hybridfree/eevblog-posts huggingface dataset:
Tektronix 7854 horizontal adjustment - Page 1
Forum section: electronics / repair

author: little nellie
author_rank: Newbie
timestamp: November 23, 2019, 03:46:13 am
content: Hi, is there a way to adjust the horizontal position in the 'store' mode? I am able to adjust the horizontal position in the 'scope' mode with the timebase. But when switched to 'store' the display is shifted left about 1/8", unable to locate any knobs for adjustment in that mode. thanks

author: David Hess
author_rank: Super Contributor
timestamp: November 23, 2019, 02:44:02 pm
content: The service manual includes all of the details for the rather involved display calibration procedure. There are trimmer potentiometers to adjust position and scaling of both the analog and storage display elements so that they align with the graticule and align with each other.
Tektronix 7A19 Repair - Unobtainium 155-0068-00 suspected - Page 1
Forum section: electronics / repair

author: FlexibleMammoth
author_rank: Regular Contributor
timestamp: July 20, 2022, 01:26:41 pm
content: Hi,i have finally come around to revive a very old and very dirty Tek 7904 500MHz mainframe oscilloscope that I was gifted by my old physics teacher about 10 years ago. I am now debugging the 7A19 vertical amplifier, which shows no signal no matter the settings.What works:- All readouts (V/div, IDENTIFY, invert)- Invert trace switch- Coupling switch- Fuse and attenuatorsWhat doesnt:- There is essentially no output signal. A 100mVpp signal yields about 7mVpp on each of the differential outputs (image 1).- Position has no effectI have traced the signal through the amplifier; it is a nice 100mVpp from the input, through the fuse, through the attenuator, through the fixed delay line and right up to the signal amplifier U100 and trigger amp U40, which are unobtainium Tek parts:https://w140.com/tekwiki/wiki/155-0068-00As a bonus, they are mounted right below one of the rotary switches, so I can't really measure at the pins. However, both devices get warm (but not excessively, just enough to "feel appropriate"). No other obvious hotspots using a thermal imager.After the chips, the signal is strongly attenuated (image 1: Channel 3 is the 7A19 output; C1 and C2 are the vertical amplifier output), both before the polarity switch at R39, R49, R99, R109 as well as after the polarity switch right on the trace. Service manual is here:https://w140.com/smb/7a19_sm.pdfFor reference, I have included the same measurement from a working 7A12 vertical amp (image 2: Channel 3 is the 7A12 output; C1 and C2 are the vertical amplifier output).Any ideas? If both those devices are shot, I don't really see a way to fix this, since ebay has only one of them, and that one is 30€. Also, I am not sure how that would have happened - there is an input fuse that should catch the roughest abuse. ESD maybe?Thanks,Andreas

author: perdrix
author_rank: Frequent Contributor
timestamp: July 20, 2022, 03:18:02 pm
content: The best place for advice on these puppies is the Tekscopes mailing list at groups.io.David
tektronix 7ct1N and 7603 expert needed - Page 1
Forum section: electronics / repair

author: Rollin Hand
author_rank: Regular Contributor
timestamp: May 29, 2020, 01:37:03 pm
content: Hello I got this set up but the curves on the crt display are upside down and reversed .What I m doing wrong?I connect the horiz-vertical out to an 7b70 on amplifier mode on the horiz in.Also I connect this cable to channel 1 of the 7a18 amplifier with no results at all.Also on the dc output of the 7ct1N never reaches the 300 v out like 160 c and the caution lamp goes on at approximate 40 volts,I replace the 2 resistor of 240 ohms and the 2 50uf capacitors there where at 25 v,very originals.The 2 180ohms 1watt resistor on the 30v supply are out of value like 220ohms and 300 ohms each but I dont think these are relevant at the moment.Also with this modules there is no screen read out on the CRT is this normal?Thanks for the help

author: David Hess
author_rank: Super Contributor
timestamp: May 29, 2020, 03:00:11 pm
content: The 7CT1N does not support the readout which is what the "N" means.My guess is that the horizontal/vertical switch at the top of the plug-in is not working properly.
Tektronix A6302 current probe hall effect sensor diagnosis - Page 1
Forum section: electronics / repair

author: chrisLF
author_rank: Newbie
timestamp: September 20, 2019, 05:06:44 pm
content: Hello everyone.After lots of browsing and eevblog videos this is my first post - please be gentle :-)I've been amazed by how many experienced and clever people there are on here, so a big thank you to everyone who's posted all the comments I've been reading for the last while.So here goes...I'm trying to diagnose a Tektronix A6302 current probe.I bought it off eBay as a non-working / untested but complete system comprising the following.TM502A frame : All voltages and the transistors look fine so hopefully can rule this outAM503 : had a blown fuse and I traced the cause to a shorted bridge rectifier - all supply voltages now as per manualA6302 probe : well worn but no visual mechanical damageI also have another working set, so have swapped out the parts and the fault always follows the probe.The overload LED comes on whenever the probe is connectedIt disappears during a de-gauss but comes back afterwardsLooking when I first opened the probe, I found a missing wire and also that one of the common mode inductor wires was unsoldered / broken off - I replaced itWith the inductor disconnected so there is no AC sensor, I can see the Hall effect react to DC via the amplifier and a 50R scope input. It only works up to about 200mA without setting off the overload LED though, and looked pretty linear over that range.With the inductor connected, the LED lights permanently.I took some DC resistance measurements across the disconnected sensor headthe coil measures 1R27Hall sense to hall supply between 100 and 110RHall(-ve) to hall (-ve) = 20R (Datasheet shows 10+10R so that looks goodI also took some voltage readings at all the probe connections within the AM503 and are in the table belowI started with no probe connected, then my good probe, then the bad probe with no inductor connection, then with the inductor, then with the top of the core mounted, and finally fully re-assembled and locked jaws.I calculated the differential voltage across the two hall outputs in one of the lines below.I can see that the output amplifier seems to hit either rail whereas with the good probe its around 0VAlso noted the good probe has both hall outputs around 600mV - is this related to the bias resistor?When the probe is un-assembled but with the top of the core in place, I can feel the magnetic pull when powered.During turn on and de-gauss, I can hear the probe head vibrate so that looks good.It's quite a complex system to get my head around with a full feed back system, so hoping for a few pointers from someone with experience in this system.I'm obviously hoping the head is not damaged, and I've read that Overload LED = fried hall, but as they are expensive to replace I want to be sure either way.Thanks in advance

