hybridfree/eevblog-posts huggingface dataset:
Agilent 3458A 8.5-Digit Multimeter Repair, Teardown & IC Analysis - Page 1
Forum section: electronics / repair

author: Hugoneus
author_rank: Frequent Contributor
timestamp: April 19, 2024, 10:50:52 pm
content: You can watch the video here: [30 Minutes]youtu.be/VTocNUyGIWM** SPOILER **In this episode Shahriar repairs a faulty Agilent 3458A. These highly desirable multimeters have continued to climb in price in the past few years. The last time The Signal Path has repaired one of these units was back in 2018.This instrument generates several errors both during power up as well as Auto Cal procedure. The error points to a failure in the OHMS measurement mode. Detailed instrument block diagram and schematics are examined. Measurements also show incorrect DC current sourcing during OHMS measurements and the associated circuits are closely analyzed. The problem is traced to a quad-comparator IC. Replacement corrects all problems during ACAL. The battery backup of the SRAM ICs are also replaced to eliminate non-volatile errors. The IC of the comparator chip is also extracted and examined under the microscope.The repaired instrument performance is verified by using voltage, current and resistance standards.
Agilent 34970a missing input cards/water damage - Page 1
Forum section: electronics / repair

author: Laszlo
author_rank: Contributor
timestamp: September 04, 2020, 03:37:43 am
content: Hi.I found an agilent 34970A floating in a garbage skip. Suffice to say, the water didn't do any good to the transformer and there is also minor corrosion marks on both PCB boards. After spending two days cleaning and drying the unit it now almost look presentable, but the frame is still rusty in places and I can't seem to get rid of the corrosion around the relay pins on the internal DMM board.Does anyone know a magic trick to remove the rust of the frame, and also to clean the PCB of the residual corrosion?The unit now powers up without any issues but it displays an error due to the missing input boards/cards at the back. These were already missing from the unit, or sinked at the bottom of the skip and I couldn't find them.Quick search on the interweb reveals that the cards can be sourced, but these are rather pricey so I was wondering if there is a way to hack/bodge something at the back of the unit which would make it possible to try at least some basic measurements with the internal DMM.If someone have experience with this unit, or have a working input module and lives around East Midlands Uk please leave a message.Thanks a lot.Laszlo

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: September 11, 2020, 03:49:25 pm
content: Not sure if the errors would be caused by the input cards being missing, what's the code no?That's a nice find but I guess it didn't end up in the dumpster for no reason, I guess it failed somehow.How is the display, working fine? Even if you end up with parts, they are worth some money.And if you have DMM board inside... you're lucky, a lot of those machines came without this "option" and they are impossible to find.
Agilent 4155B error - Page 1
Forum section: electronics / repair

author: chilternview
author_rank: Frequent Contributor
timestamp: May 11, 2023, 09:37:46 pm
content: Anyone seen this? My newly acquired 4155B fails on power on self test, maybe once every 3 power cycles with an error 10907 which I gather from the docs means " Integrating type AD converter failed calibration or self-test. "The only workaround at the moment is to power down, wait a minute then power on again. But that may not work forever...
Agilent 4395A - Network Impedance Analyzer,  Power Supply repair - Page 1
Forum section: electronics / repair

author: djerickson
author_rank: Regular Contributor
timestamp: February 19, 2021, 01:14:35 pm
content: I'm in the process of repairing two broken Agilent 4395A - Network / Impedance / Spectrum Analyzers. Both have dead 24V power supplies.I repaired one by swapping in a different power supply. The other one, I was able to repair the supply. Next I'll try to repair the other one.For the gory details and some general advice on repairing power supplies with no documentation:http://www.djerickson.com/4395a-power-supply/Thanks,Dave Erickson
Agilent 4395A Repair Help - Page 1
Forum section: electronics / repair

author: RomDump
author_rank: Regular Contributor
timestamp: December 13, 2020, 01:07:16 am
content: Wondering if anyone has any experience repairing the A3 Tracking Source board (E4970-66503)?No block diagram in the service manual.Unit passes all Internal tests.It appears some DC voltage is leaking. It may be a common fault as e-bay sellers describing the same symptoms, (noise from 10Hz to 30Khz).I set the start and stop frequency to 10Hz and the waveform on the oscilloscope shows a spike and a notch.Doesn't show up on full spectrum.
Agilent 53132A - Page 1
Forum section: electronics / repair

