I've read through a lot of posts regarding the replacement fans. Is there anything outside of the parts description from the service manual that I need to take into account? Both my 'scopes need the fans replaced. Tried cleaning and re-oil; no difference. Looking for something that is quite yet moves the volume. Is there a good solid replacement? Thanks, Monte

I am new to the forum and my trusted Tek 2465A just failed me. On startup it gives an error code that says Test 05 Fail 24. I can clear the code but then the scope fails to trigger and when I change voltage scales on any and all of the channels the horizontal line will jump way off screen. I can bring it back to the center by adjusting the vertical but if I change scales it is off the screen again or nearly so. Any hope for my scope? Where should I begin? Thanks in advance for reading... and helping me figure it out I hope. John w. N7ZMG

FOUND some 60GHz and under mixers. A couple still worked and fixed a couple. I gave up with the 100GHz and over mixers. All from ebay. One fraud attempt off ebay thwarted. I am learning FreeCAD and am designing one (90-140G) "referencing" the Tek designs. I have the diodes already. Any higher frequencies are doubtful. I won't have a RF source and the size and precision needed may get to be difficult to CNC for a reasonable cost.

Hello everyone, I would like to tell you about the error. The oscilloscope can be switched on, the fan is running and the Key lighting stays on permanently. On the A11 DRAM Processor/Display Board number 8 lights up on the segment display. The device had a problem with all SMD capacitors. Then I replaced all the capacitors and cleaned all Circuit boards. Unfortunately, this action did not fix the error. I then started troubleshooting using the service instructions. Here are the links to it: Volume 1: https://w140.com/tekwiki/images/6/62/070-8312-01.pdf Volume 2: https://w140.com/tekwiki/images/4/48/070-8313-00.pdf I carried out the diagnosis on Volume 1, page 187. The fan is running and after 30 seconds the key lights doesnt turn off. Thereupon According to the instructions, I troubleshooted the processor/front panel procedure (Volume 1 page 195). I checked all the required voltages on connector J2. all OK. The clock signal (3.125Mhz) is also present. According to the instructions, the communication link between the A11 Display/processor board and the A12 front module is faulty. The A12 Front module is most likely defective and should be replaced. There are a lot of troubleshooting instructions described in volume 2 but I think Unfortunately not one applies to me. I think there are missing a few pages. I have measured the processor on the A12 board (Volume 2 page 218). Unfortunately the 3rd page is missing there. I noticed that there was no 2Khz signal on pin 2 of the processor (U1). This means there is no 1Khz square wave signal to set probe. The operating voltages are OK. The clock signal from the A11 board is also present. Does anyone have an idea what this could be? Does anyone know how I should proceed? I wish everyone a merry Christmas! Greetings from Germany Paul

Hi all, New to this forum (unbelievable, right?), and I’d like to thank everyone for the great info shared here already. I’m a proud new owner of a Tektronix TDS8000 scope, which I purchased as “broken” on eBay (the issue was with the display, which I’ve already fixed). While waiting for the replacement part to arrive, I’ve read through a lot of threads and noticed that many problems with these devices seem to arise due to the loss of NVRAM and CMOS contents caused by dead batteries and even the loss of CPLD contents. I count myself very lucky, as my unit doesn’t show any errors and passes compensation, etc. I want to ensure that I back up as much as I can from this device before I risk losing anything critical, like calibration constants. Here’s my plan: - Dump the hard drive contents and create a raw copy. - Dump the BIOS to preserve its current state. - Dump the CPLD contents with a Xilinx JTAG programmer I have laying around. What I’m less certain about is the proper way to back up the NVRAM contents. Could anyone advise on the best approach? - Is the NVRAM and its battery seated in a socket, so I can remove the combo from the board and read it our externally? (I have hardware for reading chips directly.) - If not, is it possible to perform an in-circuit dump of the NVRAM with the same chip-reading hardware? - I’ve noticed the VxBoot bootloader offers memory-dumping options. Would this provide a way to access and back up the NVRAM? - For the 5000 series scopes, there’s a tool called Savecal5k (https://www.eevblog.com/forum/testgear/savecal5k-calibration-backup-disk-for-tektronix-tds5000-oscilloscopes/). Does anything similar exist for the 8000 series? Any advice would be greatly appreciated. I’m more than willing to share my findings and dumps to help others maintain their scopes as well. Thanks in advance!