author: chrisLF
author_rank: Newbie
timestamp: September 20, 2019, 05:23:10 pm
content: Here's a few pics.In the posts I've read, I've always found the pictures really handy to help understand what's going on.
Tektronix ADA400A CMRR fails miserably - Page 1
Forum section: electronics / repair

author: FlexibleMammoth
author_rank: Regular Contributor
timestamp: September 22, 2021, 10:33:07 pm
content: Dear all,I have recently treated myself to a Tektronix ADA400A differential probe. It is basically a TekProbe version of some older series 5000/7000 plugins.I have started doing a performance verification, and found that while gain, zero offset and LF CMRR are excellent, the HF CMRR is way off. Like, "10x higher than it should be" off.The manual  has a procedure for alignment, so I went through that. On page 47, HF CMRR is adjusted to be <1mV when applying a 100kHz, 1Vpp, 50Ohm terminated signal to both inputs. For my probe, it's more like 12-13mV (see attached screenshot) and I am unable to get it down further using CV4 and R18.Sanity checks: I have verified +/- 15V and +5V on the board. It appears the last wire (Brown) does not carry -5V, but rather indicates the attenuation factor to the scope. For giggles, I have played around with different lead lengths on the inputs, but even a 2.5m length difference does not really change the picture other than introducing additional spikes from reflections. There is no visual damage to any component that I could see and no leakage from the capacitors.EDIT: I am using the Siglent SAG1021I frequency generator for my experiments. While it does not have great rise times, it's the best I have on hand and it should not really matter at the frequencies we are interested in here, especially when the same signal is fed into both inputs.What am I missing here?https://download.tek.com/manual/070916402.pdf

author: alm
author_rank: Super Contributor
timestamp: September 22, 2021, 10:53:36 pm
content: Are you feeding it a sine wave as the manual specifies? The screen shot looks like the higher frequency component of a square wave to me, which would be much higher frequency than the fundamental frequency. So you might actually be measuring the CMRR at 1 MHz instead of 100 kHz.Tektronix does specify a length-matched cable:https://w140.com/tekwiki/wiki/067-0525-02.

author: FlexibleMammoth
author_rank: Regular Contributor
timestamp: September 22, 2021, 11:10:02 pm
content: Oh. My. God. Thanks for noticing! I was feeding a square wave, which was still configured from the last measurement. That one naturally has frequency components to the moon. I will retry and report back asap.Also, thanks for the hint about the special Tek cable - unfortunately eBay was not kind on that one, so I had to come up with *ahem* custom solutions which definitely is not just the shortest wire I could fit between the inputs.EDIT: As expected, this magically cured the CMRR illness and i was even able to adjust to <100uV common mode voltage! I am leaving this post up for the next person that is scratching their head and as a humorous reminder to RTFM carefully. Thanks again to alm for your quick help!
Tektronix AFG3021 - Page 1
Forum section: electronics / repair

author: hitecelec
author_rank: Regular Contributor
timestamp: July 23, 2019, 10:49:14 am
content: Hello Allwhat is the fuse rated voltage and type of fuse ie very fast acting/fast/slow of the 0.125Amps fusesupplied with the fuse adapter 013-0345-00. the tek part of fuse is 159-0454-00. this adapter and fuse are supplied with tek AFG3021thanks in advanceRegardsAnand

author: shuvodutta
author_rank: Contributor
timestamp: July 23, 2019, 11:47:23 am
content: Hi,Specification for this Tek. Part No. (P.C.B. Mounted, Through-Hole with Axial Lead, Miniature Fuse) is nowhere to be found. This is the closest I could get,https://www.littelfuse.com/products/fuses/axial-radial-thru-hole-fuses/pico-fuses/251/251_125.aspxIt looks they should be Fast-Acting/Very-Fast-Acting & better to be used with Lower Voltage Rating (as they're supposed to Protect Output Stage of Tek AFG3021. 125V AC/DC @ .125A is the Voltage Rating for the Littlefuse 251 Series (PICO Fuse) I've linked above.).

author: hitecelec
author_rank: Regular Contributor
timestamp: July 23, 2019, 11:55:45 am
content: Hello DuttaThanks for the assistanceRegardsAnand
Tektronix AN-USM-488/2235 High +8.6 V Ripple - Page 1
Forum section: electronics / repair

author: jdragoset
author_rank: Frequent Contributor
timestamp: July 10, 2019, 01:40:14 am
content: I get roughly 50 mv p-p, seems like it should be less than 5.Checked a few W jumpers with a milli-ohm meter and W-960 (main +8.6 V from PS) measured 1.2 milli-ohms.Gives an mV drop indicating a current of 0.4 amps.Seems like all of the wire jumpers = 1 to 1.5 milli-ohms (depending on length), meaning they can serve as shunts for measuring millivolt drop and calculating current (current in amps = millivolt drop/milli-ohm shunt.I don't know if the Tek folks intended this, but it does give a good rough estimate without de-soldering.Back to the problem,I'm suspicious some or all of the electrolytic caps have gone open circuit and not much filtering going on.Given the 0.4 amp total current, I'm not really suspecting shorted caps or other components.Scope behavior is normal other than high 40 KHz on 2/5 mv/div either channel.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 10, 2019, 06:30:05 am
content: Add a capacitor around 100uf 220uf 470uf at 16v on the 8.6vdc line and see what results it gives ?? maybe add an 0.1uf in parallel too ...

