hybridfree/eevblog-posts huggingface dataset:
Tektronix 2465 - Microprocessor's fault? - Page 1
Forum section: electronics / repair

author: Initial_Chris
author_rank: Newbie
timestamp: October 17, 2023, 05:23:33 pm
content: Hi everyone, this is my first time writing on this forum.A friend of mine gave me a Tektronix 2465 Oscilloscope that he had kept in his basement for years.I tried to turn it on but obviously the RIFA capacitors turned into a stink bomb.I changed all the RIFA capacitors (even the still healthy ones) and tried to turn it on again.When it was first turned on again it showed a narrow trace which could be controlled in height and brightness, but the oscilloscope showed no signs of life and the LEDs remained fully lit,I tried to turn it back on and from that moment the LEDs all light up for 1 second and then turn off. No trace is shown (other than some random noise for a few fractions of a second).No controls respond, not even the beam finder. The fan spins correctly.I checked the power supply voltages and they are all within range, including ripple. The only wrong voltage was +87V (which makes me worry that the U800 may have burned out), as it read +93V. I solved it by replacing U1281, Q1222, Q1223, Q1221.Unfortunately, even after fixing all the voltages, the oscilloscope still does not boot.Could it be the fault of the wrong +87V that has burned something that allows the oscilloscope to boot?Sorry for my EnglishEdit 1: I tried moving the jumper to "DIAG" and measured the entire address bus.All signals are "clean" square waves except D10 (Pin 19) which has a very high falling time.With the jumper in the normal position, while all pins are outputting data, D10 appears to float around 5V.I'm guessing it's the microprocessor's fault at this point. Can I replace it with any MC6802P?

author: Swake
author_rank: Frequent Contributor
timestamp: October 20, 2023, 07:36:29 pm
content: Have no experience with repairing this scope, but I would say yes to your question about it being possible to swap the CPU as it does not have any ROM and therefor is not programmed. Just make sure to replace with one running at the same frequency.That said, from your scope picture the pin is at 4V not 5V. That indeed does not sound correct.You named it D10, but it is A10, that is an address line.The CPU might be the issue, but also any other chip interfaced on that line.If the CPU is socketed, and thus easy to remove, you could try measuring the address lines with a multimeter in diode mode and resistance mode. Check for similar values between the address line and GND, Vcc and other address lines. If A10 is substantially different you have a good indicator.
Tektronix 2465 Options service manual - Page 1
Forum section: electronics / repair

author: bryonvp
author_rank: Newbie
timestamp: June 09, 2022, 01:00:20 am
content: Hi All,I hope I am not missing anything obvious, however I am searching for a service manual for the options boards for a 2465 cro. I have the 2465 manual, however doesn’t have anything for the other boards and cabling added to my unit.I have a badly flood damaged unit, which I have brought -mostly- back to life, though having trigger problems and a Test 05 Fail 42 startup error. The unit has options 05 and 10 which I want to temporarily disable and need the appropriate jumpering/cabling details from the option manual.Any help would be greatly appreciated!Thanks

author: bostonman
author_rank: Super Contributor
timestamp: June 09, 2022, 02:50:17 am
content: I have the service manual (which can be found online), but it's too large to post.Maybe I'm telling you something you already know, but those have a high failure rate on the U800 IC.Also, options listed in the manual are:Option 05 (TV) simplifies triggering and viewing of televisionsignals. The option adds TV (back-porch) clamp circuitryto the Channel 2 input and TV trigger couplingmodes, allowing selection of either horizontal or verticalsync pulses to obtain horizontal-line-sync or field-syncpulse triggering. This option permits triggering on aspecific line number within a TV field and provides syncpolarity switching for either sync-negative or sync- positivecomposite video signals.Option 10 allows the instrument to be remotely controlledand queried using a standard interface system. Theinterface implemented conforms to the specifications containedin IEEE Standard Digital Interface for ProgrammableInstrumentation (ANSI/IEEE Std 488-1978), commonlyreferred to as the General Purpose Interface Bus (GPIB). Italso complies with a Tektronix Standard relating to GPIBCodes, Formats, Conventions and Features.

author: picburner
author_rank: Frequent Contributor
timestamp: June 09, 2022, 03:14:53 am
content: The manual you are looking for is called 24X5A/2467 Options Service and you can find it on the ko4bb websitehere.
Tektronix 2465 repair - Page 1
Forum section: electronics / repair

author: Giovanni62
author_rank: Contributor
timestamp: February 16, 2020, 11:09:39 am
content: What should I check to try to repair it?Beam static and all LED lit onlong ago, I had already repaired it, replacing all the capacitors, but now I don't know where to start.

author: Giovanni62
author_rank: Contributor
timestamp: February 16, 2020, 09:18:21 pm
content: Could it be the A5 Control Board?

author: Giovanni62
author_rank: Contributor
timestamp: February 17, 2020, 07:09:23 am
content: Any suggestions are welcome.

author: TerminalJack505
author_rank: Super Contributor
timestamp: February 17, 2020, 07:25:34 am
content: You might want to attach any files to your posts so that people don't have to click your link. People are a little leery when it comes to clicking random links.

author: Giovanni62
author_rank: Contributor
timestamp: February 19, 2020, 06:33:44 am
content: Are not they random click!

author: tautech
author_rank: Super Contributor
timestamp: February 19, 2020, 06:45:05 am
content: The bible on all things 2465 is here:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/Jump in there and post a link to this thread if you like and you should get some assistance as many 2465 owners follow that thread.

