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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

Hi. I have a HP54502A in fairly good condition I want to fix for my workbench. It fails on A/D test (pass D/A and rest) on CHANNEL 2 only. I have no schematics, just the SM, and if anyone knows of link to any it would be appreciated. Anyway, have anyone else successfully fixed this error before and what was it? I did see a blog online with at short in PS but ALL voltages seems OK and 5.2 adjusted according to SM. I have swapped the 2 ICs with heatsink around just to eliminate that. In lack of a schematics does anyone knows which IC is the DAC (A/D converter) so I at least can have a look around it and compare channels (CH 1 works perfect). Any hints are welcomed......... PS. the Dallas chips has been replaced before I got the scope with a DS1230Y so guess that is not the reason? I got the schematics for a 54601a is that too far off or similar in chip sets used? Cheers

Hello, I have a Tek P6248 differential probe, on which the micro wires in the head have unfortunately broken off. Unfortunately, the pinout of the wires, or the "Cinch" plug, is no longer recognizable and I haven't found anything online, even though this seems to be one of the most common problems with the probe. https://1drv.ms/f/c/a3cea52fd4e3ee5e/Ql7u49Qvpc4ggKM_AwAAAAACGN3PbgU5dBZXAw Perhaps someone here can help me. Best regards, Eric

Hi everyone, Yesterday, while working with my Tektronix 2465, I suddenly heard a strange noise from inside, followed by a very unpleasant smell. There was no smoke, and the trace was still visible on the screen. I immediately turned it off and haven’t tried powering it on since. I suspect it might be a Rifa capacitor gone bad, but I need to inspect the boards to be sure. After removing the cover, I realized that I can’t clearly see how to remove the A2 (Horizontal) and A3 (Vertical) boards. My main question is: Can I remove the A2 and A3 boards without taking out the A1 (Main Interface) board first? Or is there another trick to access them more easily? Any tips or advice from those familiar with the 2465 would be greatly appreciated! Thanks in advance!

Looking into a 465 S/N B260137 and trying to determine what seems to be causing the additional trace in background of triggered wave forms. Power supplies all look good for voltage and ripple. Suspecting trigger board but exactly unsure. Any thoughts would be welcome Added photos to album : 465 Scope with Ghost trace Craig

Hello I am at a standstill with figuring out why the CRT of my 2465A is blurry and won't focus. I purchased this unit from Government Planet last summer with the idea that I would probably have to troubleshoot it. I turned it on and it made a screeching sound and had no display. I thought the sound was coming from the fan but no it was the high voltage board. Checked the voltages on J119 and they were all good with the exception of the -15V rail which had high ripple. Decided to recap the LVPS with a kit from Condor Audio. This fixed the -15V rail. Turned it on and there was a blurry dispay but intermittent screeching from the high voltage board. Looked closer at this and discovered that the ceramic of T1970 was cracked in several places. Purchased a new high voltage board from QService and installed it. Now no screeching but the display remains blurry with the Read Out letters wider and taller than they should be and the same for the traces. I have uploaded 2 pictures to the file Amberwave 2465a that shows what I'm talking about. I checked voltages to the CRT socket at pins 8(31V), 12(-108V to -186V) and 13(-192V to -224V) and they look reasonable. DAC reference is right at 10V. When I input a signal into the scope I can just make out that it is a sign wave. I just don't know where to go from here. I have invested a lot of time and dollars in this scope to just give up. It would seem that this isn't a HV board issue as both boards gave a blurry image. Could this be the CRT tube itself or one of the IC's? I would really appreciate some guidance on where to go from here from someone more experienced with these scopes than me Rusty Hilliard W0RGH

Hello people of TekScopes, I have a Tektronix 7B92A that needs repairing. It has a very severe horizontal deflection off to the right of the display, but the sweep is also jittery and not stable. I've probed the sweep generators and I've confirmed they are not the problem as the sweep waveforms are beautiful. I'm pretty sure the problem is in schematic No. 6, the output amplifier for the plug-in. The only problem is, this part of the circuit is on a section of the A6 main board that is under the A7 logic board. Because of this I can't reach any of the points I need to test. I've tried removing the logic board and probe the A6 board that way, but that stops the plug-in from sweeping, which is useless for testing points on the output amplifier. I could just solder a tiny wire to every point I need to check and do it that way, but some of the points I need are on socketec transistors and I don't want to risk solder filling up a socket. Any tips? Benjamin

Just a quick one which might help anyone whose scope boots fine but then has no display.. Obviously there are several reasons this might happen, however whilst working on one of these last week, this problem was created by a faulty U950, Z-Axis Hybrid chip. 155-0242-00. Swapped the chip and the display came back perfectly. James

Gianni Becattini <Giovanni.becattini@...> added the photo album Bewitched voltage divider (11302) ( /g/TekScopes/album?id=300803 ) : see my emailò

--I have designed a Male to Female Extender Card designed to install between a flexible Extender cable (067-0645-02) and the Plug-in being tested. It uses a 4-pin, 0.1" pitch header on each line jumpered between pins 2 and 3 to connect through, but removable to measure current. etc. With the jumper installed pins 1 and 4 are available as test points on the line. The board is 2.5" long not including Female connector, and 4.5 inches wide to accommodate the 28-position Female connector and PCB edge fingers It will have 4 slots between the fingers in the standard keying locations for the TM500 series modules. The cost to make the board properly with hard gold over nickel fingers is more than I want to spend for the 2 boards I need ($300). If anyone else is interested in a well made pcb like this let me know. I used Sullin for my Female connector -- they are excellent. Steve

Fellow techies, I got this Email tonight. The sender is in Oregon, which means I'm not in the best position to help. Could someone a little closer to the 503 area code step up? It sounds like a good opportunity to try and make sure an estate full of test gear gets properly redistributed instead of trashed. The sender's return Email is nogreenpeppers@... Thanks! -------- Forwarded Message -------- Hi, I have no idea if you can help me or not so here goes... My name is Kristin and I am the executor of my uncle's estate. He has a significant amount of specialized electrics equipment (oscilloscopes, multimeters, and other stuff that I am not sure what it even is). I have someone that has offered to purchase the entire lot of it. However, I'm looking for someone that I can look at the stuff and give me an idea of what a good price might be. As the executor, I can pay for your time to do an assessment, if this is something that you can do. If you are interested, or know someone who might be, please let me know. By the way, I found your email by looking up the TEK Country Store. He used to go there a lot and I assume that people who are familiar with the place might know what some of this stuff is. Thanks for any help you can provide. Best, Kristin (503-840-4458)

I had one cracked knob on a 2465, so I pulled another to be able to use that pot, and the pulled one lost most of its spring clip that keeps it on the shaft of the pot. What methods are known to work well for using knobs like in my photo that have lost some of their spring clip parts? Does epoxy putty help a knob stay on? Does epoxy putty work too well and never come off? https://www.ecosensory.com/tek/tek-2465-2446-2336-knobs.jpg

Does anyone know what is going on with ko4bb,com? If you click on manuals than any link it just takes you back to the main page. Sam W3OHM

A photograph that was used for the cover of EDN magazine was posted to the Tek wiki site today. The photograph was published in November 1982 to support the introduction of the 7D20 and to reinforce the modularity of 7000 series. I apologize for the color balance. The photograph was badly faded to orange. I made a color correction but with my yellow cataract vision, I over emphasized the blue. Thank you Kurt R. for posting the photograph. https://w140.com/tekwiki/images/thumb/5/5b/EDN_ModularInst_7D20.jpg/1505px-EDN_ModularInst_7D20.jpg