author: RV066
author_rank: Newbie
timestamp: December 26, 2024, 05:56:08 pm
content: I own a Counter Agilent Model 53132A Opt. 010 S/N MY40008352.This counter has been presented to me several years ago.The counter is defective. The powerup self test indicates FAIL: QSPIThe condition of the counter is excellent.There are no scratches visible. It looks like a factory shipped item.I had the idea its now the time to try a repair.So I removed the cover. Inside the counter is no dust.I checked the supply voltages of the power supply.The output voltages are all present and within limits asspecified in table 2-4 of the Service Guide.The blower is operating.On the PCB of the power supply are no leaked electrolyticcapacitors visible.The signal on the 10MHz Out is present.I performed the self test routines of the Utility Menuby manual selection of the tests:Test ResultREV: 4613DISP? PASS(all segments of the VFD are visible andall LEDs of the frontpanel lights up)CPU? PASSROM? PASSRAM? PASSEEPROM? PASSGPIB? PASSQSPI? FAILFPGA? no result displayedFR ENDP? PASSMEAS? FAILINTERP? FAILKEYPAD? PASSPRINT? PASSWhen performing the QSPI test "QSPI: FPGA FAIL"is output on the RS-232 I/F.When performing the MEAS test" MEAS: Chan 1, measured too high FAIL "" MEAS: Chan 2, measured too high FAIL "is output on the RS-232 I/F. What is too high ?When performing the INTERP test" MEAS: Chan 1, measured too high FAIL "" MEAS: Chan 2, measured too high FAIL "" Interpolator: B, CC mode FAIL " is output on the RS-232 I/F.The PRINT test outputs the lines" "" HEWLETT-PACKARD,53132A,0,4613 "" !"#$%&'()*+,-./0123456789:;<=>?@ "" ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ "on the RS-232 I/F.As the DISP test and KEYPAD test are PASS I assume there is a failureon the mainboard.Is there anybody who knows which signal loops are tested whenperforming the QSPI test, the MEAS test and the INTERP test ?with best regardsReinhard

author: osmax_br
author_rank: Regular Contributor
timestamp: February 08, 2025, 09:28:47 pm
content: Have you found the problem?
Agilent 53151A Microwave Frequency Counter - Page 1
Forum section: electronics / repair

author: Marco_Mar
author_rank: Contributor
timestamp: January 27, 2024, 08:45:38 am
content: Hi Group,need your help, please.This unit is spot on as far as self-test and frequency measurement on both channels is concerned BUT it does not make any power measurements on channel 2.Whatever level (according to spec of course!) of power I fed in, the unit always read -42 dBm.Visual inspection inside the unit showed nothing remarkable.I could not find any help with this issue surfing the net. The service manual is utterly useless.Any hint?Many thanks

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 27, 2024, 04:06:58 pm
content: Did you find the CLIP?Schematics should help a little.I also added the available service notes, just in case they help...

author: Marco_Mar
author_rank: Contributor
timestamp: January 27, 2024, 05:55:30 pm
content: Thank you but my counter is 53151.Do you happen to have CLIP for this unit?Bye

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 29, 2024, 08:03:26 am
content: Ah, whoops... I've been playing with the 53131A/53132A/53181A instruments recently and totally misred the nunber....
Agilent 54621A Scope wont turn on.  - Page 1
Forum section: electronics / repair

author: bopstar
author_rank: Regular Contributor
timestamp: February 09, 2020, 07:21:45 am
content: I was working on some stuff with my Agilent 54621A scope measuring audio signals. and then I turned it off went to do something came back to turn it back on to find it wont turn on now.when i power the unit all the lights turn on but no display or anything.Attached is an image if anyone can help that would be great.

author: Prehistoricman
author_rank: Regular Contributor
timestamp: February 09, 2020, 01:52:37 pm
content: Do the buttons/lights behave as normal? I'm thinking that the display might be dead, but all the logic still functions.

author: HighVoltage
author_rank: Super Contributor
timestamp: February 09, 2020, 02:08:53 pm
content: Most likely the power supply is broken.This happens from time to time on Agilent scopes, older and newer types.Usually they are easy to repair or to replace the PSU.

author: EHT
author_rank: Frequent Contributor
timestamp: February 09, 2020, 02:26:32 pm
content: There is a Service Manual PDF which you'll be able to find. It has useful info such as how to test the main PSU and some other steps such as resetting the scope.However, it would be good to have the schematic as well. Anyone know where to find that? I have a 54622D which I'd like to have the schematic for.

author: fcb
author_rank: Super Contributor
timestamp: February 09, 2020, 02:26:36 pm
content: Does look like the CRT supply - do the buttons function as before? What's your level of repair-fu like?If you get stuck I've got a 54622A in stores that I can measure some voltages off etc..

author: JFJ
author_rank: Regular Contributor
timestamp: February 09, 2020, 08:29:01 pm
content: Before getting too embroiled in attempting to identify a hardware fault, do try a "key down power-up reset". This can often resolve 546xxx series oscilloscope boot-up problems. From the service manual:To reset the entire oscilloscope, press and hold any softkey and switch the oscilloscope power on. Release the softkey when the display appears.

author: bopstar
author_rank: Regular Contributor
timestamp: February 09, 2020, 10:55:21 pm
content: All the buttons never turn on in normal operation. some lights turned on that I didn't know where there which I thought was quite funny.Ill check the PSU as suggested.