author: Giovanni62
author_rank: Contributor
timestamp: February 22, 2020, 04:05:57 pm
content: Now it is 👌
Tektronix 2465A CT bootup test - Page 1
Forum section: electronics / repair

author: tonedeak99
author_rank: Contributor
timestamp: March 10, 2024, 01:56:07 am
content: Hi everyone. I have read the service manual and I'm not sure if I'm encountering a problem or not. The scope seems to boot fine with no error messages, but the light sequence it goes through is different than the one shown in this video:That video does one single cycle through CH1, CH2, CH3, CH4, ADD, INVERT and ends with the VERT light in the trigger section.My scope goes through CH1, CH2, CH3, CH4, ADD, INVERT. Then the GPIB lights for LOCK and REM blink once and it repeats CH1 (but blinks the TRIG'D light and blinks the CH4 light in the trigger section and then holds the CH1 light on the trigger section), CH2 (blinks the TRIG'D light as the CH1 light in the trigger section continues on), CH3 (blinks the TRIG'D light as the CH1 light in the trigger section continues on), CH4 (CH1 light in the trigger section continues on), ADD (CH1 light in the trigger section continues on), INVERT (blinks the TRIG'D light as the CH1 light in the trigger section continues on), CHOP'D (CH1 light in the trigger section continues on) and then completes with VERT in the trigger section and the scope goes to last known settings.Can someone tell me if there is any issue with my boot sequence?Thanks!

author: calibrationfixture
author_rank: Regular Contributor
timestamp: March 10, 2024, 08:44:32 am
content: Hi,Nothing to worry about. Deviations of a "normal" Boot Sequence are a result of installed Options and Firmware Versions.Calibrationfixture

author: tonedeak99
author_rank: Contributor
timestamp: March 10, 2024, 04:38:00 pm
content: Thank you for letting me know. According to the service manual a blinking A SWP TRIG’D light is a fault so I was worried.

author: jorgino
author_rank: Newbie
timestamp: June 24, 2024, 08:29:38 pm
content: I guess the 2465A CT has a slight different boot up sequence than the 2465A. Before I took mine apart to be recapped, I filmed it because of an issue I'm having with it, but you can see the boot up sequence here:https://youtu.be/TZBrt2rvHFA?si=84xBdbqrgiKqxjgDI hope this helps.Thanks,Jorgino

author: calibrationfixture
author_rank: Regular Contributor
timestamp: June 25, 2024, 08:13:25 am
content: Hi tonedeak99,Checked it today with a good Early 2465BCT (B016124). Boot-Up Sequence is the same as you described. Thus again nothing to worry about.Calibrationfixture
Tektronix 2465A DM TEST 76 FAIL 01 - Page 1
Forum section: electronics / repair

author: aa7ae
author_rank: Contributor
timestamp: January 26, 2019, 09:52:21 pm
content: The DMM in my Tektronix 2465A went out the other day and now the scope plays "Taps" with the fault message, "DM TEST 76 FAIL 01" displayed. I opened the scope and checked for loose connection and didn't find any. I also checked the internal and external fuse and that seemed fine. I took out the DMM board and checked the tantalum caps to see if any where shorted, but nothing there either. Does anyone else have some ideas of what might be going on here?

author: oventech
author_rank: Contributor
timestamp: January 27, 2019, 12:01:23 am
content: Hello. Found the Service Manual download page. Hope it helps.https://www.tek.com/manual/2465a-and-2467-service-manual

author: Monkeh
author_rank: Super Contributor
timestamp: January 27, 2019, 12:09:26 am
content: That manual doesn't cover the DMM option. This one does, though:https://archive.org/details/tektronix_2465_DMM

author: med6753
author_rank: Super Contributor
timestamp: January 27, 2019, 03:47:35 pm
content: This is from the 2465 DMM option service manual. I would assume the 2465A is the same.

author: MarkL
author_rank: Unknown
timestamp: January 27, 2019, 08:49:03 pm
content: Quote from: Monkeh on January 27, 2019, 12:09:26 amJust in case, here's the manual specifically for the 24x5A series options (GPIB, TV, CTT, WR, DMM):https://archive.org/download/tektronix_24x5aOptions_Jun87/24x5aOptions_Jun87.pdfThe explanation of the DMM error is still the same, but the DMM board assembly is a later rev (-07 vs -04) so there might be some circuit changes when you start digging into it.

author: kyhsc1815
author_rank: Newbie
timestamp: June 07, 2024, 12:38:22 am
content: same errora29 board t5210 transformer .pwr: isolaton hf pot corecomponent failure Where can I get it?same error like my Tektronix 2465dmm

author: calibrationfixture
author_rank: Regular Contributor
timestamp: June 08, 2024, 06:02:19 am
content: Hi kyhsc1815,Sometimes the Big (Inside) Fuse is the Fix:https://groups.io/g/TekScopes/topic/102589632#msg201824Calibrationfixture

author: kyhsc1815
author_rank: Newbie
timestamp: June 13, 2024, 10:43:18 am
content: I checked the fuse and it was blown.Even if I put in another fuse, it blew, so I checked again.c5112/c5111 short c5110 (no capacity) exchange (electrolytic low impedance)It's finally working. It took 3 years.
Tektronix 2465A DM - Page 1
Forum section: electronics / repair

author: stfjohn
author_rank: Regular Contributor
timestamp: October 06, 2023, 02:24:22 pm
content: Hello,Here we go again: when you turn on, the message "test 05 fail 24" appears (the following text appears in the service manual: "ADD main board - positive level not positive enough"). Can anyone help me?Thanks.

author: tggzzz
author_rank: Super Contributor
timestamp: October 06, 2023, 04:10:29 pm
content: For a good starting point, trythis.