I could not find any description of the Tektronix Tristar DSP. I understand that the DSA series probably was not very popular, but as far I know it was widely used also on the TDSs. Any suggestion for where to search? Thanks

When I wanted the 11300 version of TekCATS, I used to find that for the DSAs. Now I wish the DSA version but I cannot find it anymore... :) Can someone help me finding it? Thanks

The following photos have been uploaded to the Pictures of substitute parts for the 12au6s in my 575 curve tracer ( https://groups.io/g/TekScopes/album?id=299641 ) photo album of the TekScopes@groups.io group. * IMG_1332.jpeg ( https://groups.io/g/TekScopes/photofromactivity?id=3869413 ) * IMG_1331.jpeg ( https://groups.io/g/TekScopes/photofromactivity?id=3869414 ) * IMG_1330.jpeg ( https://groups.io/g/TekScopes/photofromactivity?id=3869415 ) * IMG_1334.jpeg ( https://groups.io/g/TekScopes/photofromactivity?id=3869416 ) *By:* Anita Abranovic <anita.abranovic@...>

Anita Abranovic <anita.abranovic@...> added the photo album Pictures of substitute parts for the 12au6s in my 575 curve tracer ( https://groups.io/g/TekScopes/album?id=299640 ) : Can anyone

Anita Abranovic <anita.abranovic@...> added the photo album Pics of substitute parts for the 12au6s in my 575 curve tracer ( https://groups.io/g/TekScopes/album?id=299639 )

Hello from central TX! I have a DC503 counter where it's difficult to get the input A level adjusted correctly. Connecting a scope at any point between the input JFET pair and the TTL logic, you can see that a minuscule adjustment of the level knob causes the signal to swing from one extreme to the other. If it's just been turned on, with effort I can get it adjusted so that it will work. As it warms up it will need additional adjustment, and it becomes more difficult to find the sweet spot. Q35 and Q40 are JFETs at input A, both 151-1022-00 (selected 2N4392). Q35 gets the input signal, while Q40 is connected to the input level pot. Q40 gets extremely hot in operation, so much so that I'm surprised I don't have a circle burned into my fingerprint where I touched it. I thought this fet may be damaged due to a voltage excursion on the rail [1], but my (very cheap) component tester shows similar parameters for Q35 and Q40. Transposing the two transistors gives the same results: the one at Q40 becomes extremely hot, the signal coming out looks the same, and it's difficult to adjust the level. Does it seem reasonable to assume the two transistors are supposed to be around the same temperature? If I feed a 1kHz square wave into inputs A and B and check the signal between the JFETs, on input B I get a nice square wave while on input A I get a flat line, with spikes alternating up and down where each edge should be. Input B uses a different JFET but the circuitry before the JFETs is identical to A, so I'd expect the waveform to be similar. If anything, input A should be better since it's good to 100MHz while B is only good to 10MHz. The component tester also indicates Q50 (the next transistor in circuit) is ok. Probing the pads with power off and the transistors (Q35, Q40, Q50) removed, my ohm meter shows values that seem reasonable for the connected circuitry. There's drift, but it doesn't seem sufficient for the level of heating. For example, R35 (to +5) is spec'd at 100 ohms and measures 108, while R40 (to -22V) is spec'd at 510 and measures 508. Resistance in the level pot seems ok and changes smoothly as the knob is turned. Power rails are in spec. What would you recommend doing next? Look elsewhere because it's normal for the transistor to get so hot? Desolder adjacent components to measure them individually? Find a replacement jfet? Or something else? [1] Q40 is connected to the -22v rail through a 510 ohm resistor. The rail's regulation failed due to a bad pass transistor in my TM503, putting the rail at 30-something volts below ground. Regards Mark

I have recently obtained a 494/AP unit and copies of the service manuals. However, the Log Amp board shown in my service manual vol 2 is not the same as the one fitted to my unit. Can anyone please help identify the board version and advise where I can find the correct layout/parts list/circuit diagram for this board? It is mainly surface mount stuff and has the identification number of 670-9091-03. This issue has been raised by John Miles in his very useful service notes for 49x etc series of analyzers but no advice was given on where to find the technical information for this board. Any help with this issue will be greatly appreciated. Thanks in advance for any help, Richard, Thailand

hey folks , I have a 922 that is not working on one channel . Before I go real deep in it I thought I would spend some time cleaning switch contacts as I've read that sometimes solves this issue . What is a good contact cleaner to use ? Any other pointers ? thanks animal

I showed years ago that a 7CT1N could be used in a DSA602A in X/Y mode. There is an album 7CT1N-DSA602 in the photos folder. There are not many 7000 modules that would be useful in a 11K mainframe if you have access to all true 11K modules. The 7CT1N and 7A22 look like the best candidates for me. Christian.

I've a Tek 2465B that I recently acquired, it was described as 'no trace' and that is true, when powered up various leds flash for a bit but no trace is visible, with or without the beam finder pressed. It's a 1996 model but no surface mount caps. The first thing was to check the power supplies via the main board test point (actually a 14 pin DIL socket) J119. Measuring the voltages I get: Pin Measured Spec 1 -14.95 -15.0 2 3.940 5.0 (digital +5v) 3 -18.66 (-15v unreg) 4 10.00 10.0 5 -4.986 -5.0 6 15.01 15.0 7 0.0 0.0 (gnd) 8 87.0 87.0 9 42.47 42.4 10 0.008 (unused) 11 -8.03 -8.0 12 0.761 5.0 (analog +5v) 13 -1.365 (?) 14 -1.363 (?) So from this it looks like the +5v for digital is low, and the analog +5v is very low. Looking at the PSU boards there is no evidence of either bad/leaky caps or overheated components. Whats the next thing to test?