author: floobydust
author_rank: Super Contributor
timestamp: July 10, 2019, 05:51:22 pm
content: Just replace all the electrolytic capacitors in the power supply section. It's less time and money than troubleshooting each one.The blue Sangamo (in 2235) caps have epoxy seals that crack with age and they dry out. The Sprague 672D is also very old, time to change them.For the 2235ATek upsized all the +/-8.6V, +5.2V rail capacitors from 840uF to 1,000uF. Total six. I use UCC EKYB250ELL102MJ20S, Digikey 565-3892-ND, 1,000uF 25V to fit and has lower ESR, under $1 ea.edit: fixed typo in 2235,2235A PSU capacitor list spreadsheet, nowVer2Ver3

author: jdragoset
author_rank: Frequent Contributor
timestamp: July 10, 2019, 08:31:34 pm
content: I have twelve 1000 uf I will change all six tomorrow.Also have some 2.2 and 22's on the way for several other loationsThanks,

author: jdragoset
author_rank: Frequent Contributor
timestamp: July 16, 2019, 03:10:33 pm
content: Bingo!Changed +,- 8.6 V, + 5.2 V, + 30 V & + 100 V PS caps and problem is solved.Checking what was removed with the LCR meter, it's easy to see that the rest of the electrolytic caps also should be replaced.Thanks,
Tektronix analog scope issues - Page 1
Forum section: electronics / repair

author: 1audio
author_rank: Frequent Contributor
timestamp: March 06, 2022, 07:28:08 am
content: I have two vintage tek plug in scopes with similar issues.First is a 5112 dual beam where 1 beam's vertical deflection amp is intermittent. One of the plate drivers stops amplifying and the deflection stop at the mid point.The other is a 7403N where the horizontal deflection shrinks and then becomes a line.I have looked at both carefully and touched up solder joints, looked for cracked traces etc. There is a mechanical aspect (tapping can get it working). The signal seems to be at the input when its not working. When probing sometimes the circuit starts working. The 5112 circuit is quite simple. The 7403 a little more complicated. On the 5112 the failing amp acts like the connection from the emitter of Q104 to the collector of Q106 is intermittent but it checks OK with fresh solder joints. On the 5000 series the transistors are soldered in and a PITA to get out with the board mounted. Is there any history of intermittent connections inside transistors?The 7403 has a similar problem in its horizontal amp. However everything checks OK when on the bench until it sits for a while.I'm looking for any suggestions, ideas or ideally experiences fixing these problems.

author: m k
author_rank: Super Contributor
timestamp: March 06, 2022, 02:42:01 pm
content: Have you measured from component legs?I had once a bent leg.It was under the body and so close that measuring it made a contact.I found it with pure luck.Then measured it without making a connection and the force was so little that nobody does that unintentionally.Some been clear cracks in the middle of a joint and not something hiding in the edges but combined still so suitably that I didn't believe they are broken.Few I've found with cold spray but that is not very easy.Usually you believe you have found it but no, just some spray have been spilled.Then when you really find it a drop is a night and day.Few components I've changed since legs didn't connect anymore but those were power components and the situation was obvious.

author: 1audio
author_rank: Frequent Contributor
timestamp: March 09, 2022, 03:23:00 am
content: I got the 7403N running reliably. I don't knok which solder joint or trace I touched up fixed it but its fixed. I had inadvertantly popped the power supply and I thought it was a lost cause but it was just the HV fuse.The 5112 will be next and its probably a similar connection problem.
Tektronix AWG2005 frequency error - Page 1
Forum section: electronics / repair

author: oz7ou
author_rank: Newbie
timestamp: August 05, 2024, 07:56:42 pm
content: My AWG2005 has a constant frequency error such as when setting 10KHz the output is 16KHz. As the technical service manual has no schematics I would be happy for a hint where to look for the error.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 06, 2024, 05:42:47 pm
content: Have you looked at the waveform/changed load type/changed counter settings to verify that the 16kHz is actually what's coming out?It's pretty unusual to be that far off and not be a multiple of the frequency or something - I suspect the 16kHz you're measuring is an artifact from the combination of measurement/output settings or a symptom of a different fault.

author: oz7ou
author_rank: Newbie
timestamp: August 06, 2024, 08:19:45 pm
content: Thank you for your comments.I monitored a sinosoidal output with my TDS3054 Tektronix oscilloscope and it measure the frequency to be the 16KHzI must admit I do not understand how frequecies are generated based on the NVRAM modelskind regardsKurt

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 07, 2024, 02:24:43 am
content: if set it to 20 KHz, won't it be 26 KHz?It is possible that some offset value is set.
Tektronix AWG20xx power supply R174 value - Page 1
Forum section: electronics / repair

author: aeg
author_rank: Regular Contributor
timestamp: November 15, 2023, 10:14:59 am
content: Does anyone know the resistance of R174 in the Tektronix AWG2041's power supply? Mine is smoked - open circuit. Tektronix didn't publish schematics. The same power supply is also used in the AWG2005 and in AWG2021 S/N J300101-J320100.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: November 15, 2023, 08:20:46 pm
content: I see several other similar looking vertically mounted PCBs on that main board. Desolder those and see if the two working and non working boards have identical layouts. If so, look at the value of the resistor on the good one and you got your resistor value.While you're at it, check the other components to see if they are faulty or not. Resistors don't just burn out randomly. Something sorted in this PSU...