author: stfjohn
author_rank: Regular Contributor
timestamp: October 07, 2023, 09:11:52 pm
content: Thanks,I tried to follow your advice, but, in no case, the problem relating to the error I reported is addressed, unfortunately....

author: med6753
author_rank: Super Contributor
timestamp: October 09, 2023, 01:40:16 pm
content: In section 9 of the 2465 manual there are error diagnostic flowcharts. I am assuming that the 2465A is similar. Would be worthwhile to check.Edit.....does that scope have the DMM option? If yes you may also need the 2465A Options Service Manual. Make sure it's for the "A" suffix and not the "no suffix" or "B" suffix. There are significant differences.

author: tggzzz
author_rank: Super Contributor
timestamp: October 09, 2023, 01:56:23 pm
content: Quote from: med6753 on October 09, 2023, 01:40:16 pmIt is the same, except the 2465A is p6-10.Either gurgle has become seriously crappier recently, or the OP's google-fu is deficient, or both. There are many manuals athttps://w140.com/tekwiki/wiki/2465A, and probably ko4bb and bama.
Tektronix 2465A... help did I blow it up?  - Page 1
Forum section: electronics / repair

author: GASMAN
author_rank: Newbie
timestamp: September 13, 2024, 05:52:54 pm
content: Hi All. New here to the forum. But not too new to electronics so I should have known better. I had my Tektronix 2465A connected to the antenna out put of my ham radio transmitter and began transmitting. Scope seemed to tolerate it for a while (sure had a nice wave form). After I realized what was going on I stopped transmitting. It happened a second time and now the 2465A is not so happy.On start up it gives me an error code of Test 05 Fail 24. I am not sure what that means -- . I can clear that code by pressing the A/B Menu button and the scope will continue to boot up. However; both Ch 1 and 2 fail to trigger on a simple 10mV 10kHx sine wave from my signal generator. Also when I switch scales the horizontal axis jumps way off scale. (Same thing happens on both Ch 1 & 2) .Did I totally fry the Scope... or is there hope. Thanks in advance for your help.Gasman

author: tggzzz
author_rank: Super Contributor
timestamp: September 13, 2024, 06:06:40 pm
content: Quote from: GASMAN on September 13, 2024, 05:52:54 pmDid it work before that happened?Was it in 50ohm or 1MHom mode?What voltage/wattage did you apply to the input?The service manual (available on TekWiki) defines the meaning of the test result. From memory (possibly faulty) I suspect you have a capacitor leakage on the A5 board. FFI see the other 2465 threads

author: GASMAN
author_rank: Newbie
timestamp: September 13, 2024, 06:26:02 pm
content: Thanks for the prompt reply.1. It was working fine before hand (and seemed to be working fine for a while afterwards so I thought I had escaped disaster and maybe the two events are unrelated)2. It was in 1 M ohm Mode3. I am sure at one point the output briefly hit 30 to 40 wattsAs I have never dug into the workings of the scope (although it sounds like I am about to) what is the A5 board. I was recapping an old transmitter and testing it out when all of this occurred. I will dig into the prior treads regarding the 2465A.

author: tggzzz
author_rank: Super Contributor
timestamp: September 13, 2024, 08:13:49 pm
content: So 40W into 50ohms is Vrms=sqrt(40*50)=44V. Vpeak is thus 63V (or 126V if it wasn't terminated in 50V). Ought to check that's OK at whatever frequency you were using. If course if you were using the scope to dissipate 40W in its internal 50ohm terminator, that might well be toast.Possible mistake of mine: ought to check if the 2465Ahas the problematic capacitors on the A5 board; it might be only the 2465B. Even if it is marked as a 2465B, you might care to check the A5 board, since apparently there's an infamous fleabay seller that <cough>upgrades</cough> 2445Bs. (I have a 2465, and that has neither the A5 problem nor the infamous Dallas battery-backed RAM).If the Dallas battery hasn't given up the ghost yet, you are lucky. It contains the calibration constants, and you don't want to lose those!You will probably want to recap the main PSU board sometime.Plenty of instructions to be found on gurgle. Many of those results are links to this forum.
Tektronix 2465A - How do I remove the fan impeller? - Page 1
Forum section: electronics / repair

author: aa7ae
author_rank: Contributor
timestamp: January 30, 2022, 12:35:20 am
content: I purchased this Tektronix 2465A DM from an E*BAY seller in 2015 who refurbished it. After a while, I developed a problem where the DMM no longer worked. I decided to crack it open and investigate. I discovered his work on the power supply was less than optimal. He only replaced a few capacitors, but not all of them. He also didn't replace the now cracking RIFA madness developing in here.How do I carefully remove this fan impeller properly? I don't want to break it, but it's not wanting to come off.I'll have to rebuild this power supply with all new caps and do it properly.

author: tggzzz
author_rank: Super Contributor
timestamp: January 30, 2022, 12:47:17 am
content: I presume you are following the instructions in the service manual.There are many descriptions of the process in this forum and the TekScopes group. IIRC the basic technique is to hold the but stationary with pliers, and use a screwdriver to undo the screw.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 30, 2022, 01:04:13 am
content: And after the screw is loose tap the screw toward the front of the acope. The screw is tighteng a conical collet.

author: aa7ae
author_rank: Contributor
timestamp: January 30, 2022, 01:25:30 am
content: The screw just broke! Great. Now I'm dead in the water. What a lousy design this is.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 30, 2022, 02:30:19 am
content: Hey, it worked for thirty plus years. Not all that terrible. And it left you enough of a nub to grab and get it out for easy replacement.I wonder if someone felt the need to put locktite on this screw at some point. It shouldn't have been that hard to turn.

