets the monitor will act a bit like a ramp is being input into X or Y.Hopefully this is more clear with pictures - these are a few of the display with the X&Y offset changed, but no input signal at all.Does anyone have any clues for what's going on here? My best guess is that the deflection amp is getting some kind of V constantly from somewhere, but I don't really know! If anyone has any pointers for repair, I'd really appreciate it! It's a nice monitor, and I'd love to get it working correctly.

author: CaptDon
author_rank: Super Contributor
timestamp: April 11, 2024, 01:00:47 pm
content: It would appear that perhaps you have an open filter capacitor on one of the supply rails producing a large A.C. voltage riding on top of a D.C. supply rail.

author: jonpaul
author_rank: Super Contributor
timestamp: April 11, 2024, 01:17:56 pm
content: damaged CRT?

author: skeletonmeat
author_rank: Newbie
timestamp: April 11, 2024, 05:58:07 pm
content: Quote from: CaptDon on April 11, 2024, 01:00:47 pmWhat would you recommend to troubleshoot this? I don't have a ton of experience with HV, but would it make sense to try and replace the large electrolytic caps on the supply board? I've repaired a scope before, but it was just some pretty obvious LV caps in the defraction amp section. I worry about this being over my head/slighty dangerous

author: skeletonmeat
author_rank: Newbie
timestamp: April 11, 2024, 06:01:39 pm
content: Quote from: jonpaul on April 11, 2024, 01:17:56 pmMaybe? I lean towards no because the extra tracelooksright? It isn't showing any crazy bloom or dead/burned spots
Tektronix 760A troubleshooting - Excessively large trace (solved) - Page 1
Forum section: electronics / repair

author: Smokescaped
author_rank: Newbie
timestamp: April 22, 2024, 02:29:44 am
content: Thanks everyone who helped with capacitor advice in the other thread, I successfully got the machine running.Bad news is the trace is enormous.Playing with the limit-screw adjustment for focus simply changes the sharpness of the 'trace' without changing its size.Once again I'm hoping for a helpful push in the right direction to begin troubleshooting this.Greatly appreciate any feedback. Cheers.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: April 23, 2024, 06:33:15 pm
content: reduce the intensity

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: April 23, 2024, 06:43:58 pm
content: On second thought this looks like a HV failure. First measure all voltage rails, make sure they're all fine.Measure voltage across C34 as well. Should be around +100v.Measure across R49. Should be 115v.Measure at pin 2 of J3, the voltage should vary between -15 and +100v depending on the setting of the astigmatism adjustment.Measure J11. Warning HV here. Report back.

author: Smokescaped
author_rank: Newbie
timestamp: May 02, 2024, 05:54:24 am
content: Thanks mate, reporting back!It's fixed and the problem was caused by bad resistors in the focus circuit.R3-R4-R5 were all significantly out of spec. I replaced R1 and R2 while I was there.
Tektronix 7623A Oscilloscope repair? - Page 1
Forum section: electronics / repair

author: Moogcat
author_rank: Newbie
timestamp: March 26, 2022, 11:35:57 am
content: Hello,I am wondering if anyone here can repair my Tektronix 7623A Oscilloscope?No green power up light and could be a recap issue...Thank you and I will supply more details if you are interested in the fix!

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 27, 2022, 10:47:37 pm
content: You might try the tektronix repair groups and let people know your area this is not a scope I knowand many times it helps to know what not to do first. I like the 400 upper end and the 2200, 2400 seriesand have much of the equipment to work on these.From Orlando Fl area.Jeff

author: sean0118
author_rank: Frequent Contributor
timestamp: March 28, 2022, 02:44:37 am
content: I'm in Australia, but here's the thread where I repaired my 7623A:https://www.eevblog.com/forum/repair/tektronix-7623a-oscilloscope-repair-log/

author: jonpaul
author_rank: Super Contributor
timestamp: March 28, 2022, 09:14:08 am
content: Bonjour,Suggest the tekscopes and tekscopes2 forums on groups.io, rather than EEV blog.https://groups.io/g/TekScopes2/topics7xxx TEK have linear PSU issues with power transistor and regulator socket pins, rectifiers and dry lytic caps, check PSU first.DL the serv manual at BAMA archives or TekWIKIBon chanceJon