Agilent 54845A Failing all trigger self tests - Page 1
Forum section: electronics / testgear

author: TRN
author_rank: Unknown
timestamp: March 28, 2018, 07:24:57 pm
content: A while back I bought a 54845A on an auction, and this scope had one bad channel, due to a faulty ADC-Hybrid.So I bought a used one, and installed it in the scope, and the bad channel is now O.K.However the scope fails all the Trigger self tests.I recovered the scope software to (V4.30) which appeared to have fixed the problem, but when I then upgraded to V4.50, the problem reappeared.So I did another recovery to V4.30, and this time it did not fix the issue. A subsequent upgrade to V4.50 did not change anything.Can Anybody give me any clues as what the problem is.I have attached a PDF which shows thState Trigger, Pattern Trigger, Logic Trigger and Trigger level errorsThanks

author: 0xfede
author_rank: Regular Contributor
timestamp: March 28, 2018, 08:17:13 pm
content: Hello TRN,I don't know if this is your case (and I never had this scope) but I remember that there is a nice video from the Signal Path concerning the repair of a 54845A:Basically he find that poor contact between hybrids and the custom socket was causing intermittent faults.Hope that helps you.Best,0xfede

author: Tony_G
author_rank: Super Contributor
timestamp: March 28, 2018, 08:41:46 pm
content: I think you have a software configuration problem - The 54845A shouldn't see those tests in the self test menu - You should only see "Knob and Key", "LED" & "Scope Self Tests" in that menu.Try completely reinstalling the initial image - Did you get it from my OneDrive?TonyG

author: TRN
author_rank: Unknown
timestamp: March 29, 2018, 07:49:29 am
content: 0xfede,Thanks for your input, and the link for the video, and i have already seen this one, and have cleaned the hybrid contacts.This did however not solve the issue.

author: TRN
author_rank: Unknown
timestamp: March 29, 2018, 08:08:48 am
content: Tony_G,Thanks for your input, and if I do not mark the service extension box, I get the standard test menu which you mentioned.However when I do mark the box, I can test all the subsystems separately. I have attached a screenshot of the successful standard self test after the first recovery of the v4.30 software.I downloaded the v4.30 recovery and v4.50 upgrade software from the Keysight ftp, so I assume it should be O.K.Nevertheless I will download your version, from your onedrive, and will do a complete reinstall.I will let you know how it goes.Regards

author: TRN
author_rank: Unknown
timestamp: March 29, 2018, 11:00:38 am
content: Tony_G,I tried to locate your OneDrive, but I can't find it.Can you please send me the link?Regards

author: TRN
author_rank: Unknown
timestamp: March 29, 2018, 11:10:24 am
content: Tony_G,Just forget my previous post, because I found the link. (https://1drv.ms/f/s!Amqar8_XQ9Uzj6YhN1xHdM8tQdKMOA)Regards

author: Tony_G
author_rank: Super Contributor
timestamp: March 29, 2018, 02:53:02 pm
content: You're right - I missed the service extension checkbox - I still think that the unit might be thinking it is a MSO though so reinstalling per the Agilent documentation is worth a try. - I did a video on it here:https://youtu.be/L49qug1oGuohttps://youtu.be/x9FUXcWENoUTonyG

author: TRN
author_rank: Unknown
timestamp: March 31, 2018, 07:00:08 pm
content: Thanks for the video, and I looked through my stuff but I didn't have an IDE CD-Rom on the shelf anymore, so I have ordered one, and should get it next week.I will let you know how it goes.Regards

author: nctnico
author_rank: Super Contributor
timestamp: March 31, 2018, 07:24:23 pm
content: I tried to run the same tests on my 54845A (uphacked) but it passes all trigger test. I don't think your problem is a software issue because the errors don't refer to logic inputs. I suggest opening the scope and check the acquisition board carefully for bad solder joints. In my 54845A I found a chip which had come loose from the board!This is the thread I started:https://www.eevblog.com/forum/testgear/agilent-54835a-scope-(4-channel-1ghz-4gss)-repair-uphack/msg1251605/#msg1251605This guy also has quite a bit of info on the internals and I recommend to check all the power supply voltages:http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/