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 30, 2022, 02:53:28 am
content: You broke it because you didn't read the manual on how to remove the fan assembly properly..You need to hold the shaft steady by using the slot in the screw, loosen the nut with a wrench, then give the end of the shaft a tap with the back of your screwdriver's handle, if you do it this way you will never break another collet.https://w140.com/tekwiki/images/8/8b/070-3831-00.pdfPage 6-25 has the official procedure.

author: tggzzz
author_rank: Super Contributor
timestamp: January 30, 2022, 09:26:33 am
content: Quote from: aa7ae on January 30, 2022, 01:25:30 amNo, you aren't dead in the water, but you do need to do some research and exercise some imagination.Yes, that part of the 24x5 range isn't particularly wonderful, but the other parts are.

author: tggzzz
author_rank: Super Contributor
timestamp: January 30, 2022, 09:28:34 am
content: Quote from: TERRA Operative on January 30, 2022, 02:53:28 amThat might not be entirely fair. I've used the "proper" procedure, and a collet still broke. As others have done, I simply made a replacement collet.
Tektronix 2465B Potentiometer Issues - Page 1
Forum section: electronics / repair

author: desswood
author_rank: Newbie
timestamp: June 21, 2024, 06:25:05 am
content: Folks,Just wondering if I can bother the '2465B Brain Trust'. Looking for a pointer as to shy none of the potentiometers on the from panel are working at all. When I perform Exercise 01 all of the buttons and LEDs display change vales on the screen but none of the potentiometers.Any starter for ten much appreciated..Dave

author: tautech
author_rank: Super Contributor
timestamp: June 22, 2024, 07:38:21 am
content: Welcome to the forum.Suggest you ask in the everything about 2465B thread:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/

author: desswood
author_rank: Newbie
timestamp: June 22, 2024, 01:34:47 pm
content: Many thanks

author: fmashockie
author_rank: Frequent Contributor
timestamp: June 24, 2024, 01:03:11 pm
content: You can also join the Groups.io group TekScopes. They talk nothing but Tek equipment and they are knowledgeable
Tektronix 2465B Scope Overall Low Voltage - Page 1
Forum section: electronics / repair

author: JE610
author_rank: Newbie
timestamp: September 29, 2019, 08:38:26 pm
content: Hi all,First post here. I recently came into possession of a Tektronix 2465B Scope (#B062849) and don't know anything really about it. I brought it home and when I powered it on all of the LEDs illuminated, a beam displays for a split second, and then both the LEDs and beam disappear. The lamp for the CRT stays on but it just flashes rapidly. After checking voltages at j119 it seems that all are low and out of range. I'm not sure what this would be attributed to and would appreciate a little insight and possibly thoughts on how to at least get it to a point where it will run its diagnostics. I've never really delved into something of this caliber so any information would help!Thanks!-J

author: tautech
author_rank: Super Contributor
timestamp: September 29, 2019, 08:44:24 pm
content: Welcome to the forum.Great resource for these scopes here:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/

author: Testtech
author_rank: Regular Contributor
timestamp: September 29, 2019, 10:24:56 pm
content: This model will virtually always need to have the PSU recapped. Resources here, and on Tekscopes@groups.io

author: med6753
author_rank: Super Contributor
timestamp: September 30, 2019, 12:33:48 am
content: Is the +10V reference correct? It should be no less than +9.9V and no greater than +10.1V. If it's off spec all the voltages at J119 will be incorrect.While your issue is most likely capacitor related there could be other issues. But a total re-cap of the PSU is a starting point. Details of performing the re-cap can be found here:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg1658102/#msg1658102

author: JE610
author_rank: Newbie
timestamp: September 30, 2019, 02:13:01 am
content: No, 10v ref is off by quite a bit. I want to say it was dropping to 9.52 at lowest. When testing voltages there was a noise like something shorting every so often as well. Just doing a quick visual inspection it doesn't look that any caps are leaking terribly. There doesn't seem to be corrosion or spots on the board indicating a leak. I can try and take a video of it powering on at some point.
Tektronix 2467BHD - Sloppy Clock / No data on display - Page 1
Forum section: electronics / repair

author: GroupB
author_rank: Newbie
timestamp: June 05, 2025, 03:51:51 pm
content: Good Day, All:Long, long, time lurkerI picked up a Tek 2467BHD (SN: B052007) a little while back because, well, always wanted one. I've had the usual fun with the A5 board and corrosion and replaced a bunch of the components, then recapped the power supply for good measure.As of now, I have a trace on the display, knobs work, etc....but no information (timebase, v/div, etc) is being displayed. I'm hunting though the machine trying to find where I either have a trashed component or a bad trace and, well, it's slow going. Today, though, found something that made me go "hmmmm.....huh?", and is beyond my knowledge.I was taking a look at U2830, and found that I had no 5mhz output, but the 10mhz clock looked crappy. Odd. So, I went upstream to R2649, and on one side, sure enough, it has the same crap waveform. But on the other side, we look good.I replaced R2469; same problem. U2830 was replaced as part of the corrosion repair. So, I'm left scratching my head: is the "square" wave that's feeding U2830 not clean enough for it to work with, and I'm losing my clock there. If that's the case, why is it that distorted, as there's not much in that circuit before I hit U2830?Thanks for any input you may have!-Chris

author: calibrationfixture
author_rank: Regular Contributor
timestamp: June 05, 2025, 07:01:58 pm
content: Hi GroupB,Read this:https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg5076121/#msg5076121Reply #1795Calibrationfixture