author: aeg
author_rank: Regular Contributor
timestamp: November 15, 2023, 11:18:58 pm
content: The board with the open resistor is different from any of the others. They all have a resistor in series with the 2SA1220A collector, but the values vary. I already checked the semis on the small board and none of them are shorted. There are two bad caps on the primary side but I can't see how they would cause a resistor in a postregulator(?) on the secondary to fail.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: November 15, 2023, 11:50:41 pm
content: In that case you can try to reverse engineer that PCB with the burnt resistor and create a schematic.Using this schematic, you can try and find possible values for that resistor.ei:If it's a pulldown resistor for a FET, generally nearly any resistor value between 10k and 50k would work fine.If it's a voltage divider that's meant to create a specific voltage, and you know that specific voltage it should output, you can calculate the value of the resistor.etc...Make an educated guess and choose the largest value and go down from there. Largest, to smallest resistance value.

author: aeg
author_rank: Regular Contributor
timestamp: November 18, 2023, 10:33:12 am
content: Thanks for the suggestion. I would prefer to wait and see if someone with the same instrument can tell me what resistor the factory installed.

author: gianrisa
author_rank: Contributor
timestamp: November 24, 2023, 11:59:02 am
content: Hey I hope this will help you the resistor is a 51 ohm here the picture !Let me know if you need any other values. I have my awg2021 open because I have a trouble on the chain Waveform Mem -> DAC, I don't know yet if the ram data is stuck or the ram address doesn't get selected correctly or the DAC is faultyI've discovered that the board A21 has all the D0-D12 clock and CE CS exposed there so my next try will be to connect the Logic analyzer there and check what's going on. I hope it is the ram and not the DAC, that will be quite hard to find it.Let's see.Cheers Gian

author: aeg
author_rank: Regular Contributor
timestamp: November 27, 2023, 11:58:15 am
content: Thank you Gian! I hope you get your AWG2021 working.
Tektronix AWG610 'performance check disk'? - Page 1
Forum section: electronics / repair

author: John_ITIC
author_rank: Frequent Contributor
timestamp: July 31, 2020, 04:30:21 am
content: Hello, I picked up a Tek AWG 610 on Ebay as a hobby restore project. It was listed as dead but now brought back to life.There is one error reported by the built-in calibration: Direct output: 'fail". The service manual states that the various voltages should be read on a DMM as output by pre-configured waveforms that are on the "performance check/adjustment disk" (floppy). Tek part number 063-A273-00. But that disk is nowhere to be found.Does anyone possible know where to find such a floppy disk?Thanks.
Tektronix Blue - Page 1
Forum section: electronics / repair

author: jdragoset
author_rank: Frequent Contributor
timestamp: August 19, 2019, 12:58:16 am
content: https://www.ebay.com/itm/Tektronix-spray-paint-Tek-blue/173821779378?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

author: med6753
author_rank: Super Contributor
timestamp: August 19, 2019, 10:55:16 am
content: And this is a close match that I've used several times and is readily available, much cheaper, and you'd be hard pressed to tell the difference.
Tektronix CSA7404 - Page 1
Forum section: electronics / repair

author: Scherer
author_rank: Newbie
timestamp: October 21, 2021, 09:40:37 am
content: Hallo,ich habe einen Tektronix CSA7404 mit folgendem Fehler:Das Gerät zeigt nach durchgeführter Diagnostik Misc 531 run cal an.Nach durchgeführter SPC (Signal Path compensation) Meldung Pass.Schaltet man das Gerät aus und wieder ein sind die SPC Daten verloren.Zudem zeigt das Gerät keine Seriennummer an.Wie oder wo werden die SPC Daten abgelegt-gespeichertKann hier jemsndd helfen ?Vielen DankHans Scherer
Tektronix CSA7404B OS and other software - Page 1
Forum section: electronics / repair

author: matthuszagh
author_rank: Frequent Contributor
timestamp: March 10, 2023, 07:04:10 pm
content: I'll be receiving a CSA7404B without a hard drive (and therefore no OS installed) in the coming days. I have a Tek TDS7104 with a working Windows 2000 installation. Will that work for the CSA7404B? If not, would I just need to supplement it with some applications and drivers? Where would I find those? If not, any ideas how to proceed? Thanks!

author: matthuszagh
author_rank: Frequent Contributor
timestamp: March 10, 2023, 07:56:50 pm
content: I downloaded a bunch of drivers and other software for the CSA7404B fromhttps://www.tek.com/en/search?facets=_templatename=Software&keywords=csa7404b&page=1. If using the TDS7104 disk doesn't work, my plan is to do a fresh install of Windows 7 (or maybe Windows 2000 if that doesn't work) and install those drivers and software as needed.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 10, 2023, 11:14:51 pm
content: if you have a win 98 or XP or win 2000 sticker on it, use the right windows, you may face incompatibilities with more recent OS

author: matthuszagh
author_rank: Frequent Contributor
timestamp: March 10, 2023, 11:29:28 pm
content: Quote from: coromonadalix on March 10, 2023, 11:14:51 pmGood to know. It's got a Windows 2000 sticker on it, which is also what my TDS7104 uses, so I'll use that.

author: mikehank
author_rank: Regular Contributor
timestamp: March 13, 2023, 03:38:50 pm
content: Hi,Aside from any OS related issues the Scope Application version is very different. The TDS7104 uses older style hybrid front ends and the TDS7KB uses preamps, Teledyne relays and more.