author: TRN
author_rank: Unknown
timestamp: April 04, 2018, 02:20:34 pm
content: Thanks for the advice, and I already checked the board for soldering flaws, but it is quite possible that I have overlooked a bad soldering joint.Anyway, i should get the IDE drive latest by friday, and if restoring the firmware doesn't work, I will do another check.Regards

author: TRN
author_rank: Unknown
timestamp: April 30, 2018, 07:06:29 pm
content: Hello Tony,It took a bit longer then expected because the HDD went defect, and I had to buy a new 40GB IDE drive. I burned a CD from your 5484xBRecovery.iso file (inside directory\54845\548xx\Upg_Rec\5484xB\) but the iso file is corrupt.So I used the v4.30 recovery and v4.50 upgrade software which I previously downloaded from the Keysight FTP.The result is the same meaning that none of the trigger events passes the self-test.So I followed nctnico's advice and have checked the board for any soldering flaws, but haven't been able to find any so far.I also read the article from dasarodeigns.com, (thanks for the link nctnico)I checked all the Voltage regulators and except forXU5 and XU19, they all match the values listed.XU5 and XU19 measure respectively +7.09V & +7.12V instead of +8.5V, but I don’t think that this interferes with the scope functionality, because it looks that they only supply power to the two large cooling fans.I also checked the attenuator connector pin-outs, and there some differences with the values listed.J7 & J9:Pins 20: (+ 1.61V with attn installed); (+1.71V w/o attn installed)Pins 16: +0.845VPins 8: (-2.78V with attn installed); (+1.8V w/o attn installed)J6 & J8Pins 20: (+ 1.61V with attn installed); (+1.71V w/o attn installed)Pins 8: (-2.78V with attn installed); (+1.8V w/o attn installed)Pins 11: +0.845VPins 16 from J7 & J9: and Pins 11: from J6 & J8 are all fed from the same regulator U45 which is an LT 1086. which outputs + 0.85V, so I am puzzled how can it be that one should measure +3.9V? on pins 16 & 11?any ideas are welcome

author: nctnico
author_rank: Super Contributor
timestamp: April 30, 2018, 07:43:34 pm
content: In the software directory your can find various help files. Look for HP4XS.HLP. This contains some information on how to diagnose the scope at the board level. It isn't a complete service manual but it might contain enough information to get you in the right direction.

author: Tony_G
author_rank: Super Contributor
timestamp: May 01, 2018, 12:01:41 am
content: Quote from: TRN on April 30, 2018, 07:06:29 pmDatasheet for that LT1086 ishere. Can you confirm that it is really supposed to be 0.85V? That doesn't seem right as that part is supposed to have a 1.25V different between Vout and Vadj. What are the R values for voltage divider on that part?TonyG

author: TRN
author_rank: Unknown
timestamp: May 01, 2018, 07:32:00 pm
content: nctnico,Thanks for the tip, however I have a hard time finding the HP4XS.HLP file on the scope, I also tried to extract the file from the Ghost image using GhostExplorer, but I was unable to do so because GhostExplorer crashes every time I try to extract anything,Can you send me a copy?regards.

author: TRN
author_rank: Unknown
timestamp: May 01, 2018, 07:53:47 pm
content: Tony,Thanks and you were right, about the regulator.The divider values are R1= 120 ohm; R2= 260 ohm. This means the regulator is set to output 3.96 volt, and I check Uout across the divider network, and the output is 3,96v. R2 however is not connected to ground, but to a node which is at -3.1v from ground, so that's why I am measuring 0.85v between the regulator output and ground.In a nutshell, the regulator is O.K., but I still am unable to figure out how can it be that one should measure +3.9V? on pins 16 & 11?