author: GroupB
author_rank: Newbie
timestamp: June 06, 2025, 08:59:15 pm
content: Hey Calibrationfixture:Thank you!....I noticed when I had U2890 of the board that the traces didn't seem to go where the SM said they would. Glad I wasn't dreaming that up.I checked my board; I have continuity between U2968 pin 8 and U2890 pins 9+10.Thank you for turning me on to that section of the much longer thread; I knew I was one in a long line of folks who have had fun with this and I have a few more things to check now, like R2890. Back to the bench.Cheers!
Tektronix 2711 Spectrum Analyser Lithium Battery Replacement - Page 1
Forum section: electronics / repair

author: Perenken
author_rank: Newbie
timestamp: November 17, 2023, 05:15:25 pm
content: Dear Colleagues, I am trying to replace the Lithium Manganese Dioxide Battery of the Tektronix 2711 and I can't find any spare part in the market, I have found out that its nominal voltage has to be 2.8V. Can you give me a solution? Thanks in advance.Julio Lopez

author: Testtech
author_rank: Regular Contributor
timestamp: November 18, 2023, 12:38:58 am
content: A standard lithium coin cell will work fine.

author: Perenken
author_rank: Newbie
timestamp: November 18, 2023, 06:14:16 pm
content: Thank you very much for the contribution, I found a Lithium battery from an HP Spectrum Analyser in my warehouse and by chance I gave it 3.0V and mounted it on the graphics board and the memory dump error that I was getting when starting the computer has disappeared.
Tektronix 2712 error - Page 1
Forum section: electronics / repair

author: z1zmail
author_rank: Newbie
timestamp: May 31, 2020, 12:23:37 pm
content: Good morning, I ask you for help for my Tektronix 2712. Everything seems to work, however, if from the Util menu I do the normalization I get the following error: Amplitude normalization failed, if I go into detail I have this error: BW FLTR AMPLTD (LIN) FailWhat can it depend on?I have option 12 installed. I have already replaced the 10uF 50V smd capacitors that I have found. ThanksFlavio

author: nanodocl
author_rank: Contributor
timestamp: September 09, 2022, 09:54:27 am
content: Sorry to resurrect this topic, but it's the only place I've found information about this. I have the same problem with a Tektronix 2710. I changed the lithium battery and check possible faulty SMD capacitors. Can somebody help on this. Were you able to solve this problem z1zmail?
Tektronix 2792 restoration - Page 1
Forum section: electronics / repair

author: Laval
author_rank: Regular Contributor
timestamp: December 10, 2023, 06:28:53 pm
content: Hello everyone.I acquired an old Tektronix 2792 spectrum analyser. It was very cheap. For what I can see, it works fine and measurements are accurate. I will have to run more tests and probably have it calibrated but for now I didn't want to let it work too long without working on the power supply first.So I want to change all the electrolytic capacitors on the power supply as well as the Rifa safety caps (X and Y class). I have a problem though, I can't figure out how to open the unit. There are those rubber feet on the top and the bottom with a screw in the middle but it doesn't seem like they allow the unit to open. At the back, there is those two big rubber feet with two big and long screws but once the screws are removed, the feet barely move at all. I didn't want to apply too much force to avoid breaking anything.I was wondering if anyone knows or have an idea how to crack this thing open.

author: tggzzz
author_rank: Super Contributor
timestamp: December 10, 2023, 06:45:24 pm
content: I've done similar things on my Tek 492A. If your SA is similar, Istrongly recommendgetting the full service manual, since dismantling it sufficiently toaccessthe PSU wascompletelynon-obvious.I got my 492 service manualsfrom ArtekMedia. Their quality is excellent and the price is sane. AFAIK, they are back in business after the critical person died.

author: Laval
author_rank: Regular Contributor
timestamp: December 10, 2023, 07:24:12 pm
content: Thank you for the answer. I looked on ArtekMedia and they don't have the 2792 manual but the 492 series look similar as far as the case is concerned. The most obvious difference I see is that the 492 don't have the keypad on the front panel so I ordered the manuals for the 492P. I didn't want a hardcopy so I chose the download but after the payment I didn't get any link or code to download. I contacted them and will proceed as soon as i get an answer.It seems easier to find information about the 492 series then the 2790 series, looks like they were not that popular.

author: KE5FX
author_rank: Super Contributor
timestamp: December 10, 2023, 08:52:26 pm
content: It'd be better to start with the 494AP manuals. 492 manuals are probably 10-15 years out of date.As for removing the cover, just pull harder.
Tektronix 370 Curve Tracer - How to adjust zero-point position? - Page 1
Forum section: electronics / repair

author: carl_lab
author_rank: Frequent Contributor
timestamp: August 13, 2017, 05:29:27 pm
content: Does anybody know, if zero-point position of AC, positive full-wave and negative full-wave collector supply modes can be adjusted individually?My problem is:If I adjust zero-point position using the front panel position trimmers let's say for AC, I have to correct position for positive or negative full-wave for a few millimeters to fit the graticule.I could imagine there maybe internal calibration to fix that problem.Can anybody help?Is there a service manual for 370 (not 370A or 370B)?