author: matthuszagh
author_rank: Frequent Contributor
timestamp: March 13, 2023, 09:23:36 pm
content: Quote from: mikehank on March 13, 2023, 03:38:50 pmI downloaded several versions of the TekScope application from the Tek website. They state the device compatibility and the versions I downloaded (2.7 and 3.9) include the TDS7104 and CSA7404B, along with a long list of other units, so it looks like the same version of the tekscope application covers a lot of scopes. Am I wrong?
Tektronix  Current probe DC Drift - Page 1
Forum section: electronics / repair

author: gogoman
author_rank: Regular Contributor
timestamp: August 25, 2021, 04:58:58 am
content: Hello I came across a TCP00030 Current probe. The probe has a DC drift of about 70mV, until it warns up. Once warned up it settles within several mV of the bassline of zero. Is the drift cause by a defective hall effect sensor, down stream electronic or a mechanical part in the handle?Any suggestions where to start.thanks

author: Hamelec
author_rank: Regular Contributor
timestamp: August 25, 2021, 08:02:38 am
content: nothing at all.But see instruction manual:"Quick Tip:To maintain measurement accuracy, degauss your probe in each of these cases:After you turn on the measurement system and allow a20-minute warm-up period"

author: gogoman
author_rank: Regular Contributor
timestamp: August 26, 2021, 12:37:44 am
content: An identical TCP drift 1-2mA at power up after which it locks on to the baseline settings. Which leads me to believe the drifty one has a problem .thanks
Tektronix DA4084  volt level problem  - Page 1
Forum section: electronics / repair

author: kirby64
author_rank: Newbie
timestamp: November 09, 2022, 04:53:04 am
content: Hi guys i got a tektronix DA4084 distortion analyzer this is the military version of the aa5001. I went thru the entire calibration procedure with no problems but for some reason when i measure anything above 13khz frequency the volt level reading accuracy starts dropping more than the + or - 4% stipulated on the specs once i make it to 20khz it only measures about half the value it supposed to read, once i go above 30khz all the way to 50 i have no reading any ideas where to start looking thanks

author: alanep
author_rank: Contributor
timestamp: November 10, 2022, 06:13:33 am
content: Hello Kirby64,A couple of things:1. What signal generator are you using for the freq. tests? I see in your previous posts that you were working on a HP8903, are you using that?2. The DA4084 has a 30KHz filter. Is that activated? Try cycling through the filter buttons & see if it changes.Beyond the above, it gets a bit harder to diagnose without more information.....Just a bit of speculation:There have been past instances with the AA5001 input attenuator reed relays misbehaving. I've also seen corrosion near where the wires enter the glass of input protection incandescent lamps. In both cases, one leg of the balanced input won't be internally connected through to its associated opamp circuitry. This will cause lots of problems including poor frequency response.The filters are internally selected via a 4052 CMOS switch, perhaps a filter is stuck on either because the 4052 input selects are incorrect or the 4052 is faulty.Because the AA5001/DA4084 module is plugged into a power frame, signal tracing/fault finding (with it powered) is a real pain without an extender. The alternative is to solder & run individual wires from the points of interest on the PCB.RegardsAlan
Tektronix deprecated free trial options - Page 1
Forum section: electronics / repair

author: Circuitauger
author_rank: Newbie
timestamp: April 26, 2024, 03:58:46 pm
content: Hello,Been needing to get some options onto my Tektronix TDS series oscope for some signal analysis. Found Tek still has the free trial & download of the software package option on their website, installed, everything works fine. The issue however is that unfortunately it seems that Tektronix no longer actually sells license keys and/or option keys for any of their older equipment.So currently I’m stuck just leaving the thing on so the number of remaining code launches doesn’t decrement to 0.Saw on the forums here there’d been discussion on hacking the scopes to unlock options, don’t know if I need to go down that road yet.Does anyone know how the remaining trial boot up counter works? Is it writing to some eprom, or can the hdd just be frozen in time from changes, or the trial software just indefinitely uninstalled and reinstalled?

author: colorburst
author_rank: Regular Contributor
timestamp: April 26, 2024, 10:27:15 pm
content: The TDS family consists of dozens and dozens of models. What scope, specifically, are you talking about here?

author: Circuitauger
author_rank: Newbie
timestamp: April 30, 2024, 02:38:59 pm
content: TDS6154C Running Win XP SP2

author: calibrationfixture
author_rank: Regular Contributor
timestamp: April 30, 2024, 09:37:53 pm
content: Hi Circuitauger,See:https://www.eevblog.com/forum/repair/tektronix-tds5054b-record-length/25/End of Thread.Calibrationfixture
TEKTRONIX DM5010 and FG5010 Switches Sticking - Page 1
Forum section: electronics / repair

author: cjuried
author_rank: Contributor
timestamp: October 14, 2023, 02:14:56 pm
content: Hi all,I have a DM5010 and FG5010 which have momentary pushbuttons that are sticking. Is there a recommended cleaning procedure to resolve this issue? Is this a known common problem with these modules?Thank you.

author: coromonadalix
author_rank: Super Contributor
timestamp: October 14, 2023, 04:49:26 pm
content: not common as the racal dana ones, but over time, since they are old systems,the switch components inside may degrade, i have an dm5120 who began to exhibit the same symptomsand finding substiutes .... some have leds inside them in my caseyou have to measure their heights and sizes ... and try to find similars onesuser manual and SV manual herehttps://w140.com/tekwiki/wiki/DM5010https://w140.com/tekwiki/wiki/FG5010

author: cjuried
author_rank: Contributor
timestamp: October 14, 2023, 05:57:43 pm
content: Indeed. However is there a cleaning solvent and/or lubricant procedure that has been shown to resolve this issue?

author: coromonadalix
author_rank: Super Contributor
timestamp: October 15, 2023, 01:55:58 am
content: deoxit can do wonder for oxidized contactsbut if the mechanical spring action is foam based or plastic dome / metal dome .... degradation / deformation over time can happenlubricant : i would not try to use them, you have to dry clean all contacts to be sure, deoxit them, let them dry, or use compressed air to move everything out and do some testspetroleum based lubricant could do more damaged than good, you have to use dedicated ones for switchs ??