author: nctnico
author_rank: Super Contributor
timestamp: May 01, 2018, 08:15:28 pm
content: Quote from: TRN on May 01, 2018, 07:32:00 pmSee attachement:

author: Tony_G
author_rank: Super Contributor
timestamp: May 01, 2018, 08:27:42 pm
content: I find it interesting that there is supposed to be a -3.1 rail and you're reading 0.8 instead of -3.9.Might be a simple coincidence but it might be an indication of something wrong with the rails. Is pin 16 meant to be the -3.9v rail? I believe that it is but I've never checked on my scope (I had issues with the attenuators but not the power supplies).Pity we don't have a schematic.TonyG

author: TRN
author_rank: Unknown
timestamp: May 02, 2018, 06:19:23 pm
content: nctnico,thanks for the help file, now I only need to find a PC which runs Win XP or 7Tony,Thanks, and according to Matthew Dasaro, pin 16 is the -3.1v rail for the analog Hybrid. I will do some more board probing to see if this correct, and if I can make some sense out of this.Anyway, I agree with your comment about the schematics, and I really do not understand that these are not available somewhere. I mean HP/Agilent designed this scope, so they must have had the schematics.I am quite sure that there is a retired HP design engineer somewhere who has the whole documentation package laying on his desk with a pile of dust on top of it.Anyway I will get back once I have any news

author: TRN
author_rank: Unknown
timestamp: May 09, 2018, 02:46:45 pm
content: I am still trying to fix the the trigger self-test errors, and I am looking for the pin-out of Motorola MC10H105 and MC10H117 Ic's in a PLLC-20 case.The ON Semiconductor datasheets only show the pin out for 16 pin dual in line packages.Can anybody tell me where I can find the ones for the PLLC-20 case?

author: MarkL
author_rank: Unknown
timestamp: May 09, 2018, 04:48:59 pm
content: There's a standard conversion for pinouts between ECL packages. See attached.The full app note is here (good reading if you're interested in ECL design):http://www.onsemi.com/pub/Collateral/TND309-D.PDF

author: TRN
author_rank: Unknown
timestamp: May 10, 2018, 08:53:19 am
content: Mark,Many Thanks

author: rickells
author_rank: Regular Contributor
timestamp: April 16, 2019, 12:55:42 pm
content: hi,My Agilent 54845a has Trigger self-test "Failed" on all three of the Trigger tests; for all 4 channels.The scope does power On & can measure the Sq. wave signal from the Aux Out, & other signals Ok, (with knobs twiddled manually).It passes all of the other self-tests, .... just Not any of the 3 Trigger tests.I have cleaned the ADC's, examined the Acq board for solder/IC placement issues, but see none.Over the years there have been a few individuals who had the same issue (JayW, JWalling, TRN) & perhaps others, but details seem not to be found...TRN seems to have started to examine voltages & signals ...somewhat difficult with no schematics in the service manual.1) -- How was this Trigger problem fixed ??thank you,rickPrevious references to Agilent / HP 54845a & 54831b or 54832b Trigger problem:https://www.eevblog.com/forum/repair/sometimes-knowing-what-something-means-is-half-the-battle-agilent-54831b-error/msg1008382/#msg1008382https://www.eevblog.com/forum/testgear/agilent-54845a-failing-all-trigger-self-tests/https://www.eevblog.com/forum/testgear/agilent-54835a-scope-(4-channel-1ghz-4gss)-repair-uphack/https://www.eevblog.com/forum/repair/agilenthp-54845a/msg1267378/#msg1267378https://www.eevblog.com/forum/testgear/agilent-54831d-modernising/https://community.keysight.com/thread/6575https://community.keysight.com/search.jspa?q=54845ahttps://community.keysight.com/message/15068http://www.dasarodesigns.com/projects/fixing-an-hp-agilent-54845a-infinium-oscilloscope/https://wonghoi.humgar.com/Hobby.htm

author: Alfons
author_rank: Regular Contributor
timestamp: November 08, 2019, 09:33:04 am
content: If you're still interested: I've upgraded a 54815 to a 54825. After that, the device wanted a recalibration. All channels showed Trigger Fail. After a long search, I found this thread:https://www.eevblog.com/forum/testgear/_fdc-failure_-on-scope/and the contribution of free-electron:Quote from: free_electron on May 12, 2013, 07:35:58 pmThe device ran for an hour before the test. And I also ran the ProbeCal for all channels before the calibration. That worked then. All channels could be calibrated without error.But also before I had let the device warm up. I think that's actually a software bug in many cases when all channels report Trigger Fail.

