help needed to repair HP spectrum analyser - Page 1
Forum section: electronics / repair

author: kenramesh
author_rank: Contributor
timestamp: April 25, 2018, 06:16:17 am
content: Hello guys,i need help desperately to repair my HP 8594A spectrum analyser.Pls help me .Thanx u all.

author: mrf245
author_rank: Regular Contributor
timestamp: April 25, 2018, 09:20:52 am
content: what's wrong with that?

author: BravoV
author_rank: Super Contributor
timestamp: April 25, 2018, 09:22:18 am
content: Here the solution ->https://www.eevblog.com/forum/repair/repairs-of-hp-8594a/

author: kenramesh
author_rank: Contributor
timestamp: April 25, 2018, 11:36:39 am
content: hithe link u mentioned was my first postthanx for the reply

author: BravoV
author_rank: Super Contributor
timestamp: April 25, 2018, 11:44:10 am
content: Quote from: kenramesh on April 25, 2018, 11:36:39 amDO NOT make new duplicated threads for the same topic, you're SPAMMING the forum.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: April 25, 2018, 12:32:40 pm
content: The fact that removing the counter-cable is improving the speed suggests that something is wrong with that circuit.That something connected to the YIG is getting warm is normal. That thing requires quite a bit of current to generate the magnetig fields.

author: Bud
author_rank: Super Contributor
timestamp: April 25, 2018, 01:08:45 pm
content: Slow speed - did you try setting tracescan time and resolution bandwidth to faster and wider values? Sounds normal behaviour to me if they are set too tight.FREQ UNCAL also may be a operational error- look up in the manual when it is displayed.All in all do you know how to operate this SA in the first place?

author: Simon
author_rank: Unknown
timestamp: April 26, 2018, 06:34:49 am
content: You won't get any responses unless you post a sensible question to which the answer is not an entire book because it is so vague (the answer to "how does this processor work" is a 500-2000 page datasheet for example). You need to explain in as much detail what you need and if it is a repair exact symptoms and what you have done so far.

author: krish2487
author_rank: Frequent Contributor
timestamp: April 26, 2018, 08:03:03 am
content: Just step back for a moment and look at the issue.QuoteIf you were at the other end and someone asked you the same question and gave you precisely this information. Would you be able to help them?? or even understand what is it that they are trying to communicate about the perceived problem or the instrument itself??Help us help you.Please start explaining what is that you have done, what is the problem you are seeing, what have to done to identify the issue behind and where is it that you have hit a road block? - in crisp, concise, complete statements.People are very helpful here. Any motivation to help you will vanish quickly if you are perceived to be another spammer or a person who is out to waste their time.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 08:36:37 am
content: Quote from: mrf245 on April 25, 2018, 09:20:52 am1.As the instrument is switched on , FREQ UNCAL is displayed which is a permanent fixture.2.When i try to calibrate using CAL OUT the result is SIGNAL NOT FOUND & SRQ110.3. The trace line is slow in movement , data entry response also appears to be slow.I couldn,t find service manual for 8594 series , but tried using 8590 series one.As per that manual either A7 analog pcb, A16 processor , counter lock , or YTO may be faulty but not able to zero-on by using this manual.I observed the following:1.on A7 analog interface board Q1 is getting warmbut if cable running to YTO removed from the PCB, heat is normal.2. FREQ UNCAL disappears & trace line moves fast when Counterlock board flat cable is removed

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 08:43:58 am
content: Quote from: SaabFAN on April 25, 2018, 12:32:40 pmu r right. In fact service manual is not available for this modelto come to a conclusion.I tried to find fault using 8590 series manual. As per the manual either A7 analoginterface or processor A16 or Counterlock A25 ( if option available )to be suspected.Not able to find troubles hooting chart for A7/A16/A25 boards. Schematics for the same r not available.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 08:45:07 am
content: Quote from: Bud on April 25, 2018, 01:08:45 pmI checked all the settings of the SA, all are normal .Iam using HP 8590L spectrum analyser (BW=1.8GHz) whereas 8594A is 2.9GHz.FREQ UNCAL is always present on the screen from power-on to power-off of the unit.As i mentioned earlier if i try calibrating the unit using CAL OUT , immediate result is SIGNAL NOT FOUND along with SRQ110 error.preset the instrument the same display FREQ UNCAL. When i remove the flatcable of Counterloack board the FREQ UNCAL disappears ( either the board is faulty or circuit is incomplete due to its removal )yes i know how to operate SA , Iam using HP 8590L, HP 8593E (BW=22GHz), front keys operation of all the 3 SA's are same.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 08:48:00 am
content: Quote from: BravoV on April 25, 2018, 11:44:10 amthis topic :https://www.eevblog.com/forum/repair/repairs-of-hp-8594awas made on April 17, 2018 but since I got no response,i made this one again .