author: bopstar
author_rank: Regular Contributor
timestamp: February 09, 2020, 10:56:54 pm
content: I did try pressing a softkey while turning on still behaves incorrectly with all the lights on. So sadly not the fix
Agilent 54621d Oscilloscope - Battery and Software buttons - Page 1
Forum section: electronics / repair

author: ErakWrizzard
author_rank: Newbie
timestamp: October 21, 2022, 07:23:08 pm
content: Hello i am a bit of an electronics newb and i just managed to pickup a 54621d. On startup it gives me a warning about low battery and the 4 leftmost software keys don't register when pressed. Otherwise it passes selftests and works with the calibration signal.For the battery problem i found this thread:https://www.eevblog.com/forum/repair/how-to-replace-battery-in-agilent-54621a-oscilloscope/But i couldn't find something for the software keys. It would be lovely if i could get some tips on resolving these issues. Thanks in advance.EDIT:Managed to find this video about the keys

author: ErakWrizzard
author_rank: Newbie
timestamp: October 22, 2022, 05:23:53 pm
content: I have fixed the buttons at least for now by disassembling the scope and cleaning the buttons with Isopropyl alcohol and then placing a bit of copper tape on top.
Agilent 54621D turns on but no CRT - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: August 02, 2019, 02:46:19 am
content: I am interested to buy an Agilent 54621D that power on and highlight some buttons, but has no display.I did read some posts here about this scope and seems there are quite a few people who did some work on those.Is it an issue anyone here has come across already?Most likely an issue related to the CRT control board? CRT coil?Or could it be something more complex like CPU not being able to boot up therefor not initialising the display?If CPU fails to boot would it likely highlight some buttons or not any?

author: Original
author_rank: Contributor
timestamp: August 02, 2019, 05:28:14 pm
content: Assuming that you have checked all voltages especially crt grid voltage (does the crt it light up?).After that check the electrolytic capacitors on the video board. They are notorious for failing (like mine). check the brightness pot for discontinuities.After that you could try to probe horizontal / vertical sync pulses and then for the video signal. Check out page 13 here:http://bee.mif.pg.gda.pl/ciasteczkowypotwor/HP/54601A_Schematics.pdfSchematic is for model 54601, but should be the same as yours.

author: gkmaia
author_rank: Frequent Contributor
timestamp: August 02, 2019, 10:34:56 pm
content: Quote from: Original on August 02, 2019, 05:28:14 pmI have no access to the scope prior purchase. But from what the seller told me it turns on but CRT do not light up.Really hard to do this troubleshooting based on guesswork.I imagine this is a digital scope so all probing signals go to a ADC then to the processor, then DAC to the CRT. Also the buttons in the front panel would only light up if the processor send the instructions to do so."By turns on" I can start to believe the main board and power board maybe fine.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 03, 2019, 12:14:27 am
content: Just don't pay too much for it... at worst, it can become a parts unit.
Agilent 54622 - 4 channels on digital acquisition stuck on low - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: October 10, 2019, 07:38:54 am
content: I got a Agilent 54622 that has an issue with the digital acquisition.Digital channels 2, 5, 6 and 7 are stuck in low.The acquisition circuit of each channel starts with a cap, then a resistor then the acquisition ASIC.Then probing these channels on the node between the capacitor and resistor or between the resistor and the ASIC the signal is killed and pulled to -4.5v.Has anyone come across this issue before or has some experience with these Agilent MSOs?

author: SilverSolder
author_rank: Super Contributor
timestamp: October 10, 2019, 12:26:36 pm
content: I have the same scope (but haven't seen the issue you are having).Suspect the ASIC is blown, as some of the inputs seem to be acting more like an output on your unit.Maybe swap the ASIC on the bad channels with its neighbour to prove the theory?

author: MarkL
author_rank: Unknown
timestamp: October 10, 2019, 02:06:13 pm
content: The 1NB4-5036 is an 8-channel comparator. Before concluding it's dead, I would try lifting a leg on the chip of one of the dead input channels to make sure the -4.5V is coming from it, maybe with a small load of 1k to ground.Someone is selling 1NB4-5036 on ebay for USD $6.95. It's also used on many of the 167xx logic analyzer modules if you know anyone with a dead module for salvage.

author: gkmaia
author_rank: Frequent Contributor
timestamp: October 10, 2019, 07:02:25 pm
content: Thanks guys. I just bought the ebay ASIC as it was just 6 bucks.I will let you know when it arrives is that was the issue.
Agilent 54622a Retrofit a floppy emulator drive - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: September 09, 2019, 05:40:47 am
content: i am trying to retrofit a floppy drive emulator to my 54622 and just getting disk drive error.Has anyone tried to fit one of these with success?Mostly confused with these jumpers. S1, MO, JE and JE. Not sure what to choose here. Cannot find a manual or datasheet.

author: magic
author_rank: Super Contributor
timestamp: September 09, 2019, 06:07:56 am
content: S1 may set the address of the drive. Move it to S0 or disconnect if there is no S0 position and see what happens.

author: BravoV
author_rank: Super Contributor
timestamp: September 09, 2019, 07:51:29 am
content: And bookmark this too, who knows you'll need this someday.->https://www.rudiswiki.de/wiki9/HxCFloppyDiskEmulator

author: gkmaia
author_rank: Frequent Contributor
timestamp: September 09, 2019, 07:57:17 am
content: Thanks for the feedback guys.I now understand a but better those two buttons. Seems they change between "floppy disks". The hard thing on my one is that is does not have a display so I am not sure in what disk I am after a press them once.Also...The files I saved on my Mac I can manage to see on the 54622.Bit the files I saved with the 54622 I can see them stored on my 54622, but cannot see them on my Mac.I also tried to load the firmware HxCFEUSB_V3_4_6_4a.UPD but not sure if it worked.
Agilent 54622D -- Missing "Intensity" knob. - Page 1
Forum section: electronics / repair

author: beavernuggetz
author_rank: Newbie
timestamp: June 14, 2023, 06:29:18 pm
content: Hello everyone,Need help sourcing and or figuring out how to go about replace a missing "Intensity" knob/button for a recent purchase of an Agilent 54622D.The original listing (eBay) showed the scope with the knob in question attached but when the package got to me the button was nowhere to be found and the seller claims he couldn't find it either. He refunded me $25 so it's all good since this knob is not used very much anyways.Having said that, it bugs me that the scope is not complete and aesthetically it is not pleasant to the eye this way.Anyone know where to source one? Have looked on eBay and thus far have come up empty.Already replaced the internal battery thanks to another thread on this forum where "hanakp" posted some very good pictures and information.Any information would be appreciated.