author: ARF
author_rank: Regular Contributor
timestamp: April 16, 2024, 07:41:52 pm
content: The same scope, the same problem.As soon as I received it, I did a self test and the self test passed well.After that I tried to do a calibration - but the calibration failed with an error on channel 3.The next day I decided to repeat the calibration, but I received errors on all channels.I did the self-test again and it already failed with 4 trigger errors.

author: ARF
author_rank: Regular Contributor
timestamp: April 17, 2024, 11:31:13 pm
content: So... I started studying the acquisition board design and ran into a rather stupid problem. The board contains a lot of logic manufactured by Motorola in PLCC packages. However, when I downloaded datasheets for some ICs, they did not have a description of the pinout for the PLCC housing. Quite strange.https://www.mouser.com/datasheet/2/308/MC10H105-D-21730.pdfI assumed that the pinout would be the same for the DIP and the PLCC, but it appears that this is not the case. There are no data for the PLCC. Maybe I'm too tired and need to sleep...

author: MarkL
author_rank: Unknown
timestamp: April 18, 2024, 12:39:48 am
content: Look back in this thread to Reply #20 on May 09, 2018, 12:48:59 pm. You will find the pin mapping.

author: ARF
author_rank: Regular Contributor
timestamp: April 18, 2024, 03:36:48 pm
content: The fact that the guys have not been able to solve this problem for many years is a completely disappointing. I'm not smart enough.However, I found an interesting thing that I did not see on the forum (or I missed it). Like many others, I have an error with all triggers, including Logic Trigger.According to the internal help, Logic Trigger is easy to test; it is sufficiently isolated from other blocks of the ACQ board.I did the Logic Trigger self-test separately and the first error I received was: "Logic trigger memory test is failing".The help says:"The logic trigger memory is tested by writing out test patterns to all setable bits accessible over the serial IO port, reading data back in and comparing all setable bits. The two test patterns 0xAA and 0x55 are used. Not every bit of every word is writable. Fifty bytes of the sixty-four byte memory are tested."This means that the error is completely digital! Between the PCI board and the ACQ board. Serial data is not written(?) to the memory registers of the Logical Trigger.The help says:"The logic trigger self test includes tests to check the integrity of the serial data port, the startable oscillator which includes parts external to the logic trigger IC and a group of tests which are contained entirely inside the logic trigger IC except for circuitry to read and write from the serial port. The logic trigger self test consists of 11 separate tests listed and described in order of execution:"It shows how to check these dependencies:"The logic trigger test is somewhat self contained but does depend upon the serial input port and the 100 Mhz startable oscillator. The startable oscillator is used for pattern duration and range.To check the 100 Mhz startable oscillator:1. Check the enable line toggles during the test. U84 pin 152. Varify that the oscillator is running during the test. U84 pins 18,19The logic trigger also provides holdoff for the trigger system. A 50 Mhz free running oscillator is used as the holdoff clock.1. Verify that the 50 Mhz osc. is running. U81B pin19"Everything that is described is present on my board: turn-on signals, 100 MHz, 50 MHz. This brings us back to the digital problem.Now comes the fun part. Where is this chip with internal memory located on the board?Considering that I see turn-on signals and clocks during the test, the problem is most likely with reading from this digital interface. It looks like the registers are being written correctly.

author: ARF
author_rank: Regular Contributor
timestamp: April 18, 2024, 05:05:30 pm
content: Presumably this is so, but there are probably errors there.