author: F1GWR
author_rank: Regular Contributor
timestamp: March 06, 2024, 08:36:24 pm
content: Hi Carl_labJust saw your post. Maybe it's too late but service manual of plain 370 is here:https://w140.com/tekwiki/images/c/ce/070-6065-01.pdf.Cal procedure is detailled there: p. 104 = 4-24.Especially it's not the polarity of the collector supply that must be used for that purpose but the CRT CAL rocker at the right of the Grat Illum pot.Best,Christian

author: electron1999
author_rank: Newbie
timestamp: January 05, 2025, 09:30:38 pm
content: Thanks ChristianYou saved me!
Tektronix 4051 screen filter / protector cracked - Page 1
Forum section: electronics / repair

author: Xenon
author_rank: Contributor
timestamp: September 19, 2021, 09:08:25 am
content: Hello all,Currently I am repairing a Tektronix 4051 for the Dutch Homecomputermuseum. It is in terrible condition and I hope I can get it working again.After powering it up (yes, checked the voltages first) I heard a klicking noise and smelled something burning. It appeared that a 5kV capacitor was arcing short (cracked). As soon as that is replaced I can test the rest.The green-ish filter in front of the tube is cracked. It seems like ordinary layered glass, but there is something special about it.On the back it has a metal coating on the top and bottom edge, and aluminum/aluminium tape at the corners. The pieces of tape push against springs connected to chassis ground.When held against the light you see a blue/red oily kind of glow on the back of the glass, like there is a special coating on it.Does anybody know if it can be replaced by ordinary green-ish glass, or does this coating have a special function for the tube to function properly? Or is it just shielding to protect the user from tube emissions?

author: David Hess
author_rank: Super Contributor
timestamp: September 19, 2021, 07:51:32 pm
content: My guess is that is EMI shielding. On many Tektronix instruments EMI shielding, which included a metal screen over the CRT, was an option.It it is not necessary for proper functioning so the CRT shield can be replaced with one that lacks the shielding.

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: September 20, 2021, 11:08:09 pm
content: Have a look under a magnifier to see if there is a mesh inside.

author: james_s
author_rank: Super Contributor
timestamp: September 21, 2021, 12:11:27 am
content: I'm only speculating but I would guess it's an anti-reflective coating to prevent a "hall of mirrors" effect from light reflecting off the glass and back off the face of the CRT. The EMI shielding is another good guess, it could even be both.I think plain glass or even acrylic would probably work fine, especially for museum duty. Certainly it would be better than the smashed glass.
Tektronix 453 High Voltage Transformer - Page 1
Forum section: electronics / repair

author: Douglasfir
author_rank: Newbie
timestamp: November 02, 2024, 09:07:57 pm
content: Hey guys, I'm in need of of a guide, or some assistance on rewinding a Tektronix 453 oscilloscopes high voltage transformer. Upon placing an ammeter across F937, and brining up the line voltage slowly, the current climbs fairly quickly to about 800mA where I shut the power off. I am told a properly operating circuit will draw somewhere around 2-300mA.A little background, Q937 was missing, (HV oscillator, equivalent to a 2n3055). F937 was open, When powering up slowly q937 gets far hotter than it should. Checked 500pf doorknob capacitor on the anode and it is not shorted. Power supply voltages (+12, +75, are within spec.) I have scoped the base of Q937, and the waveform is there, but it is heavily damped. This is at 20us, and running reduced line voltage (about 40VAC).I guess what i'm looking for here is someone that has a transformer they'd sell, or some guidance on rewinding mine. I have never rewound a coil of this size and it seems like a daunting task. Can anyone please help? Thanks so much!

author: Gyro
author_rank: Super Contributor
timestamp: November 02, 2024, 09:21:27 pm
content: Please don't double post, it annoys people who have already helped you... and the Mods.https://www.eevblog.com/forum/testgear/tektronix-453-high-voltage-transformer/

author: Douglasfir
author_rank: Newbie
timestamp: November 02, 2024, 09:33:34 pm
content: I am not double posting, I am looking for assistance in rewinding the transformer.

author: Gyro
author_rank: Super Contributor
timestamp: November 02, 2024, 09:39:51 pm
content: It relates to the same topic and the same transformer. Post the additional stuff that you listed above as a reply to the existing thread.

author: gnif
author_rank: Unknown
timestamp: November 02, 2024, 09:53:07 pm
content: Locked, do not double post like this please
Tektronix 453 - replacement screen filters and protectors - Page 1
Forum section: electronics / repair

author: Starfishzippo
author_rank: Newbie
timestamp: April 10, 2024, 05:54:23 am
content: I have just become the proud owner of a Tektronix 453 Oscilloscope which is in great condition but it lacks anything in front of the display screen. I doubt I could obtain a replacement screen protector or grey, green or clear filter but if anyone knows where I could get any one of these I'd be grateful.Alternatively I have heard of people making their own, does anyone have instructions or advice on materials and technique to do this in particular the frame that holds the filter and clicks into place over the display. The springs are present. Thanks!

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: April 10, 2024, 04:49:04 pm
content: I think any blue clear plastic would work just fine. Just have to get it to size and make sure it's transparent enough.

author: jonpaul
author_rank: Super Contributor
timestamp: April 10, 2024, 04:51:50 pm
content: In 1968, at my VERY FIRST job as an EE, the 454 was the first sold state scope and replaced the old TEK 500 series.453, 454 had a black mesh front filter for contrast and a metal filter was available for EMI.The P31 phosphor is best viewed with a blue filter plastic.You can get such from TAP plastics as a sheet and cut to size.The bezels and filter shrouds are perhaps on ebay or try the Vintage Tektronix museumJon

author: colorburst
author_rank: Regular Contributor
timestamp: April 10, 2024, 07:50:46 pm
content: Here is one idea, an acrylic sheet held in a frame made from bamboo flooring:https://groups.io/g/TekScopes/message/95727
Tektronix 465 - Page 1
Forum section: electronics / repair

author: heathkitman
author_rank: Contributor
timestamp: July 01, 2020, 01:16:19 am
content: Hello, I have a question about my Tektronix 465 oscilloscope. I hope this is the right place to post it. I’ve always loved the 465 and every hobbyist lab should have at least one analog scope. Mine works quite well except for the beam finder. When I press the beam finder button about ½ of the way down, there is a brief flash of a bold, horizontal line about 2 inches long and 3/16 high that then disappears completely. Looked at the schematic and it seems to be a rather simple circuit. Could it be as simply as a failure of switch S400? My other question is rather stupid. Most of the 465s that I’ve seen have a blue screen and a light blue trace, almost white. Mine has a decidedly green trace. I assume this is a function of the CRT that my unit has. Any thoughts?Thank you.

