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Hello I recently picked up a 453. When triggered on a sine wave it seems to flicker. Interestingly it will stop flickering when i reduce the time to a certain point. Wondering if someone can point me in the right direction. Attached is a video of the 453 flickering. https://youtube.com/shorts/5bO2awzeM_0?si=C69KyYX0dRHl2lhW

HI Teksperts I have the chance of getting my hands on a TDS684A with a discoloured screen and suspect that it mat be suffering from the degradation of the 'gel' between the CRT and LCD 'shutter'? I have discovered that there is a modification to replace the CRT and shutter with a backlight LCD panel. Has anyone any experience doing this successfully and any pointers to the technique. Secondly whilst scouring the web for this repair information, I also noticed that quite a few of these series of 'scopes can be 'hacked' to unleash the full power of the instrument. i.e. faster and deeper memory etc. (throttled back at the factory) Are there hacks for the TDS684A in a similar vain? Finally the TDS684a is sometimes listed as a 500MHz machine and in other places a 1GHz instrument. So.... What frequency will the instrument faithfully reproduce on screen please? Thanks in anticipation Dave

I completed the design yesterday and started making the replacement rear feet for Tektronix 465, 465B, 466, 468, 475 and 475A Oscilloscopes. These feet are replicates of the original very hard rubber feet used by Tektronix. The original feet tend to get very brittle with age and break easily. I manufacture replacement feet using ABS plastic and a 3D printer. ABS is very strong. It is also more rigid than the original material. I took the material into consideration when designing these feet, ensuring the power cord appropriately "snaps" in place as it wraps around them. I uploaded additional pictures in the Photos section under "3D Printed Parts." All feet will be printed in black. However, other colors are available if desired. Please contact me if you would like to purchase new feet for your scope. Thank you, Tim

Hi, I'm in Toronto Canada but would probably pay a reasonable price plus shipping from anywhere, if someone has a spare or parted out intact plastic bezel for a Tektronix 606 XY. One of mine took a hard knock at some point and got smashed in a corner... Thanks, --Toby

Hi All Have two issues with my Tek 2246 scope display. Looking for common faults before digging in. 1) Display brightness fades after approx half hour after power on. Display geometry is fine, it just dims 2) Display seems to have a slight flicker . . . it's also noticeable on the green LED's illuminating buttons Bought it in not working condition. Replaced rectifier in -15VDC supply. All now working well except these two issues. All other supply voltages look steady, although have not taken time to look at any ripple/abnormalities. Thanks in advance, Mike

I'll try to keep this brief, but this is an end to end diagnosis and repair description. Maybe this will help someone in the future who has a 465B or similar scope with a similar problem? Experienced techs will laugh at my ignorance, a chuckle which I both accept and invite. :-) This post concerns the diagnosis and repair process of a Tektronix 465B, SN 37xxx, suffering from a display that was horizontally compressed and shifted far to the right. When operating, the display showed only 3 divisions trace width. In addition, the trace start could not be forced to go anywhere left of the centerline on the graticle. (THIS IS A CLUE!) All the typical sweep functions and vertical amplifier functionality appeared o.k. Just a horizontally shifted and compressed display. (THIS TOO IS A CLUE) The Beam Finder was not centering the beam either, but it was going center and just off the top of the screen. I noted this as a possible "other problem" as well as a symptom. This scope had been working perfectly. It is my backup scope. Fired it up after a 6 month inactivity in climate controlled storage. No particular reason for failure noted REPAIR PROCESS ONE) Since it had been stored, I did the usual "clean the switches/exercise the switches". Nothing changed TWO) Opened up the scope and started taking measurements. No board removal required. Just remove the case and face the scope screen to the right so it matches the orientation of the diagrams. I was pretty sure the PSU was right, thanks to relatively recent recap by my favorite scope tech, my brother Mike - but I checked PSU test points on A4 board anyway. Examine Figure 8-7 TP 4340, 4437, 4338, 4339 and 4439. All these voltages were exactly right. They are printed on the board there. I did not check CRT HV, since the beam was bright and sharp. THREE) Upon visual inspection of the A4 board, I found a couple of suspect looking tantalums which I shotgunned in there because I could - but to no avail. C4441 in particular looked bad. Screen still offset. Noted a couple of resistors on A4 that looked like they were running warm as well. R4368 and R4369, and noted them for future attention. Checked Axial Electrolytic C4461 by lifting one end. LCR meter said cap was o.k., so I put it back as is. FOUR) Checked the following trim-pots on A4 board. NOTE: IF YOU ADJUST THESE YOU WILL HAVE TO RECALIBRATE SOME - Move with discretion and note positions so you can at least get them back close. XGain control, R4381 - no effect on horizontal width, i.e. inoperative (THIS TOO WAS A CLUE!) X10 gain R4275 - working but off to the right as expected. X1 Gain R4274 - working, showed a very small adjustment range (as expected with a horizontally squashed display) Note that these Bourns trim pots are known to fail. If they fail, your display will go black. Ask me how I know. :-) But mine were fine this time. FIVE - FIRST PROGRESS) I finally got smart and ran a diagnostic test I got here on TekScopes I/O. The test is simple. Put the scope in X/Y mode and supplied the front-panel calibration oscillator to the x/y inputs. This is a good tip, posted on this forum somewhere, and repeated here. I quote below the exact language of the test routine. """""Put the scope in x-y mode (to bypass all the sweep generator circuits) and drive both x and y with the calibration source on the front panel (it's just a handy signal source). If you a.) still see width compression there, the problem is downstream of the sweep generator. If you b.) no longer see width compression, then the problem lies before the deflection amplifier."""""" I observed condition a.) Therefore, something wrong "downstream" of sweep generator itself, in the horizontal amplifier post sweep circuit. Now I finally knew where to start looking. I checked the +15 and -8 voltages at the front panel position indicator potentiometer and observed that they seemed reasonable when the pot was turned. That put me firmly on the A4 board itself. I re-read Section 465B manual section 3-19 and 3-20, and the description of the "Input Paraphase Amplifier" / "Gain Setting

