Hi, I just picked up an OT502 E/O Converter TM500 Module in a mainframe of assorted modules, and am looking for a user/service manual for it. There doesn't seem to be much online.. If anyone has a copy, paper or digital, please let me know! Thanks, Jared

I am having a problem with my Tek 453 scope, SN 001688, Mod 210H made for IBM. The display is very wide vertically and very bright - I have no control of the intensity. The Focus control does work. I used a Fluke 75 DVM for voltage measurements and a Owon VSD2200I PC oscilloscope with a laptop computer for waveform measurements. All the power supply voltages are within tolerance using a Fluke 75 DVM. Unfortunately I do not have a meter capable of reading the negative 1950 cathode voltage. On the Z Axis Amplifier I am able to vary the voltage at TP 1047 from 2.6 volts to 80 volts using Intensity control R1005, however it does not affect the very bright sweep intensity. The negative going gate signal looks normal. On page 38 of the Tektronix manual “Troubleshooting Your Oscilloscope”, paragraph 1 states: Inability to turn off the intensity is often caused by a weak D.C. Restorer diode in the control-grid supply. I assume they are referring to diode D940 in the CRT circuit. I disconnected one lead of one of the 2 diodes in series (PN 152-0408-00) and using a 9 volt battery and my DVM in series with the diodes I measured the forward and reverse voltage. For D940-1 I measured 5.552 volts in the forward direction and 0.039 volts in the reverse direction. For D940-2 I measured 6.230 volts in the forward direction and 0.105 volts in the reverse direction. Are these voltages normal? Speaking of the CRT circuit, where are the vacuum tubes and the majority of the resistors located? Are they behind the CRT circuit chassis and if so must I disconnect anything to access them? Even though the troubleshooting manual states internal CRT grid shorts may not show up with ohmmeter resistance checks, I went ahead and unplugged the socket from the CRT and checked for continuity between pins. Everything checked open. I would very much appreciate any help identifying and solving the source of this problem. Thank you in advance.

I have a 1780R I want the Dallas chip(s) replaced with new chips like ones that can be done on a 2465B (fram/Ramtron/etc.). I do not have a reader or capacity to make the surface mount chip and board with pins to plug in the original socket. Who here will do this? I can send the chip/board(s) to be replaced. Thanks. Mark

Hi I'm currently trying to make some remote measurements (via USB) on a pair of repetitive waveforms using a Tek MSO4104. They occur about once a second and I want to measure the time interval between them (CH1 to CH3). This is easy to do manually and then read the data off the screen, but I want to do it many thousands of times during an extended test and log the results and I don't want to miss any events. So I need to do this via USB or GPIB. I'm currently using USB and I can control the scope remotely just fine over USB for most commands. However, I'm struggling to get this measurement process to work properly when doing it remotely. This initially appeared to be a simple task, but I can't work out how to ask the scope to make a measurement at the relevant time and to then report it back to my PC via USB. I assume I have to use the *OPC or BUSY or *WAI commands and let the PC wait for the scope to spit out the measurement data. I've set a suitably long timeout. I've tried normal trigger mode and single shot. Has anyone done this kind of thing before? I assume I either have to poll the event status register or find some way of getting the scope to time everything and then spit out the result via USB. Thanks in advance for any replies :)

The vintageTEK museum has completed their 2025 calendar and is offering it for sale at the museum, on eBay, and on the Lulu bookstore. The museum is a 501C3 non-profit educational museum whose mission is to encourage the next generation of engineer and scientist through preserving the history of Tektronix, those that created the legacy, and by supporting STEM in the local community. We do not charge for the museum or our STEM efforts and operate 100% through volunteers, donations, and by sales of items such as the calendar. This year's calendar commemorates the 60th anniversary of the Tektronix 1965 calendar. The pictures and descriptions for each month are from the 1965 publication. The pictures are of hand paintings by Portland artist Paget Loomis for the 1965 calendar. Each month has notable historic dates indicated while the front and back covers feature the vintageTEK museum. There are links and sample pages at https://vintagetek.org/2025-calendar/

Can someone who knows about troubleshooting the SC502 please take a look at my 8 second screen capture video and offer opinions / suggestions. This is the same SC505 I was working on a year ago! https://www.icloud.com/iclouddrive/0e1d2eLyaj24xXMvT7YU9SOkQ#Video Thanks!