author: David Hess
author_rank: Super Contributor
timestamp: July 02, 2020, 02:03:12 am
content: Quote from: heathkitman on July 01, 2020, 01:16:19 amYes, that is a common fault. Cleaning and lubricating the switch will likely fix it.QuoteI have a couple of other Tektronix oscilloscopes with the same differences. Despite having the same nominal CRTs or phosphors, some have a decidedly greener trace and some are bluer and whiter. My guess is that there was some variation in the processing and application of the common P31 phosphor.
Tektronix 465 CH2 issues - Page 1
Forum section: electronics / repair

author: Microgiant
author_rank: Newbie
timestamp: September 14, 2020, 06:22:08 pm
content: Can someone please point me in the right direction?I am repairing a Tek 465 that had several problems. So far I have rebuilt the power supply with all new capacitors, a new bridge rectifier and 3 new transistors. All voltages are now as expected with low ripple. I then repaired an issue with A trigger not working.Now I am am stumped by an issue with channel 2 vertical. I assume its a vertical issue because its missing about 50% of its amplitude and the square wave is ramping. I initially assumed it had to be part of these circuits since the problem is only on channel 2 however I can find zero issues on the Vertical Preamp board or Vertical Switching. Its originating somewhere else.Someone has attempted repairs on the scope before me and they were ham fisted. The delay line was roughed up and had to be soldered to the vertical preamp board. I cleaned this up the best I could and Im not sure if it had anything to do with my problem, I dont see how it could affect anything.https://groups.io/g/TekScopes/photo/253550/0?p=Created,,,20,2,0,0I will cross post to the TekScopes group to get some other eyes on it as well.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: September 14, 2020, 09:01:18 pm
content: Usually these problems in many scopes are in the input. In this scope the attenuator is a likely suspectI do not know if you checked this specifically.Wally

author: Microgiant
author_rank: Newbie
timestamp: September 14, 2020, 10:53:21 pm
content: The only attenuators I am aware of are located on the vertical preamp right after the BNC inputs. I have tested the complete vertical preamp including all inputs and found nothing wrong.After testing the vertical preamp board and switches and finding nothing wrong, I was confused so I second guessed myself. I thought I must of missed something so I took a second working vertical preamp board complete with attenuators and vertical switches and swapped them and the problem was exactly the same.

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2020, 12:06:49 am
content: Half amplitude on one channel only usually means that there is an open along the differential signal path up to the vertical channel switch.

author: Microgiant
author_rank: Newbie
timestamp: September 15, 2020, 03:51:01 am
content: Hi, Yes, thank you, it turned out the "open" was one of the two AC/GND/DC leaf switches. Here is the thread that solved the issue.https://groups.io/g/TekScopes/topic/76848756?
Tektronix 465 no horizontal sweep - Page 1
Forum section: electronics / repair

author: Crambone
author_rank: Frequent Contributor
timestamp: December 22, 2021, 01:32:36 pm
content: I received a 465 that didn’t power on and found the Tantalum Cap in the HV section was shorted, I replaced and it now powers ON. While opened up I replaced all the electrolytic caps except the ones that are matched. I cleaned all switches and contact per some videos ie seen on how too do it properly, I used MG Alcohol so no residue would be left behind. The scope shows a nice crisp Dot and I can move fully vertical and horizontal with the controls. Im NOT seeing any Horizontal Sweep, I do see Vertical if I hook a probe up and touch the end with my finger. As I'm just learning electronics as a retirement hobby I’m no tech but willing to listen and learn. I see correct voltages on all the Test Points and was shocked actually how almost dead on they are. I was told elsewhere to check Q1224 for signal. Now I checked it for voltage and I’m seeing:C 3.134VdcB nothing no signal on digital scope -2.20mVE -0.674 vdcIf I hook my Rigol DS1104Z to the center Base I’m not seeing anything, assuming it will pick up the Cigna in Auto?I did find by mistake the A trigger switched wired wrong I believe as I was seeing 55vdc on the black wire coming off. I’ve attached a picture of what it looks like now with another yellow arrow showing where it was attached. I’m wondering if this black was a ground and feeding 55vdc if it could have caused this Horizontal Sweep issue? Possible it took something out?I’m at your Mercy and looking for advice and where to start?

author: Crambone
author_rank: Frequent Contributor
timestamp: December 22, 2021, 08:10:42 pm
content: Video of issue I’m seeing:https://youtu.be/uVUMY11D8t8

author: med6753
author_rank: Super Contributor
timestamp: December 24, 2021, 07:56:15 am
content: If there is no sweep signal at Q1224 as per TP78 in the manual then the issue is in the sweep logic further back. The manual gives excellent test points of the expected signals which your DSO should easily monitor.If you don't have a decent copy of the manual go to Artek Manuals and order one. Make sure it's for the 465 and NOT the 465B. The nice thing about the Artek copies is that they are fully indexed, clear, and are complete.

author: james_s
author_rank: Super Contributor
timestamp: December 24, 2021, 08:05:41 am
content: Stupid question, but are you sure it's not in XY mode? I've seen "broken" scopes sold cheap because of that in the past.