Hello all I just picked up a 2246 scope that won't power up. Although I'm a very experienced tech, thought I would ask for any common SMPS faults before digging in further. The +44VDC on primary side is OK. Nothing on secondary side, except for short "blip" of voltages on outputs as it attempts to start up, then of course, drops to zero. The unit is absolutely spotless inside, doesn't look like its ever been used. (Cabinet exterior is also excellent) Thanks in advance, Mike

Hi all. Can't seem to find these anywhere. According to Sphere, these are, 'HARD to find 49xP Series Inverter Transistors! - 2N6587, TO-61, NPN, 10A/450V' - (SOLD OUT) Is these a feasible request, or shall the 492 be stripped and sold for spares? James

I recently purchased a Tek 561A oscilloscope and determined that there is something wrong with the timebase plug-in. I followed the troubleshooting guide in the manual and determined that there is something wrong with the horizontal amplifier and the normal sweep generator (according to the test points for these parts of the plug-in the voltages are way out of spec) any insight onto what the issue would be would be greatly appreciated

I just got a Tek 468 from one of the guys here in town. It's missing the back cover and feet. Does anyone have what I need to put my scope back together? Just the parts or an old junker would be great. I have a photo, but I don't know how to attach it here. Thanks! Mike Harmon, WB0LDJ mharmon at att dot net

Hi All, I am in the process of alignment after an extensive repair process of a very clean 2232. I have several questions, hopefully some answers:- 1. Does the rear right side, PSU section get quite hot, fan and air flow is not impeded and is working as intended, PSU voltage and ripple values work as documented, only -5.0 is sitting at -5.38 W9020? 2. Does anyone have a better understanding on the (13. adjust acquisition position offset (R7325 and R7335) when in test mode as documented on page 103 in section 5.10 of the SM? The Digital card must be in the service position to gain access to R7235 and R7335, this may present some alignment issues and position(s) of on screen lines, but happy to be corrected on this? Thank you in advance. Regards Gerald VK3GM

I recently acquired a Tektronix 2246 oscilloscope. It seemed to be working fine until I opened it and tried to check the test and self-calibration voltages (some of which out of the limits, but it is the same before and after the issue happened). Now no text is displayed, and the Readout intensity knob makes a dimmer version of the trace show up above it. If I try and open the Service Menu, etc. the screen just turns blank but I am able to quit out of it by pressing the right button. Photo in /g/TekScopes/album?id=300837 Any suggestions for how to fix this? This is my first time repairing an oscilloscope, so any pointers would be appreciated. Thanks for your time.

Hi All, I have been working on a 2782 unit with questionable freq. and amplitude correction data making the unit not usable at the moment. I have managed to get a working extension and serial IO card that gives me full keyboard service command control and feedback via trace mode, this allows me to look and store via screen dumps all correction data, good or bad. I am reluctant to take the next step using time consuming manual commands and measurement setup to try to align FM narrow/freq. and amplitude correction data. Does anyone have any prior knowledge or has worked on a 2782/4 in a past life? My next step is to work through the manual Cal process and document all steps and what I have achieved along with all data/sw. Now that I have a serial card and extender card working 100%, I may produce a bunch of extender cards with integrated serial interface to be made available if there is interest. Any feedback is welcome. Kind regards Gerald VK3GM

Hi All Anyone know what the correct voltage is at the input of L6 on the Power Supply. Its the supply circuit for the display CCFL. I'm getting -4.6v. My display is a dull shade of orange with no detail. A new display did not fix it. The output CCFL voltage is reading 768v pk-pk. Manual says is should be 1270v pk-pk. The other power supply voltages are correct.