Has please someone the 3.1 firmware (EPROM images)? Thanks

Does any one or any place have comprehensive information on these two subjects 1: light filters 2: implosion shields "manufactured" by Tektronix? I need engineering diagrams and or samples of no longer available parts. -- Jeffeelcr

Hi there, i recently found a free tektronix 7704A Oscilloscope, but unfortunately it isn't working properly. When i power it up the only thing that shows up is a very bright (so bright i suspect it would damage the phosphor if i left it on too long) Spot, which only changes shape with the Focus and Astig Controls. All other controls do nothing and it's the same regardless of whether the acquisition modules are installed. Does anyone have any suggestions for what to look at? I'd love to get this thing working! Here's a photo of what i'm seeing: https://groups.io/g/TekScopes/album?id=299173

Hi, this is my first post to the forum. Thanks for having me. I have a 465M that has recently started to blow its mains fuse (250V/500mA fast blow). The scope was not in use for several years before I started using it, and it has been working ok for the couple of months I have been using it. There was no event associated with the fuse blowing; I was using it in the morning, and when I came back to use it in the afternoon, it would not come on. I subsequently found the mains fuse blown. I only have a digital multimeter to do trouble shooting with (it does not have a capacitance or ESR function). In terms of trouble shooting, so far I have: * Removed the horizontal and vertical modules, and determined the fuse still blows with them removed (I turned the monitor intensity way down, and powered on only for a moment), so the issue seems to be on the main board. * Tested the transformer winding resistances (secondaries out of circuit). Yellow secondary pair measure 4.3 ohms; brown/blue pair measure 0.7 ohms, and 0.3 ohms each side to the centre tap; primary winding measures about 57 ohms. Neither primary nor yellow secondary windings have any continuity to ground. Do those readings check out? * Pulled both bridge rectifiers associated with the secondary windings and tested out of circuit. Both test good. * Tested all diodes, transistors and capacitors on the main board for obvious shorts (in circuit). No shorts found (although I'm aware the caps can't properly be tested this way, except for dead shorts). * Visually inspected for problems. No burnt components or other obvious signs of failure present. The exception to this point being a ring of brown residue (electrolyte?) at the bottom of one of the main filter caps (18,000uF), and a possible slight bulge in the 1000uF filter cap. I have included a pic of the 18,000uF cap in question in the photos section. The other thing possibly worth mentioning is that having perused numerous Tek threads, I notice similar (healthy) scopes have a slightly sharper, thinner trace than mine did before failing. I never thought anything of it as it naively looked good to me, this being my first scope. Have I missed checking something obvious that could be blowing the mains fuse? At this point I feel I've checked the main culprits, apart from the filter caps, which I can't assess properly with my multimeter anyway. Should I just go ahead and change the filter caps, and see if that remedies the issue? Thank you Nick [https://s-install.avcdn.net/ipm/preview/icons/icon-envelope-tick-green-avg-v1.png]<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free.www.avg.com<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>

The HV on my 5116 won't oscillate, (never has) hence no HV. + / - 30 V & 5V all OK, +200 is a bit high at +215V Been round the test points in the manual - nada. (no drive to the oscillator transistor Q252 ? Checked good with Peak tester ) Voltages on Q252 are + / - 40V instead of + / - 38V I am working my way through the article in Tekscope 11/72 which applies to the 5100 series, but the 5116 HV seems very similar, apart from the CRT heater voltage being derived from a winding on the HV transformer, not the mains transfmr. Is it likely that the HV transformer has shorted ? Part 120-1466-00. Maybe specific to 5116 because of the CRT heater winding. What am I missing ? many thanks Tim --

Hi guys, there is a used 7934 on eBay without plug-ins. The photo shows the screen that is unevenly lit and I wonder if it is normal behavior. I already have some dead scopes and I am not thrilled to get another one dead beast. The price is acceptable but I am not sure if it is normal to get such picture on the screen without plugins. Thank you for the answer. The link is here: https://www.ebay.co.uk/itm/135393506411?mkevt=1&mkpid=0&emsid=e11051.m43.l1123&mkcid=7&ch=osgood&euid=24ceaf637c964a0e92bf211fc7805618&bu=44912724721&osub=-1%7E1&crd=20241128020253&segname=11051 If somebody decides to get it instead of me, no hard feelings. I have the collection of 11 scopes and I wouldn't cry if I miss this one. With kind regards, Josip Luetich, Croatia

Anyone know what scope this is? I don't think I've ever seen one like it and zooming in to see a possible model number isn't working well: https://www.ebay.com/itm/283968232198 Thanks, Barry - N4BUQ

Hi Group, I'm looking for the schematic and parts list for late rev S1's, (and possibly S2's), where the strobe board was simplified by eliminating the snap-off diode, and the sampler diodes were Schottkys. My S1 is #B094100 and has a simplified strobe board like this, marked 388-0948-01. I'm interested in possible part number changes to the avalanche transistor, Q69, and to the values of the R's and C's in the sampler network, with a view toward successfully using modern Schottkys in older samplers. I've had no luck with TekWiki 140, BAMA, and manuals.lib. Any help is appreciated. Karl Goedecke