author: EHT
author_rank: Frequent Contributor
timestamp: June 14, 2023, 10:25:34 pm
content: Yes, I had the same problem with an eBay purchase. In my case it got snapped off whilst the seller moved/packed it and they were able to find and forward the missing part.The missing knob is on a long plastic shaft. On mine it wasn't possible to just glue the shaft as it was quite deformed. I got a small piece of aluminium tubing and used this to join the two parts. You may be able to find a NOS knob matching this, and then piece together an extension to the shaft. I think it just pulls out, so you get get some long nose pliers and pull out the piece you have. You might need a piece of tubing and a short replacement shaft.Obviously the easiest thing would be to buy a replacement of this plastic shaft, but I could not find this anywhere.QServiceare great but I can't see any knobs for these scopes here.Here's a pic of what it should look like & the part number. Also pic of my broken one.

author: beavernuggetz
author_rank: Newbie
timestamp: August 23, 2023, 02:46:01 pm
content: Wanted to say thanks for your response. It gave me some new insight about how to go about trying to resolve this.

author: yo0
author_rank: Regular Contributor
timestamp: October 08, 2025, 05:09:03 pm
content: https://www.thingiverse.com/thing:4609646Best regardsPio
Agilent 54622D question+E3615A - Page 1
Forum section: electronics / repair

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 14, 2020, 04:55:52 pm
content: Hello,It's me again with nitpicky question.I have 2 54622D scopes. On one of them battery should be replaced. And on that on which battery should be replaced during first power up i have noticed something which makes me concerned.So this is the situation:when i pust "quick measurement" key, on the left corner for a fraction of a second i can see a message "incomplete". Even when the signal is connected. If i push the key again no message "incomplete". Here you can see if watch a video carefully by pausing it:https://easyupload.io/t9cm2fOn the other scope which does not need battery replacement during first power up there is no message "incomplete" if i push quick measurement key. But when i push it and if i choose one of the options offered such as measure frequency i can see the message "incomplete, also for a fraction of a second and you can see it here:https://easyupload.io/3h218wBut you have to watch video by pausing it. So my general question is: is this behaviour normal or i should be concerned? Interesting, but i haven't noticed that before.I have a d*mn good eye and as i wrote above i am nitpicky...Also i have second question regarding E3615A power supply.Why during powering up the amp meter shows some values?You can see it here:https://easyupload.io/r0ycjnThank you guys in advance!Hrvoje
[SOLVED] Agilent 54622D strange error and garbled screengrabs - Page 1
Forum section: electronics / repair

author: luuk
author_rank: Newbie
timestamp: October 02, 2024, 07:37:54 pm
content: Hey people,I've recently installed a gotek floppy drive emulator in my Agilent 54622D.I used it to capture screengrabs before and it worked fine, but I suspect that after I updated to version A.02.31 (which is the latest software revision afaik) it stopped functioning properly. It gives a weird error on bootup every time the USB is inserted (see below), and the screenshots are garbled (TIF has shifts, and BMP has black lines).Has anyone here ever had this problem? I wonder if it's the software or the cable to the floppy emulator.

author: luuk
author_rank: Newbie
timestamp: October 15, 2024, 06:42:18 pm
content: I managed to finally fix this. I first beeped the cable between the GOTEK and my scope through and it turned out to be completely fine.Then I decided to check the FlashFloppy config file. I changed the optionwrite-drainfrominstanttorealtime. This fixed the garbled screenshot issue.However, the scope would still throw the error on boot. This was fixed by changing theejected-on-startupsetting fromnotoyes. I need to manually "insert" the floppy every time I reboot the scope now, but at least it doesn't revert to default settings anymore due to the error.I hope my woes can help someone else in the future!

author: KrudyZ
author_rank: Frequent Contributor
timestamp: October 16, 2024, 02:51:01 am
content: Which model of the Gotek did you use for this?Did you have to modify the front panel or did it come in the slim form factor?
Agilent 54622D timebase and trigger controls are a bit "jiggly" - Page 1
Forum section: electronics / repair

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 21, 2019, 04:11:38 pm
content: Hi!I have purchased from ebay 54622D scope and everything works fine except timebase and trigger pots/encoders? are jiggly.Is this possible to fix?Thank you!

author: SilverSolder
author_rank: Super Contributor
timestamp: May 21, 2019, 06:44:20 pm
content: I fixed mine by carefully spraying some DeOxit D5 into the rotary encoders. Completely stable now.