author: ARF
author_rank: Regular Contributor
timestamp: April 20, 2024, 11:00:06 pm
content: So.. go to the next...Where is the Logic Trigger IC?I found this thread:https://community.keysight.com/forums/s/question/0D52L00005Idye3SAB/54835a-self-calibration-errorQ:I have a 54835A 4 channel scope ( VIN #033 Rev. A.04.30.) The scope works fine , performance tests and all self tests are fine . If i start the self calibration from the UTILITY menu , vertical for all channels is pass but trigger for all channels is fail .The error details are : Logic Trigger Duration, Logic Trigger Delay, Main Trigger Treshold Delay, Main Trigger Runt Delay, Main Trig Time Qual Runt DelayA:This indicates that the Logic Trigger IC on the Acquisition board has a problem. Normally I would recommend replacing the Acquisition board and this would solve the problem. The problem with that suggestion is there are no replacement boards. These boards had to be discontinued early because a lower level part ran out of supply.My gut feeling is the Start able Oscillator has stopped running1FJ9-0002 is the Logic trigger part, and you might see I the crystal is running that is next to that IC. I am sure you could replace the crystal, but if it the Logic Trigger IC then that is big trouble.This support person looks like he knows what he's talking about. He has internal docs. The only problem is that I don’t remember the 1FJ9-0002 component on my board.https://www.ebay.com/itm/224709823013I googled the component and found a link on ebay. This is a ceramic custom chip.On my 54845A board there are 2 small square boards installed, on which some kind of logic is located on custom “JAPAN 1821-4786” chips. It looks like a regular board with a regular mounting density. It seemed strange to me that this was done on a separate adapter board, and not on the main board right away. Now I have a theory. This adapter is a replacement for the 1FJ9-0002 ceramic chip. Perhaps at the very first revisions there was a ceramic chip, then a problem arose with production and it was replaced with a cheaper option. Pay attention to the pin pattern - it looks like a pattern for a chip. I haven’t yet found a photo of the 54810 board from the back side to compare.Notice how similar the components around the Logic Trigger are on the 54810 and 54845 boards.UPD:I was right. This must be a direct replacement. Look at the last photo.https://www.ebay.com/itm/224709823013https://www.ebay.com/itm/126311386857UPD2:The further, the more interesting. I found this thread and a mention that the 54520/54540 uses the same Logic Trigger chip. Moreover, I checked that the Time Base chip is the same!https://www.eevblog.com/forum/repair/hp54520-logic-trigger-problem/This means:Logic Trigger ASIC 1FJ9-0002 = NO NAME??? = 54520/40 = 54810 /20 = 54835/45Time Base ASIC 1SE6-0056 = 54810-89002 REV A = 54520/40 = 54810 /20 = 54835/45The photo of the 54520 board has a rather familiar picture.https://damien.douxchamps.net/elec/equipment/hp54542a/battery/https://damien.douxchamps.net/elec/equipment/hp54542a/onboarding/And now we have a block diagram that can be applied to the 54810/54835, which is nice.https://www.keysight.com/br/pt/assets/9018-05775/service-manuals/9018-05775.pdf

author: ARF
author_rank: Regular Contributor
timestamp: April 22, 2024, 07:26:37 pm
content: Let's continue...I was right, it's a digital problem.After it became clear where to look for the Logic Trigger IC, I looked for and checked the digital interface. In this case, I was just lucky and didn’t have to search for long. On the LT substrate there is a TTL - ECL translator U1 100324 (https://www.mouser.com/datasheet/2/308/100324-1190082.pdf). This is the data input for the LT ASIC. On one of the bits, I noticed strange signals in some parts of the data block. Sometimes (not always!) the logical 0 of the input signal was about 1.57V and had a slight ringing. 1.57V is an undefined state for the TTL logic. Because of this, sometimes a logic 0 was converted by the 100324 chip into a false signal sequence. This always happened on a specific input data pattern.If someone is looking for this problem, then I advise you to stop the scope, select “trigger group” or "logic trigger" in the self-test menu and run the self-test every time to catch the digital signals for the LT.Then I looked where logical 0 was lost. This bit is connected via U166 SN74ALS273 (https://www.ti.com/lit/gpn/SN74ALS273) to the common data bus. U166 is used for data bus arbitration. You can see that the data bus itself does not have a very nice signal, but this is not a defect. I'll write about this a little later. U166 must set the output by the edge of the clock and we should have a clean signal on the output. Instead, I see copying artifacts from the data bus, slow edges, and sometimes not full swing on the output.The interesting thing is that due to the fact that U166 is located on the back side of the ACQ board, I soldered a regular 2.54" 0.5m flat cable so that it should be convenient to connect the oscilloscope probes.After soldering the cable, the oscilloscope started working, the errors completely disappeared and I was able to calibrate all channelsThe ringing disappeared. I connected this with the fact that the cable is an unmatched load on the data line and because of this, the level of logical 0 was shifted slightly. Later I soldered this cable to other ICs for other measurements and when I returned it back, I already received LT other errors. Perhaps this is due to the heating and cooling of the U166 during soldering of the cable. One way or another, my U166 was degraded.I ordered the components, but it won't be fast. I'll post the results when I receive the new chip.