author: krish2487
author_rank: Frequent Contributor
timestamp: April 26, 2018, 08:54:03 am
content: Exactly what BravoV was trying to gently inform you. When there is no response to a thread, the forum etiquette is to "bump" the same thread or update the status or your efforts or information. Not to create a new thread.PS: Same with the responses, it is much much easier if you responded to all the points in one reply instead of staggering each quote and rebuttal answer in a separate post.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 08:57:37 am
content: Quote from: krish2487 on April 26, 2018, 08:03:03 amThe above quote u mentioned was one my reply to Bud, actually this is thestart of my explanation :1.As the instrument is switched on , FREQ UNCAL is displayed which is a permanent fixture.2.When i try to calibrate using CAL OUT the result is SIGNAL NOT FOUND & SRQ110.3. The trace line is slow in movement , data entry response also appears to be slow.I couldn,t find service manual for 8594 series , but tried using 8590 series one.As per that manual either A7 analog pcb, A16 processor , counter lock , or YTO may be faulty but not able to zero-on by using this manual.I observed the following:1.on A7 analog interface board Q1 is getting warmbut if cable running to YTO removed from the PCB, heat is normal.2. FREQ UNCAL disappears & trace line moves fast when Counterlock board flat cable is removed

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 09:01:51 am
content: Quote from: krish2487 on April 26, 2018, 08:54:03 amthanx krish , but as Iam new to this forum joined on April 16 , 2018 , I need guidance from All of You both related to forum & technical aspects.

author: krish2487
author_rank: Frequent Contributor
timestamp: April 26, 2018, 09:07:17 am
content: Let me put that in a more clear way.Pictures - of the schematics in the service manual of the specific section, of the instrument you have, Teardown pics if needed, screen captures of the instrument while in operation.If the service manual of your specific model was not available then why did you choose what you are using now for repair?What was your troubleshooting mindset?? Why did you do and observe what you did?What did you do in isolating the problem ? Where did you go from there?? Did you try tracing the signal path on the boards you mentioned??Did you check all the voltages and waveforms on the test points?? Power supply voltages??Why did you feel the need to check the temperature of "Q1" what is the bearing of that component on what you suspect is the fault?? Is it a part of the signal path??If you do not explain your methodology in detail other than vague questions, others cannot help you!!I hope you understand what you have to do to receive help?This is not a free service help forum. And people most certainly cannot read your mind. If you are not absolutely clear in what help exactly you want, you will not receive much!TLDR; If you expect to be spoon fed with the solution to your problem with the equipment then spoon feed us here with all the details. Even If you deem them to be irrelevant.

author: BravoV
author_rank: Super Contributor
timestamp: April 26, 2018, 09:24:18 am
content: Quote from: kenramesh on April 26, 2018, 09:01:51 amNo excuse being new, its called consideration, manner and diligent especially you're asking for help, its universal language everywhere in the world.Just see your request below ..Quote from: kenramesh on April 25, 2018, 06:16:17 amImagine in India, two persons that you never know in your life, approach you ...1st person ask .."I need help desperately to repair my bicycle, Pls help me ...."... thats it, he said nothing else2nd one ask exactly this ...I need help desperately to repair my bicycle, Pls help me .... it has flat tyre and I don't know what next ..."... even this sounds abit weird as you just need to say or ask for help for an air pump to inflate, but still the 2nd one is way better than the 1st one that is so lazy even asking for help.Now back to your 1st post, what are you expecting people to respond with that kind of lazy request asking for help ? And worst, you claimed your self know and familiar how to operate it.I almost responded you with sarcasm like this ..."Have you push the power button ?" or .."Please make sure you've plug into the mains socket" ....... cause you deserved with that kind of harassment.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 10:01:59 am
content: The below mentioned stuff was my first request on this forum on April 17, 2018 with 172 views , 0 replieshttps://www.eevblog.com/forum/repair/repairs-of-hp-8594awhich is now (today) locked due to duplicate thread.Everyday I used to edit my post to bring it on top becoz no replies were received & the topic was fading from page 1. I tried for 3 days , then made one more post ( present post )''Online kenrameshContributorPosts: 9Country: inView Profile Personal Message (Online)repairs of HP 8594A spectrum analyser« on: April 17, 2018, 07:13:49 pm »Removehello all ,I have been facing problem with HP 8594A spectrum analyser.1.As the instrument is switched on , FREQ UNCAL is displayed which is a permanent fixture.2.When i try to calibrate using CAL OUT the result is SIGNAL NOT FOUND & SRQ110.3. The trace line is slow in movement , data entry response also appears to be slow.I couldn,t find service manual for 8594 series , but tried using 8590 series one.As per that manual either A7 analog pcb, A16 processor , counter lock , or YTO may be faulty but not able to zero-on by using this manual.I observed the following:1.on A7 analog interface board Q1 is getting warmbut if cable running to YTO removed from the PCB, heat is normal.2. FREQ UNCAL disappears & trace line moves fast when Counterlock board flat cable is removedwaiting for ur help Pls suggest how do proceed.Thanx in advanceLocked due to duplicate thread:https://www.eevblog.com/forum/repair/help-needed-to-repair-hp-spectrum-analyser/msg1494742/#msg1494742« Last Edit: Today at 04:19:33 pm by gnif » "I did mention in detail the problems I was facing in my first thread . I was considerate , but dint receive any reply.In my new thread , even if my opening post was short , as soon I received reply I mentioned all the problems I was facing with the SA.Iam not complaining or blaming but as you mentioned consideration , manner , deligence , I thought of mentioning it to u.