Dear All, I bought a 11302 oscilloscope which regularly fails the Enhanced Accuracy (two times however it completed it successfully, maybe in 50 attempts). The error is always "Mainframe amplifier calibration failed". The extended self test is always passed positively and for the rest it seems to work well, even if the buttons on the screen are not perfectly aligned in the graticule. I got the TekCATS software, an old DOS PC and could successfully connect to the 11302. Perhaps, if I could perform the alignments prescribed for this error I could fix the gear, but many of them require one or two signal standardizers which I don't have (Tektronix part 067-0587-02 o 067-0587-10). Has someone any suggestion? Thank you with all my heart for any help Gianni

Hi, I'm continuing the troubleshooting of the TDS 640 from where Halden left off in Troubleshooting 11 DRAM Processor/Display board in TDS640, https://groups.io/g/TekScopes/topic/106471282#msg205492. A summary of my continuation follows. I've checked, all of the low voltage supplies +/-5, +/-15, and +25, on A11 Dram/Processor/Display module. They are all within specification. Halden had replaced the capacitors on the A11 Dram/Processor/Display module, but not on the other modules, as far as I can tell. The scope, originally displayed flashing .8, as Halden had experienced, with switch pack s1001 set in the default (closed position), but after I ran through all of the tests using the 8 position switches set to run individual tests and then setting all 8 switches to the default setting, it now stops at 7 (solid, no dot), When selecting test 7 (switches set to 11000111) the display shows .E (solid). This error in the documentation is shown to be Write Bus Control (open). The other individual tests run by themselves, by selecting the appropriate switch settings, as far as I can tell run without error (no .E). I have ordered an Option 13 module as this scope does not have one, as I understand that will allow me to see an expanded errorlog. It will probably be showing up in a week or so. What else can I do, besides getting a hold of an A11 Dram/Processor/Display module, (as called out by the service manual)? General questions: When the Option 13 module and cable arrive, I'm assuming it will be a functioning module, I just connect it to the correct header, set the s10001 switch to "expand errorlog and increase diag messages", run Hyperterm on my computer, connect it to the scope RS232 port, figure out whether it is a modem or null modem connection set baud rate, (9600?) stop bits (none?), and parity (none?), and it should work. I have downloaded the TDS520B Component Service Manual, and TDS 544 Detailed Service Manual, the available TDS 640 manuals I could find on Tekwiki. What am I missing? I understand detailed troubleshooting manuals for the TDS 640 are not available. Thanks ov

I’ve been using this 7904A oscilloscope for a few decades, but my wife has finally convinced me to downsize, so I’m looking for someone who will give it the care and respect it deserves. It’s a unique scope, having been a part of Mildred Dresselhaus’s lab at MIT, where she did pioneering carbon research. The lab decided to get rid of the scope in the early 2000s in the traditional manner: covering it in “decomissioned” stickers and putting it in the hallway for crufters to claim. It still has the accompanying DRSLHS-stenciled cart, whose wheels work perfectly well, a little surprising given the age. The scope itself works fine as I can tell, as of six months ago. The main damage is my cats have bitten some of the knobs, and one is slightly bent. Please let me know if there’s any interest in this. I’m in San Francisco and would prefer pickups. https://groups.io/g/TekScopes/album?id=299063

https://www.ebay.com/itm/166747770124?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=CTI57OxBQDq&sssrc=2051273&ssuid=CTI57OxBQDq&var=&widget_ver=artemis&media=COPY Brief Description: I am selling a pair of matte grey 3D printed Tektronix cable holders that fit Tektronix 22xx series scopes, ei: 2201, 2205, 2210, 2211, 2212, 2213, 2214, 2220, 2225, 2230, 2235, 2236, etc... It will NOT fit the following 22xx series scopes: 2245, 2246, 2247, 2252 A non 22xx series scope that fits this part would be the 2815. 3D printed with matte grey PLA plastic. New option available: Black option is now Available. See image 1 for an example of the matte grey part, but imagine it black. The matte grey part is a newer and more revised design. Contact me for inquiry. Screws will not be supplied. You will need 31mm long 6-32 machine screws. 31mm as the length from the underside of the screw head to the very end of the thread. Here is a file format for those of you who have 3D printers: https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg5161746/#msg5161746

Hi all. So, I have this dead 2445B (There are two images of the A3 schematic and board layout in the Photos section). ...It appears to me that the Line Rectification section is fine, so going from the schematic at the start of the circuitry, the first test voltage is +264v. My initial measurement was 0.07v. Looking at the schematic, there is a FET Q1050, shortly after this voltage test point. Immediately after that FET is R1052 which connects (or isolates) the rest of the pre-regulator circuit. Lifting one leg of R1052 raises the +264v test point to +258v I've tested the transistors, zener diodes and various other components but nothing is shorted. Does anyone have any ideas as to where to look next? James

Hello all: Am Seeking a Tektronix scope 7904A service manual, Original printed version The usual online, PDF , Artech repro etc are not suitable. For museum use, by non profit. Location in USA, (or France) we can arrange for shipping.... Open to offers, or swaps, have a LOT of TEK/HP/GenRad manulas and some TEK origial probes.... Please send a PM if you have one to spare... MANY THANKS Jon