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 16, 2023, 12:07:27 pm
content: In my AFG5101 IIRC I carefully removed the cap and cleaned the sticky ones with isopropyl alcohol them clicked the top back on.Was a while ago though, so I can't remember the details beyond that unfortunately.

author: cjuried
author_rank: Contributor
timestamp: October 17, 2023, 12:14:30 pm
content: Was it a disassembly of the front panel from the main chasis or were you able to remove the caps with the front panel attached? Thank you.Quote from: TERRA Operative on October 16, 2023, 12:07:27 pm

author: TERRA Operative
author_rank: Super Contributor
timestamp: October 17, 2023, 01:37:12 pm
content: It wasn't too hard to remove the front panel. A few screws on the top and bottom and the whole front assembly came away, then unplug a few cables and then remove the screws holding the PCB in place and it came apart.

author: cjuried
author_rank: Contributor
timestamp: October 17, 2023, 02:54:59 pm
content: I will give it a try. Thank you.Quote from: TERRA Operative on October 17, 2023, 01:37:12 pm
TEKTRONIX DMM 249 - Page 1
Forum section: electronics / repair

author: stfjohn
author_rank: Regular Contributor
timestamp: September 29, 2025, 10:36:06 am
content: Hi everyone.Does anyone know where I can find (even if it's paid) the schematics for the DMM 249 multimeter? Thanks.

author: MathWizard
author_rank: Super Contributor
timestamp: September 29, 2025, 12:00:03 pm
content: So Tektronix makes top of the line scopes, do they still make DMM's? Do they now own Keithley, and they still make their own DMM's ?

author: squadchannel
author_rank: Frequent Contributor
timestamp: September 29, 2025, 01:21:04 pm
content: DMM series(not benchtop) is a rebadged from a Taiwanese company.

author: edavid
author_rank: Super Contributor
timestamp: September 29, 2025, 02:08:52 pm
content: Quote from: MathWizard on September 29, 2025, 12:00:03 pmThe model OP is asking about came out around 1996, and as mentioned it was sourced from Taiwan (Escort?). I don't think the schematic was ever released.Tektronix made its own DMMs at various times, but without any consistency.QuoteYes, Keithley is part of Tektronix. That combined company does make (fancy) DMMs. Not sure of the relevance

author: David Hess
author_rank: Super Contributor
timestamp: September 30, 2025, 12:15:22 am
content: I thought APPA of Taiwan manufactured the old Tektronix DMM handheld multimeters. I looked through their current lineup and did not find anything close though.

author: MathWizard
author_rank: Super Contributor
timestamp: October 07, 2025, 05:37:03 am
content: Well is there a problem with the DMM ? It shouldn't take that long to make your own schematic, not the main parts anyways.

author: stfjohn
author_rank: Regular Contributor
timestamp: October 09, 2025, 10:48:52 am
content: The Volts and Amperes ranges work fine, but measuring resistances (ohms) gives random and incorrect values!
Tektronix DMM916 stuck on OL - Page 1
Forum section: electronics / repair

author: mainman
author_rank: Regular Contributor
timestamp: May 01, 2025, 06:21:02 am
content: Hello any advice would be appreciatedI have a Tektronix DMM916 handheld meter that displays OL on all functions, resistance, Dc Voltage (A and ma), Dc current, Hz, diode, etc. The fuses are good, the probe terminals are screwed tight. I took the unit apart and cleaned the selection knob contacts. I can't find schematics anywhere.Anyone have any ideals on this

author: coromonadalix
author_rank: Super Contributor
timestamp: May 01, 2025, 09:51:43 am
content: some similar teardown, possible resemblance to some modelshave you lost dial contacts or put back the dial incorrectly ?http://mrmodemhead.com/blog/tektronix-dmm912-teardown/other possible threadhttps://www.eevblog.com/forum/repair/tektronix-dm254-(service)-manual/

author: mainman
author_rank: Regular Contributor
timestamp: May 11, 2025, 02:34:59 am
content: Quote from: coromonadalix on May 01, 2025, 09:51:43 amI left out one important detail.All functions are in OL EXCEPT AC measurements. I can make AC measurements.I took it apart and cleaned all the contacts on the rotary knob. The fact that I can measure AC voltage tells me the input protection is not the issue. But I did check the input protection and as expected there was no component fault.

author: MathWizard
author_rank: Super Contributor
timestamp: May 11, 2025, 04:04:05 am
content: Not knowing the layout or anything, I can imagine a few things that could make most readings go off scale.I guess the cleaning the dial is a good place to start too. But I'd start signal tracing the input path, and see if it makes sense, before it goes off into some ADC.
Tektronix DP7054 SPC Fail - Page 1
Forum section: electronics / repair

author: vinovino
author_rank: Contributor
timestamp: September 30, 2024, 05:08:49 am
content: I'm encountering SPC Fail at my DPO7054.Does anyone of you know how to resolve this kind of problem?Firmware is already the latest Version 5.3.5 Build 22.Thank you.

author: colorburst
author_rank: Regular Contributor
timestamp: September 30, 2024, 06:04:27 am
content: Please provide more details. Any symptoms, failed tests, error messages?