author: Chris56000
author_rank: Frequent Contributor
timestamp: December 29, 2021, 08:01:50 pm
content: Hi!I should add that unfortunately, I bought a 465B EARLY manual from Artek (070-2757-00) and unfortunately it was not up to their usual advertised quality standards, as some of the foldout pages were scanned in sections, the manual circuits were full of hand scribbled notes, crossings–out and blotches!(I have contacted Dave about this!)Chris Williams
Tektronix 465 no trace - Page 1
Forum section: electronics / repair

author: Feyman_Follower
author_rank: Contributor
timestamp: October 07, 2022, 06:26:09 pm
content: Hello I bought today this oscilloscope: it is in good condition, display illumination lights up also if it is a little flickering, every indicator light turns on, the only big problem is the CRT: it looks completely dead, it shows nothing. I measured the voltages and they are all lower than expected: +15V +11.27V; +8V +5.76V; -8V -6.23V; +5V +4.14V. Another problem is the fan, it doesn't work. Instead the fuse isn't blown. Can someone help me?

author: mzacharias
author_rank: Frequent Contributor
timestamp: October 07, 2022, 07:41:01 pm
content: I'm no expert on the 465, but I have seen an open, even intermittent, bridge rectifier.Rather than pulling out the board for service, it's possible to wiggle the rectifier until the leads break, then clear the holes and solder in the replacement.

author: med6753
author_rank: Super Contributor
timestamp: October 11, 2022, 04:44:11 am
content: All of those PSU voltages are referenced to the +55V source. If that voltage is low then the entire PSU will be low. Check the +55V and repair as required.
Tektronix 465 Oscilloscope - Page 1
Forum section: electronics / repair

author: j@cs
author_rank: Newbie
timestamp: November 04, 2017, 09:38:33 pm
content: Hi, I have recently buy a 465 in good conditions but it`s front panel is quite a bit dirty. When I tried to remove the buttons to clear it, I couldn`t remove the delay time button and also that one that you have to pull to limit the bandwidth.The delay time button is a bit complex and I`m afraid to damage it without any tips. And regarding to the BW limit button I`m afraid to pull it hard and break something. Does anyone there can give me some tips or even post some photos, if there are any, to help me?Thanks guys.

author: ebclr
author_rank: Super Contributor
timestamp: November 04, 2017, 10:09:35 pm
content: http://download.tek.com/manual/070940300.pdf

author: j@cs
author_rank: Newbie
timestamp: November 12, 2017, 07:34:56 pm
content: ebclr, thanks for sharing the manual. Actually my oscilloscope is the Tektronix 465. Not the TAS 465. I am attaching a image it`s front panel.

author: rhb
author_rank: Super Contributor
timestamp: November 16, 2017, 12:51:28 am
content: Look here:http://bama.edebris.com/manuals/tek/465/

author: j@cs
author_rank: Newbie
timestamp: November 16, 2017, 09:36:55 pm
content: Thanks for the tip rhb.I visited the link and downloaded the manual. But it is incomplete and didn't show how to disassemble the front panel.

author: bd139
author_rank: Super Contributor
timestamp: November 16, 2017, 09:47:27 pm
content: I’ve done a few of these. To remove the delay time knob, there is a grub screw on the top half of the knob. Undo that. It will slide off. Under that is the main body of the vernier control. You need some long needle nose pliers to unscrew the big ring around the shaft. Whole thing will come off the front panel then. Watch out because the pot can fall inside the case. The rest of the controls are straightforward.Don’t take the buttons off if you can help it. The shafts break easily. Just push in, clean, pull out, clean. Contacts for the bandwidth limit are at the opposite end of the scope to the button to give you an idea how complicated they are to get out!The bulb indicator shafts pull out and can just be pushed back in after.

author: rhb
author_rank: Super Contributor
timestamp: November 17, 2017, 03:17:57 pm
content: I looked at my original manual and there's very little discussion about disassembly. No mention at all about the front panel.

author: m3vuv
author_rank: Super Contributor
timestamp: November 29, 2021, 01:35:38 am
content: sorted,i didnt see the slot in the outer where it unscrews,used a pair of circlip pliers on it,came undone easy.
Tektronix 465 - Vertical Deflection - Page 1
Forum section: electronics / repair

author: kc4i
author_rank: Newbie
timestamp: August 20, 2024, 09:53:12 pm
content: Hello Forum.I have a Tektronix 465 which I want to fix. I have been using it almost daily since 1998. Several weeks ago I powered it on and the vertical deflection was gone. If I press the beam finder, a horizontal trace will appear on screen, about a quarter inch above center. The up-down adjustment will not bring that trace into the visible area of the screen.Any advice that would help in diagnosing and repairing this problem would be appreciated very much. Thanks in advance.Henry

author: andrewtaylor
author_rank: Contributor
timestamp: August 21, 2024, 08:26:59 am
content: I recommend the 465 service manual with the "fault search tree diagramm".If you have this,the very first step is to check ALL voltages on the main PCB (+50V. +15, -15V. 8V etc.) --- with the age of the scope, it's the point to start with

author: bborisov567
author_rank: Regular Contributor
timestamp: August 21, 2024, 11:43:03 am
content: You can take a look at that video:It is for 475 but i believe it might be helpful. Also if you have a transistor tester i would strongly recommend checking the transistors around the vertical deflection circuit. You can also find the service manual at the Tekwiki.

author: kc4i
author_rank: Newbie
timestamp: August 23, 2024, 07:14:48 pm
content: Mr. Taylor and Mr. Borisov,Thank you kindly for the advice. I will pursue those ideas and see where it goes. I appreciate your knowledge and help very much.Henry Fisher