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: May 22, 2019, 03:58:45 pm
content: Thank you for your reply.I have contact spray by Kontakt Chemie.
Agilent 54622D trivia question - Page 1
Forum section: electronics / repair

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: March 06, 2020, 06:13:59 pm
content: Hello!So this is one trivia question which gives me a little concern about the scope.I have 2 54622D.On one when i power it up (nothing connected to the inputs) when i push "Auto-Scale" button i can hear for a brief moment sound comming from the floppy. On the other scope this is not the situation.So what i am concerned, is this normal behaviour? This is only at first powering up and as i push autoscale the floppy makes that specific read/write sound. And if i push autoscale again no floppy action.Thank you in advance!

author: EHT
author_rank: Frequent Contributor
timestamp: March 06, 2020, 08:45:01 pm
content: Just try putting a floppy disc in them and see if you can write waveforms, ideally test the saved images on a computer

author: oPossum
author_rank: Super Contributor
timestamp: March 06, 2020, 10:06:19 pm
content: Mine makes a sound when autoscale is pressed that does appear to come from the floppy. Only does it once after powerup.

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: March 06, 2020, 10:35:59 pm
content: Quote from: oPossum on March 06, 2020, 10:06:19 pmExact same situation is on mine! But only on one of 2 same scopes, so i have get my OCD kicked in because of that thinking that something is wrong. Are you sure that it comes from the floppy? Do not confuse it with sound of relayBut if it comes from the floppy now i feel reliefI don't know how to thank you for that

author: oPossum
author_rank: Super Contributor
timestamp: March 06, 2020, 10:54:37 pm
content: The relays always click - it's not that sound. It sounds like the floppy is seeking to track 0 but it is already there due to the powerup seek so it just makes a little clunk sound.Do you have the same firmware on both?

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: March 07, 2020, 12:01:20 am
content: Quote from: oPossum on March 06, 2020, 10:54:37 pmI am not sure about firmware. Will check tommorow.Best Regards,Hrvoje

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: March 25, 2020, 02:43:49 pm
content: Quote from: Hrvoje_CRO on March 07, 2020, 12:01:20 amHi again!The firmware is different.

author: oPossum
author_rank: Super Contributor
timestamp: March 27, 2020, 08:46:10 pm
content: Firmware on mine is A.02.31Available here if you want to upgrade both to the latest:https://www.keysight.com/main/software.jspx?ckey=1000000092%3Aepsg%3Asud&lc=eng&cc=US&nid=-32413.536882119&id=1000000092%3Aepsg%3Asud

author: Hrvoje_CRO
author_rank: Regular Contributor
timestamp: March 28, 2020, 01:50:40 pm
content: Quote from: oPossum on March 27, 2020, 08:46:10 pmHello,I have upgrade to the latest firmware yesterday and everything is ok.
Agilent 54624A CH2 out of calibration - Page 1
Forum section: electronics / repair

author: mr_rock
author_rank: Newbie
timestamp: July 27, 2022, 06:29:51 pm
content: Hello everyone - I have an Agilent 54624A oscilloscope that had been working fine for me for a while now, but Ch 2 is now wonky. Feeding the same signal into ch 1 and ch 2 and doing an auto-scale sets to two channels differently.CH1 CH2.jpgIf I do the same with ch 1 and ch 3, they are the same, same with ch 1 and ch 4.CH1 CH3.jpgI tried running a self-calibration, which failed on ch 2, leaving the status as:Stats.jpgI have gone though manually setting ch 2 and it acts the same. I have verified the probe attenuation setting is the same for both channels. I have the service manual - such as it is - which is quite limited, and offers no calibration / adjustment beyond running the self-calibration.As three of the four channels check out as good, I could just ignore ch 2, but I'd rather they were all working. If I can fix this myself, that would be my preference, but I'm not sure where to look next.Open to any suggestions.
Agilent 54810A infinium o'scope-sea searching some helps about the IC's details - Page 1
Forum section: electronics / repair

author: ln4007
author_rank: Newbie
timestamp: May 13, 2024, 04:10:46 am
content: hello everyone,recently i got the Agilent 54810A infinium o'scope,but it dad indeed with a lot of troubles,included powersupply out of workand and some stufs are short on the beforface board,finally i think i work out them beside the one that the IC of the ACQ board was lost.So everyone know what it is?And how can i make it work up again?Any replys well be appreciated

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: May 14, 2024, 06:33:12 pm
content: It looks like it's just an unpopulated foot print.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: May 16, 2024, 09:21:21 pm
content: Blown Up is absolutely correct. This is the same as my 54710, I just had it open. The missing chips are for the four channel models.These machines used different motherboards and different power supplies also. Makes working on it harder....