author: vinovino
author_rank: Contributor
timestamp: September 30, 2024, 10:25:46 am
content: Please see images of fail SPC and diagnostics.

author: colorburst
author_rank: Regular Contributor
timestamp: September 30, 2024, 08:26:29 pm
content: I'd suggest taking a closer look at the ADCs. 225 indicates the software can't communicate with one of the ADCs; 343 is ADC-related as well. Not necessarily your problem, but we had seen those chips short out before:https://www.eevblog.com/forum/buysellwanted/fs-%28usa%29-broken-tektronix-dpo7104-%28adc-failure%29-for-parts-or-repair/
Tektronix DPO2024 Needs help - Page 1
Forum section: electronics / repair

author: 晓看风云
author_rank: Contributor
timestamp: November 18, 2023, 11:57:17 pm
content: I have a Tektronix oscilloscope DPO2024 that needs to be repaired, and it has always been very normal. Suddenly, one day, it started reporting errors and could not self calibrate. Every power on self test can pass, but when entering the system for self test, an error was reported, and I didn't understand what this error meant! Has anyone been exposed to these issues? If I don't perform self calibration, the waveform can be displayed on the screen normally, but after the self calibration fails, there will be no waveform left. If I turn it on again, it will be like forgetting the self calibration failure, and it can display the waveform normally! I have tried to open the channel acquisition module, but after rough measurement, it seems that everything is normal. The problem may be on the self calibration line. Can anyone provide some suggestions? Thank you very much！！！
Tektronix DPO30xx fails SPC, but why? - Page 1
Forum section: electronics / repair

author: dzseki
author_rank: Frequent Contributor
timestamp: March 02, 2023, 01:58:24 pm
content: At work we have a Tek DPO3034 (hacked to 3054), that fails SPC.The instrument has a serial starting with C01XXXX, on which the software bandwidth upgrade is not working theoretically, but in our case it did.In fact after the hack the SPC still ran fine, until one point, but not anymore. There haven't been any noticeable event to the scope why it shouldn't work, and indeed the scope works quite well as far as I can tell, but it fails SPC.Now, running SPC from the scope UI does not tell much information why is it not passing. Is there any way to see a detailed log at which step the procedure fails?

author: mikehank
author_rank: Regular Contributor
timestamp: March 02, 2023, 08:15:48 pm
content: You can put these scope into service mode by pressing the multi-purpose buttons on the right of the display. Press 1(top) then 3 twice and then 1 again. This will give you more detail as to your error.

author: mikehank
author_rank: Regular Contributor
timestamp: March 03, 2023, 12:04:47 am
content: A common failure for the DPO3K's is Nrej. This is fixed by putting metal tape all over the inner covers.

author: dzseki
author_rank: Frequent Contributor
timestamp: March 03, 2023, 07:02:07 am
content: Quote from: mikehank on March 02, 2023, 08:15:48 pmI tried this, but nothing happened, when exactly should I push these buttons?

author: mikehank
author_rank: Regular Contributor
timestamp: March 03, 2023, 06:08:49 pm
content: You may have to be in the utilities menu. I can't remember its been a number of years since I worked on these scope. Also some FW revs have different buttons to be pushed. Try holding button 1 then hold button 3 then push button two holding them all down
Tektronix DPO7104: all channels have high offset - Page 1
Forum section: electronics / repair

author: thefloe
author_rank: Newbie
timestamp: March 31, 2021, 08:10:35 am
content: Hi,Some time ago my DPO7104 failed to start and by exchanging the hard disk and disconnecting the cdrom drive I managed to get it up running again. Unfortunately there is one remaining problem: all four channels show an offset in the range of 200mV to 500mV and the offset is depending on the vertical range setting. The amplitude shown of the signal is correct. Also timebase is correct.I had the scope running over night, the offset do not seem to drift or change with time / temperature.SPC fails without showing much information and system diagnostics shows only a 412 code on the trigger system. Which relates to CH2.Any idea on how to get rid of the offset without sending this outdated model to repair / service?Thanks a lot,T
Tektronix DPO7254C Fails SPC, any suggestions on what to look for? - Page 1
Forum section: electronics / repair

author: antian
author_rank: Contributor
timestamp: December 08, 2023, 05:30:53 am
content: Hi, I am looking to repair a Tek DPO7254C that fails SPC, but the diagnosis and everything else passes and works well. Tektronix and some third parties charge an arm and a leg to repair and I cannot afford that. From discussions online and with people who have repaired them, it seems like it is likely something with the acquisition board. I plan to open it soon and look for leaking capacitors or anything obvious but does anyone have experience with possibly these scopes and common failures? I see some videos with relay replacement on the TDS series but I'm not sure if that may also possibly be the issue for this oscope.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 08, 2023, 11:26:57 am
content: you should had posted on the main tds 7000 series thread,you did not post the error codes and maybe you have an nvram battery failure, who's common in theses ...having this failure will give error codes in spc check, bad nvram config too
Tektronix DPO\DSA 70000 series Artesyn AFE 1200 Power Supply repair. - Page 1
Forum section: electronics / repair

author: smaultre
author_rank: Regular Contributor
timestamp: January 11, 2025, 12:50:52 am
content: Hello guys it looks that i acquired the scope fromhttps://www.eevblog.com/forum/testgear/tektronix-dpo70804-oscilloscope-and-acquisition-error-code-321theme.And i makes it works OK.No errors, and SPC is PASS.But after some hours of powered ON than shutting down witn WINPC, it randomly stops to turn ON.After some research a found that PSU Artesyn AFE 1200 goes to protective mode (red led).Now i'm diagnosing the PSU separatelly. Due to high cost of whole scope.And what i see:-after connecting to 110V line, its randomly goes into protection\failure mode.-if so it starts to operate about 0,8-1 sec and goes "red".- after that, when i quickly (without full cap discharge) re-connect 110V line it's starts, and works well like new.- when i wait 1 minute for cap discharging sometimes it starts, sometimes goes "red" state.Whats i'm already try:- to add capacitance on "hot" and "cold" side, check ESR all looks OK- ESR check capacitors on power FET's driver side is OK- ESR check capacitors on cpu/controller side is OKThis PSU is complicated maybe somebody knows the right diagnostic steps, or maybe you know these type of malfunctions?