Thank you John for sharing the Youtube URL to the original US color version of the Turbo Encabulator https://www.youtube.com/watch?v=Ac7G7xOG2Ag&ab_channel=ParadigmProfits This version was done sometime in 1977 performed by Bud Haggart. Additional information may be found on the wiki pages. The original concept was apparently from England on the 40's, and in 1962 GE created a published specification sheet. https://groups.io/g/TekScopes/album?id=299609

Hello people of Tekscopes, I am curious to know what the function of the four holed (socket?) is on the top of each 7000 series plug-in "mater". I've 3D modeled these maters but never the 4 holed bit as I can't see a function for them. The main frames do have a matching 4 holes too. Were these holes for somekind of socket for extra functions that Tek eventually scrapped? Thanks, Benjamin

Hello. Winter is on the horizon and so I have started to work on Tektronix projects. While doing that I came to the realization that I have thousands of parts from scopes that I have stripped for various reasons. It also made me realize that I would never use probably any of this. Eighty years old now. To find a home for this parts horde I have no interest in eBay. What I could do is open it up to requests to see if I have something you need or could use. I do not want to sell any of it, but I would be willing to send it out for a small fee and the postage. If this is of interest you can message me and I will contact you by direct email. I will let you know if I have what you want, and if I do what the postage would be. I am willing to give this a try if you folks are. I would accept any form of payment including PayPal. Sadly we have no postal service here in Canada right now, so any shipments would have to wait until it is settled. Typical costs here would be: Anything that can be sent by letter mail about $8 US. Small packages $13 to $20 US Larger items cost could be found on Canada Post, UPS, FedEx etc.

I've been looking at this recently converted 7613 to check it out and hopefully improve the focus and other screen adjustments. Going through schematics I was reminded of something I saw that bothered me earlier while redoing the wiring and also adding the little fan, so I checked it out. It appears that the three-wide mainframes with linear supplies have no local fault bypassing of the remote sense lines. Nothing for that, and no apparent OVP functions either. In all the 7Ks I know of, the low voltage regulators have remote sensing (even for the ground), all carried back from the main interface board where everything converges. The four-wides with SMPS all have safety local bypassing resistors on the LV regulator board, so that if any feedback connection is lost, they remain in control near the proper setpoints. They also have somewhat intrinsic OVP since the pre-regulated voltages have only a few volts of overhead going into the regulator circuits, some supplies are sort of monitored for improper voltage in some models, and the primary side has some OVP too, so they won't get too far out of whack. In contrast, the three-wide linear supplies have nothing to protect against going open-loop if either the sense line or the supply feed connectors are unplugged for instance. At either end too - losing a connection at the LV regulator or the main interface could be very bad. You get a choice to OV just the supply or the whole thing. On top of that, the overhead voltage for the regulators is huge as required to handle wide line voltage and load conditions. During the fan experiments, finding that the raw supply to the 7613's 5V regulator was nearly 12V really brought it home to me. The other supplies likewise probably have quite a bit of overhead too, roughly in proportion, and again, there's no OVP except for whatever breaks down and burns out first. I vaguely recall measuring them at some point to make sure the transformer/rectifier unit was OK, but it was with no load, so it's not quite as bad with the real loading as these numbers would indicate. I think it was about 27V for the 15V regulators, and 74V for the 50V ones, no load. Imagine what could happen if these went open-loop from accidentally or on purpose unplugging one of those connectors. I have done that many times on the four-wides with no problem, because I know they can handle it. I'm surprised and disappointed the threes can't, and glad that I didn't accidentally do that while doing all this work on the 7633 last year and this 7613 just recently. In fact, I'm vaguely now recollecting that years ago when I first got that 7403N I started poking around in it live as I sometimes do for my 7K troubleshooting, and something popped. When I started looking to use the carcass recently for the 7613 project, I found that LV regulator board is shot, and so is another I have from something else long ago. I have looked at the 7613, 7633, and 7603 manuals, and all use the same LV board (I have all 670-1376-XX) but possibly some different dash numbers, and they all look the same. My two shot ones are -06. Since I'm still kind of working on the 7613, I'll probably add safety resistors on the LV board, and will eventually or never do the 7633 and two 7603s - that's all of these kind I have. At least it's good to be aware of it and be careful. I'm right now looking at the board layout picture and marking the nodes to figure out good spots to add the resistors. I am getting tired of this thing though - about a couple dozen put-and-takes so far for that LV board. Ed

Seen at these links: https://pearl-hifi.com/Groups_io/Tek/Bezel_Graticule.jpg https://pearl-hifi.com/Groups_io/Tek/Bezel_Graticle_and_Camera_Mask.jpg are a Tek 500-series CRT bezel, an 8cm x 8cm graticule and what I assume to be a bezel for use with a scope camera. The graticule is in excellent shape but needs the red tinted edge light holes repainted. $US30.00 + Canada post shipping buys the lot, PayPal is good Hit me off-list at sales@... Best regards, Bill Perkins PEARL, Inc. No. 80 — 5th Ave SW, Nakusp, BC, V0G 1R0 + 587 578 4434 Cell' and SMS + 250 265 2552 Landline https://www.pearl-hifi.com