author: ARF
author_rank: Regular Contributor
timestamp: May 19, 2024, 02:21:14 pm
content: The author tells you that Timebase ASIC is missing. And this is a big problem. This is a custom HP chip.The topic starter, you need:Time Base ASIC 1SE6-0056 = 54810-89002 REV A = 54520/40 = 54810 /20 = 54835/45https://www.eevblog.com/forum/testgear/agilent-54845a-failing-all-trigger-self-tests/msg5460131/#msg5460131
Agilent 54820a  Infiniium system update files - Page 1
Forum section: electronics / repair

author: FPSychotic
author_rank: Regular Contributor
timestamp: August 04, 2025, 06:21:09 pm
content: Hi, I cannot find links to download the images to upgrade the scopes SO.I have vin.33 and 4.37.Does anyone keep the files or knows a place when find them?I would need 4.50 for.the original, and 4.30 for the SSD to upgrade to 4.50.I cloned the actual HDD in a SSD , (msata+adapter) but it is not working.Thanks.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: August 04, 2025, 07:33:54 pm
content: Try this thread toward the end....https://www.eevblog.com/forum/testgear/agilent-54835a-scope-(4-channel-1ghz-4gss)-repair-uphack/msg5452271/#msg5452271Did you partition the new SSD before cloning?Also this post:https://www.eevblog.com/forum/repair/hp-54810a/

author: FPSychotic
author_rank: Regular Contributor
timestamp: August 04, 2025, 09:56:45 pm
content: Thank you, will.check.the links, thank you.No , I made a copy bit to bit of.the disk, and I thought would clone the partitions or.anything.

author: Tony_G
author_rank: Super Contributor
timestamp: August 04, 2025, 11:11:02 pm
content: I think I might have answered this earlier...https://groups.io/g/HP-Agilent-Keysight-equipment/topic/114125485TonyG

author: FPSychotic
author_rank: Regular Contributor
timestamp: August 05, 2025, 08:22:44 pm
content: Thanks to Tony. I could update. I will use the 4.30 to recover once the SSD is installed.That was great. It looks I got the only one cannot be expanded up in Mhz haha.
Agilent 54820A Infiniium upgrade to 548x0A? - Page 1
Forum section: electronics / repair

author: FPSychotic
author_rank: Regular Contributor
timestamp: August 04, 2025, 10:39:25 am
content: Hi, I got an Agilent 54820A and checking the possible upgrades.Sadly I found different comments over upgrade 54820A t0 30A , and 30A to 40A.About my oscilloscope couldn't find if it can be upgraded to 30A/40A, does anyone knows?Does have these scopes software upgrades? As expanded signal analisys, protocols etc? Couldn't find anything ,no even a manual, it came a massive programming book, not clue for what.I'm new in bench scopes...
Agilent 54831M Hang, freeze, errors. [SOLVED] - Page 1
Forum section: electronics / repair

author: Cyclotron
author_rank: Unknown
timestamp: July 26, 2025, 02:49:31 am
content: I picked up a 54831M 600MHZ Agilent Oscilloscope for very cheap as the disk had failed. I rebuilt the disk with a make up of an IDE to mSATA adapter and an image I have. The system powered up and booted but it behaved very strangely. I only had 256M of memory in it so I waited till the additional memory I ordered arrived.Upgraded memory to 512M and it still had issues, it seemed when I messed with the ram the issues changed. I suspected the memory. After a long saga of wiggling, and inspecting I decided to reseat cables and cards.And this is how I discovered the actual problem. When I went to reset the video card and the ribbon cables on it, I went to detach a set of black wires and the connector came right along with the cable end. I've seen cold joints, I've seen parts that weren't even soldered but still touched. I've seen solder cracks.I'm posting this here in case others experience "Weird" behavior on one of these instruments. Maybe inspect this connector on your video card?
Agilent 54831M Repair - Page 1
Forum section: electronics / repair

author: ZGoode
author_rank: Frequent Contributor
timestamp: March 28, 2025, 05:14:47 am
content: Hello all,I tried to move my post asking about boot up from "test equipment" to "repair" but could not figure out how to. My 54831M does not seem to be able to get past the Infinium splash screen. It boots, but doesn't appear to load the menu. The keyboard I am using freezes up which makes me think something is wrong with the hardware possibly. I already tried reinstalling a fresh image using the recovery disk, but it lead to the same result as with the original image. I'm going to try a new drive, but at this point I think that is unlikely to be the problem.I tried putting the hard drive from my 54832B into the unit, which did boot to windows XP, but the buttons and lights on the front panel were completely unresponsive, which I am unsure if this is a driver or hardware problem due to possible hardware revisions between the Win95 and WinXP hardware. The unit does appear to have working inputs though, so at least the acquisition board appears to be functional.If I was to just say screw it and clone my 54832B drive for the 54831M, does anyone know which if any drivers I need to copy over from the recovery disk? And will they be compatible with XP?Any thoughts?
Agilent 54831m/b bracket identification - Page 1
Forum section: electronics / repair

author: Cyclotron
author_rank: Unknown
timestamp: January 17, 2025, 02:26:24 am
content: I picked up an Agilent 54831m at a decent price. It is very clean and in great shape. The issues I've found so far are that the scope board in the bottom had just about every screw loose and 2 were out and rolling around. I put all of those back and tightened them to factory spec but there was an aluminum bracket loose in bottom that I can't figure out where it went.I've attached some pics in case someone can tell me where it goes.Thanks!