author: squadchannel
author_rank: Frequent Contributor
timestamp: January 11, 2025, 01:14:02 am
content: bootstrap caps?

author: smaultre
author_rank: Regular Contributor
timestamp: January 11, 2025, 02:35:00 am
content: These are checked, there's no bootstrap caps, looks like a transformer -driven mosfets.

author: calibrationfixture
author_rank: Regular Contributor
timestamp: January 11, 2025, 08:14:15 am
content: Hi smaultre,The 3 Resistors (left from the Big Fat Fuse) don't look good. Color coding vague? Darkened PWB?Calibrationfixture

author: smaultre
author_rank: Regular Contributor
timestamp: January 12, 2025, 03:05:10 am
content: Yes,this resistors are powering stand-by & controller circuits.they looks like a load for the AFC stage they are OK

author: smaultre
author_rank: Regular Contributor
timestamp: January 17, 2025, 06:48:39 am
content: Hello, guys this time spent to find an adequate load. And i find a (1400)700W hairdryer..It starts every-time with this load without any troubles.But it not starts so smooth with scope hardware (scope hardware is 100% OK, tested with another PSU), i need to check 12V rail line now.
tektronix isolater a6902a - Page 1
Forum section: electronics / repair

author: xantia_99
author_rank: Contributor
timestamp: August 09, 2023, 07:08:17 pm
content: HiI got a Tektronix Isolator a6902a made in US serial number B0110686.I need the schematics.I got service manuals for a6902 and a6902B. But they differ a lot.Main board PCB 670-7806I can not find any useful at manuals plus.Thanks

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: August 09, 2023, 11:42:27 pm
content: I am not sure if one was made, service was handled by 1 or two centers at that time and I never found a manual for that model either.Jeff

author: TERRA Operative
author_rank: Super Contributor
timestamp: August 10, 2023, 04:43:12 am
content: Tekwiki has nothing, maybe try asking on the TekScopes site on groups.io

author: benj38
author_rank: Frequent Contributor
timestamp: August 10, 2023, 08:39:06 am
content: https://drive.google.com/file/d/1OX9DZS1Kpmmapu13tgeGiP3Vi62jXLOu/viewThis was scanned from microfilm a year ago by the wonderful guys at vintageTEK.org.The stated policy on their website is that once a manual is scanned by them they also send it to TekWiki, but it looks like they forgot to do so this time.

author: xantia_99
author_rank: Contributor
timestamp: August 10, 2023, 09:01:04 am
content: HiThank all of You for your response.I will look into it.

author: TERRA Operative
author_rank: Super Contributor
timestamp: August 10, 2023, 06:19:35 pm
content: I'll upload a cleaned up copy of that linked manual to Tekwiki in the next few days.

author: xantia_99
author_rank: Contributor
timestamp: August 10, 2023, 07:27:08 pm
content: HiVery good idea. That was one of the first places I looked at and was surprised it was empty.

author: TERRA Operative
author_rank: Super Contributor
timestamp: August 13, 2023, 04:59:03 am
content: Here you go, A6902A manual is all cleaned up, bookmarked and uploaded:https://w140.com/tekwiki/wiki/A6902
Tektronix MDO4104B-6 soft buttons not working. - Page 1
Forum section: electronics / repair

author: algavauser
author_rank: Newbie
timestamp: December 27, 2019, 04:06:54 pm
content: I am trying to fix a Tektronix MDO4104B-6 oscilloscope. The main problem is that the soft buttons in the front panel are not working. A new firmware was installed after the problems and that did not fix it. The oscilloscope does turn on when plugged to the AC. Also, the fan does not spin when turned on(even thought the source is providing the 12V and 5V to the main board), and test points all work except for the +1.5V test point. There was communication from the oscilloscope using the command app on my colleagues laptop. The front panel does light up , yet none of the buttons work (even the "on" button). Is there a way I can start tackling the problem? Thanks.

author: daveyk
author_rank: Frequent Contributor
timestamp: May 17, 2025, 08:23:49 pm
content: This is an old message, but 5 or 6 of the buttons on my Tek MSO4104, under the display are not working. Sometimes they do work.I have not opened it yet see of the PCB is cracked, or to clean the carbon pads. I hate to break the TMI calibration seals to get at them. Right now I can control it via the network port.The last time this happened, I was controlling it via USB. If it unplugged the USB cable those buttons would work fine. I will try unplugging the network cable. If that fixes it, then it has something to do with local mode. The MSO4104 does not have a local button, like other instruments do. Other keys do work though.Though software the scope does not let me assert local control, and error it returned.This is weird.
Tektronix membrane keypad fails - Page 1
Forum section: electronics / repair

author: luis garcia
author_rank: Regular Contributor
timestamp: November 26, 2020, 03:46:55 pm
content: Hi everybody,my Tektronix MDO3000 keypad is failing. It fails on some areas, for instance the RF numerical keypad.It is not totally dead; i maean, i can repeatpressing the key forever and it works eventually.Anyone exprienced solving this issue, please ?Regards.Luis.