The following photos have been uploaded to the SC503 - interesting waveform! ( /g/TekScopes/album?id=300884 ) photo album of the [email protected] group. * IMG_2525.jpeg ( /g/TekScopes/photofromactivity?id=3890274 ) *By:* Barry Breaux <groupsio@...>

Hi Everyone, I am in the process of reverse engineering 2 PCB:- 1, the 278x processor Serial IO PCB 2, an extension card 3, look at the s/w Bob has provided, can it be used under DOS. Lotus 123 and Lotus measure with 2 x GPIB control will be a challenge. Bob Koller was generous enough and provide me on loan several PCB to reverse engineer. I am starting another directory (2782 HW & SW service info) and this will contain all relevant data, schematics etc that I work through to resolve an issue with a 2782. I would also like to reach out to anyone who may have any additional schematics or any information on the 2782/2784. I have a unit with late revision PCB, some schematics do not appear to match. For example the A29 PCB 100MHz) ref source PCB in my unit it is a 670-9461-07. The bottom side of the PCB has an alternative schematic (no ECL). Regards Gerald VK3GM

Hi Guys, I am trying to fix some problems on my 11302, but I am stuck on a problem that seems very simple, but which I cannot overcome: a simple voltage divider. I am probably doing something wrong, but I cannot guess what (I added an album among the photos with the simplified schematic diagram). The 11302 "reads" the CRT cathode voltage using a voltage divider, selected by a 4051 analog multiplexer. It should be simple: the voltage divider is made up of a 20 M ohm and a 20 kohm resistor (the former is actually 2 x 10 Mohm resistors). So the output should be one volt for every 1000 volts in the input (well, 0.999). For me this is not the case: the divider output is significantly higher than it should be (with -1.6 V in the output, the input is actually -1.510 V). Easy, you say, one of the resistors has changed its value over time, but it is not so. I desoldered one extreme of them and they are all very precise. Another hypothesis was that the CRT mesh was causing some problem, but it is not: I disconnected it and nothing changed. I neglected the C1100 and C1420 capacitors because they could only lower the voltage, not make it greater. The last thing I didn't check yet is the dirt on the lower part of the board, but before disassembling it I wanted to hear your suggestions, if you like. I will be very grateful for any help, I am getting crazy. Thanks Gianni

Hi, it's me again... :) I was going to go on with the 11302 checking and tried to connect to TekCATS 2.19, but in the meantime I had updated the firmware to the 3.1 version and TekCATS refuses to connect to it. Has someone a more recent version of TekCATS or must I reinstall the old firmware?

Hi all Here /g/TekScopes/topic/107425848 H?kan kindly provided the service manual for this signal generator. I had time to have a look inside and found a shorted cap on the -15V supply (C1200 of A13 board), now the power supply seems to behave a bit better (the 3.6 V rail is still off, at 3.3~ ish Volts) According to the manual the oven temp normal light should come on but this never happens (this circuit doesn't seem to use the 3.6V rail so I ignored it for now) The manual says that TP1100 should be around 4.1-4.2 Volts for the "oven temp normal" light to come on but that never happens.. it hovers around 3.5 V and varies a bit. I noticed that R1156 gets really hot (>100 °C) but I don't know if this is a fault or not. I took the oven apart to check the thermal fuse but it seems ok... so I'm not really sure where to go from here. I updated the album: /g/TekScopes/album?id=296482 Can I plug the oven in without enclosure for testing? Disclaimer: I obviously have no idea what I'm doing... there doesn't appear to be any notable occurences of this SG on the net so I will try to find faulty or out of spec parts and hope any of you have a good idea where to start Thanks Luca

Hi all, So last year my venerable old 2465A developed a weird intermittent fault. After some time - arbitrary and not temperature related - this fault would arise whereby the screen would become *really* bright with some spurious artifacts showing up as well. When this happens, the screen brightness control fails to have any effect and I cannot turn that dazzling brightness down. Now, from what I've read, I need to monitor TP73's voltage ('grid no. 1' to the CRT) and see if it changes when the fault arises. So I've stripped the casing away and removed the HV safety/warning shield from the HV supply board A9 and attached a scope probe to TP73. The service manual provides a diagram of how the waveform on TP73 should look so I'm all revved-up waiting for the fault to materialize (which it invariably does when I try to use it to check anything). Guess what? I've had the damn thing on now for 5 hours and it's not missed a beat! Behaving perfectly normally with no sign of any screen issue at all. Bloody intermediate faults. I hate 'em!! Jinxie