author: MarkL
author_rank: Unknown
timestamp: April 29, 2024, 02:13:53 am
content: I've been following your progress on this thread, but I can't really add much since I don't have this scope.However, I will point out that the Agilent 16533A and 16534A scope cards for their logic analyzer line (which I do have) uses the same Logic Trigger 1FJ9-0002 ASIC or 1821-4786 carrier board, and the same Time Base 1SE6-0056 ASIC. Other scopes from that era also use this chip set. I'm sure HPAK re-used this design as much as they could.I think you're right that the Logic Trigger carrier card replaced the ASIC at some point for unknown reasons. The 16533A/16534A cards also exhibit this change in their lineage as well. I have some of both types and the behavior and specifications are identical. However, I don't think the 1821-4786 carrier card is a complete drop-in for the 1FJ9-0002 ASIC because there are other changes in that area on the 16533A/16534A cards between the two versions.I'm just pointing this out since these cards might be a possible source for ASIC replacements, if you should determine you need one.I don't want to send you on a wild goose chase since you are working on a completely different device, but I can also say the scope cards have a history of bad resistors, either completely open or wrongly high value. I've had a couple of bad termination resistors, one of which was on a clock line which caused multiple errors during self-test.I've also bad resistors on the output setting pins of local voltage regulators that caused the wrong voltage to be output. In one instance, it was on a regulator used to supply ECL termination networks on the card, again causing multiple and seemingly unrelated self-tests to fail.

author: ARF
author_rank: Regular Contributor
timestamp: February 20, 2025, 06:48:35 pm
content: Nobody was interested in the topic, so I forgot to write about the result.Yes, the problem was with U166. I just replaced it with a new one, the digital exchange became completely beautiful with logical trigger chip and the problem was solved.In the last post I mentioned that I got another error. It turned out that while I was working with the board, the resistor on the bottom was broken. After replacing the resistor, the problem was solved.

author: wkb
author_rank: Super Contributor
timestamp: March 12, 2025, 08:47:24 am
content: Actually, I am very interested in the topicReason: I received an Agilent 54825A as a present. Exactly the same problems like you described. As received it passed selftest, no issues. Last cal was done in 2000, so I decided to run a self cal. "What can possibly go wrong?".Now it has nothing but trigger errors during selfMeanwhile it has a CF card to boot from, I did some preventive maintenance (I hate RIFA X/Y caps in SMPSU), cleaned the pogo-pins of the hybrid sockets etc.Now I need to figure out if the corrsponding ALS chip you replaced in your 845A can be found & replaced.

author: ARF
author_rank: Regular Contributor
timestamp: March 12, 2025, 11:58:26 am
content: If you have "Logic trigger memory test is failing" then it should be a digital problem, like in my case.

author: nctnico
author_rank: Super Contributor
timestamp: March 12, 2025, 05:19:20 pm
content: It is more likely a soldering issue than a broken chip. In my 54845A U166 nearly fell off because it wasn't soldered properly. It was barely hanging on by 1 pin.

author: ARF
author_rank: Regular Contributor
timestamp: March 12, 2025, 07:24:26 pm
content: No, the chip has degraded. The soldering was excellent. I think that your case is unique. Moreover, local strong heating or cooling can change the properties of the chip and this can help in diagnostics or, on the contrary, hide the problem.

author: wkb
author_rank: Super Contributor
timestamp: March 12, 2025, 09:54:55 pm
content: Maybe electromigration affecting the ALS273?

author: wkb
author_rank: Super Contributor
timestamp: March 12, 2025, 09:57:49 pm
content: This is what my 825A produces

author: ARF
author_rank: Regular Contributor
timestamp: March 12, 2025, 10:45:49 pm
content: You have some other problem, the digital interface to LT is fine. There's something wrong with your pattern trigger. Try reading the help file that was added in the thread here. It describes some of the problems and mentions the blocks and chips involved.