author: Cyclotron
author_rank: Unknown
timestamp: January 17, 2025, 03:43:50 pm
content: Jeez, I don't know how many times I scrolled through the manuals looking for where this bracket went and didn't see it.For anyone that comes along looking. The attached image is where it should be installed.
Agilent 54831M/B ... calibration circuit not working - Page 1
Forum section: electronics / repair

author: leonpav
author_rank: Newbie
timestamp: March 09, 2025, 06:48:40 pm
content: Hi!I have an Agilent 54831M, where the calibration signal for the probe compensation does not work.In the service manual it says there should be asquare wave 715Hz signalpresent at the front metal tabs under the LCD. It's not there.I've probed around the calibration circuit, all the power supply voltages are OKAY, but I don't see any AC waveforms, except 10MHz on some ECL pins.This is the calibration circuit:Does anyone know, where the715Hz square wavefor the probe compensation comes from (which chip/clock is the source of this AC waveform)?The DC signal from the 16-bit DAC (-2.4V to +2.4V) is working OKAY.Thanks for help!

author: benj38
author_rank: Frequent Contributor
timestamp: March 12, 2025, 10:34:23 am
content: If you go to the calibration dialog box, and select the 715Hz calibration signal for the Aux output, do you get it there? Do you get the other signals you can select for the Aux output?This may help you trace and troubleshoot the problem.
Agilent 54845B won't power on - missing +15 BIAS - Page 1
Forum section: electronics / repair

author: DrNefario
author_rank: Contributor
timestamp: March 04, 2024, 01:36:05 am
content: I have an 54845B that won't power on. It has a Celestica 0950-4191 power supply which is very different fron the one in the 54845A scope. I am following the Power Supply troubleshooting section of the 54845B service manual. By using the 220 Ohm resistor to override the Remote Inhibit signal, I can get the unit to basically turn on the power supply, front panel, fans, etc. and the voltages on the power supply measure OK. However in addition to the inhibit signal, I have to cycle the connector P9 on the Fan board (remove and reinsert) to get to this state.I have measured all the resistances for the main power signals to ground and they are OK.I have determined that the 5 VSB signal is on (LED on PC-MB is lighted) when the AC power is connected and unit is OFF.The main thing that seems to be missing is the +15 V Bias signal. The service manual does not mention where this is generated and it is missing from the resistance check to ground table.The unit was working fine last week when it bacame unresponsive to the power button.I would appreciate it if anybody could help with any information regarding the +15 BIAS signal.

author: DrNefario
author_rank: Contributor
timestamp: March 04, 2024, 11:42:50 pm
content: More troubleshooting info - I was tracing the signals between the Fan Board and the Acquisition Board and measuring voltages. In the process of doing this I cycled the P9 connector on the Fan Board several times in quick succession as I thought I heard something like a relay clicking. After doing this maybe 5 or 6 times within less than 5 seconds the scope booted normally and presented the option to continue or run setup. So I ran the setup for the MB and set all options according to what the service manual said for the Motorola VP22 MB. Upon save and exit it started the normal scope mode and everything works normally. I even powered it off with the scope Power Button and was able to turn it back on - as long as the AC power cord was not interupted. It would not start again if the AC power was interupted and I had to "jiggle" the P9 connector again.I made all voltage measurements again when it was running and everything was in spec EXCEPT the +15 V BIAS line on the Acquisition Board which measures 5 VDC (as does the Rem inhibit TP). So it seems that the main power supply is OK and it appears that there is something wrong with the interlock inhibit path. It would be good to know what that test point measures in a normally operating scope.

author: m k
author_rank: Super Contributor
timestamp: March 09, 2024, 02:03:20 pm
content: Seems that 5VSB is for multiple positions and one has a capacitor that can't keep on from that direction.Maybe P9 is overloading and disconnecting it will allow that unknown capacitor load and release what it is blocking.No idea how +15V BIAS should be.
Agilent 6642A Overvoltage protection and other potential issues - Page 1
Forum section: electronics / repair

author: SebastianH
author_rank: Regular Contributor
timestamp: April 03, 2021, 04:17:14 pm
content: I recently purchased an Agilent 6642A power supply manufactured in 2012. Generally speaking it's in almost perfect condition. And at the first glance everything seems to work fine--the actual voltage (CV)/current (CC) is absolutely spot on (vs programmed value). The readback might be off by a few mV (I have to check more thoroughly though, could be mainly due to the limited resolution).But there is one obvious issue: As soon as the overvoltage protections trips (which it does at the programmed voltage) the SCR crowbar seems to engage properly. But there is a residual voltage of roughly 0.72V @ no load and a current in the 20mA range when shorting the output. According to the operating manual the voltage should not be there:QuoteSo I checked the relevant circuits (not neccessarily in this order) (Service Manual probably requires registration/mail address):https://www.keysight.com/de/de/assets/9018-01114/service-manuals/9018-01114.pdf):+-15 V, +5V Pass, haven't found specific values for RAIL+-, but should be fine+15 V ISUP is at ~13,5 V -> PassOvervoltage compare circuit: checked with scope just to be sure - triggers -> PassOutput bias/shutdown circuit: receives INHIBIT from secondary micro processor; receives OVSCR from GAN; resulting in SHUTDOWN becoming active; so the output bias circuit is shut down (+-15V Gated measure 0V, and the CONTROL line for the 7 output stages is very close to 0 as well) -> PassSCR circuit: Opto isolator sees OVSCR, SCR gate is driven to ~0.85VIf I simply disable the output (without OV protection triggered) I measure ~+0.7V on both +-15V Gated and 0.5V on CONTROL, but 0V at the output. I don't know what to make of it.I would appreciate any suggestion what to do/check next.I also observed that the transistors might not share the load equally. I measured the voltage drop at those 0 Ohm resistor "fuses" (F205, F206 and so on). At full scale (10A) I got something between 60 mV and 80 mV with the exception of XQ305, which was more like 120 mV. It seemed to get a bit hotter also (close to 70°C, whereas all others were more in the 65°C region), so I assume it might not be just a variation in resistance of the "Fuses". Maybe someone can shed some light on whether this is normal or not.And finally I read somewhere that the power supply considers the programmed CC value in downprogramming operation (second quadrant). Is this actually the case? Mine doesn't do that and I wouldn't neccessarily expect it to do so, because the purpose is not to operate the power supply as an electronic load, but to improve the response for voltage changes.BTW: If someone has a good solution for the fan noise issue please let me know. I'll probably go with a noctua fan + PWM control.Thanks in advance for any suggestion!Sebastian
Agilent 6643A producing a few volts when output is disabled. - Page 1
Forum section: electronics / repair

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: December 23, 2019, 03:38:12 pm
content: Hi community,On my 6643A, the output is delivering a voltage of a few volts (less than 7V) only when the output is disabled. However, once I enable the output, then the output voltage and current is tracking exactly on the spot with the programmed value, everything seems to work fine. Unit is set for Local sensing.For those who work with Agilent system power supplies, do you have any guidance on what to check for? I suspect there’s something wrong in the output stage bias/shutdown circuit in shutting down the bias voltage to the output stages, and to keep the supply output off.I thank you in advance for your helping hands.

author: Hexley
author_rank: Regular Contributor
timestamp: December 23, 2019, 04:37:39 pm
content: What happens to the stray output voltage when you have a load attached -- say, a 10-ohm resistor?Or if you feel brave, what if the output is shorted to ground through a beefy ammeter -- then what is the short-circuit current?
Agilent 6811B AC Source repair - Page 1
Forum section: electronics / repair

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 19, 2025, 05:49:32 pm
content: Hi group,I am going to share a few details on the repair of 6811B AC source.Basic specs:– 0-300 VAC– 375 VA– 3.25 A– 0-1000 Hz– rms, DC, AC + DC voltage and current– Peak voltage and current– Real, apparent, and reactive power– Harmonic analysis of voltage and current waveforms providing amplitude and phase up to the 50th harmonic– THD (total harmonic distortion)– Triggered acquisition of digitized voltage and currentThis is the a reduced power version of the AC source that was shared by TheSteve in this thread:https://www.eevblog.com/forum/repair/agilent-6812b-ac-source-repair/msg3754565/#msg3754565The information provided by TheSteve turned out to be very useful to me.Condition receivedI bought the 6811B locally in the southern Ontario region of Canada. The unit came with an old RIM (Blackberry) asset tag. From the condition it looked like it had been in storage for a while.Internal examinationInverter assemblyThe fuse installed in the unit was a glass fuse. It was visible that this fuse has blown.The inverter assembly was removed from the unit and semiconductors were checked. The damage pattern is similar to that reported by TheSteve in his 6812B. I ordered replacement parts from Digikey. The four MOSFETs and two Schottky diodes were around $45.00 USD.In addition to the damaged components, some of the connections in the PCB were fused. I had to replace some the missing connections with copper wire. The was visible 'blisters' on the PCB were this happened.More damageWhile testing the unit there was a loud crack and flash from a tantalum capacitor located on the Output Board.I removed the Output board and replaced the tantalum capacitor and the one next to it with 10uF 50V low ESR electrolytic capacitors.Error 70The FAN was running full speed and the unit would start with error 70, 'Fan voltage failure'. This was fixed by replacing U980 on the control board.Input coverThe 6811B came with the standard Agilent safety cover on the input. I designed a new cover the has an IEC socket. I have shared the files here:https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg5983371/#msg5983371After the repairI need to find a couple of knobs.Regards,Jay_Diddy_B

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 23, 2025, 02:01:42 pm
content: Hi group,I created knobs using a 3D printer.More information on the knobs can be found here:https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg5987677/#msg5987677Regards,Jay_Diddy_B

author: TheSteve
author_rank: Unknown
timestamp: July 23, 2025, 03:11:36 pm
content: The knobs look great!
Agilent 6813B Power Source / Analyzer defective (CC) - Page 1
Forum section: electronics / repair

author: Quester
author_rank: Newbie
timestamp: July 18, 2024, 05:04:49 am
content: Hello,short question, since I am at the very beginning of the process:I got here an 6813B Power Source, that was from someabandoned storage.Many functions where out of Spec, an initializing andre-adjustment solved most of the problems....But CC-Mode is not working!No matter what current I key in, the device will limitthe output-current to a much lower value than desired (1/3 or lower)(but with higher current-limit keyed in, the current rises).As said: it's calibrated/adjusted (by the way: the reading/measured valueon the Display is the actual floating current, so that is right).Since I do not have the adapter service kit 5063-2330 and have much respectregarding the high voltages inside I don't want to startfault-search from the scratch (but will if to other way)and I am hoping someone out there might know:"Yesssss, I know - it's common, it's cable/part xyz..."Error routines ending with "0".Looking forward for some hints.Thanks and best regards.