author: kenramesh
author_rank: Contributor
timestamp: April 26, 2018, 10:22:15 am
content: Quote from: krish2487 on April 26, 2018, 09:07:17 am(1) I checked power supply voltages , all are fine : +12v , +/- 15v, +5 V ( on processor board testpoints).(2) We use this SA , the unit failed so trying to repair. We have one more SA HP 8590L which is 1.8GHz BW. We need 2.9 GHz.(3)Service manual available is HP 8590 series with differs with HP 8594A but basic the same.As per the manual if FREQ UNCAL occurs either A7/A16/A15/A8 /A25(if board present in the unit ) might be faulty.A7--Analog onterfaceA16--ProcessorA15--MotherboardA8--PowersupplyA25--counterlockas we dont have any spare boards to zero-on the problem I am trying to get help from here.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: April 27, 2018, 12:11:45 am
content: You have run the internal self-test?Just a shot in the dark: Was the SRAM-Battery / The Chip with the Calibration-Data ever changed? If the instrument loses these information, it may very well be that the coarse DAC for the YTO is putting out the wrong values so the PLL cannot lock anymore.

author: hendorog
author_rank: Super Contributor
timestamp: April 29, 2018, 03:26:29 am
content: Quote from: SaabFAN on April 25, 2018, 12:32:40 pmYIG's normally have a heater.Here is some info on driving one from a power supply, although not much use unless you have another way of measuring the output.http://www.rollanet.org/~joeh/projects/Connecting_the_HP_5086-7023_YTO.pdf

author: kenramesh
author_rank: Contributor
timestamp: April 30, 2018, 07:32:59 am
content: Quote from: SaabFAN on April 27, 2018, 12:11:45 amIam gonna check the same & get backthank you

author: kenramesh
author_rank: Contributor
timestamp: April 30, 2018, 07:34:23 am
content: Quote from: hendorog on April 29, 2018, 03:26:29 amgoing thru the info providedthank you

author: HighPrecision
author_rank: Unknown
timestamp: April 30, 2018, 11:19:16 am
content: I have two preliminar service manuals for 8594A and 8595A, both are referenced to 8593A service manual as similar.8594A:https://www.dropbox.com/s/tcbbsknii8df9n3/8594A_Preliminary%20Service%20Manual.pdf?dl=08595A:https://www.dropbox.com/s/e3gdwtknw44ndej/8595A_Preliminary%20Service%20Manual.pdf?dl=0I'm unable to find a manual for 8593A, but found a complete manual for 8595A:http://www.ko4bb.com/getsimple/index.php?id=download&file=HP_Agilent/HP_8595A_Service_Manual.pdfPage 421 describes possible SW/HW causes of "FREQ UNCAL" message.Starting here you find CLIP schematics:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_8590_Spectrum_Analyzer/HP_8590_Clip

author: kenramesh
author_rank: Contributor
timestamp: April 30, 2018, 11:48:22 am
content: Quote from: HighPrecision on April 30, 2018, 11:19:16 amI ll go through the manual links u provided & get back to uthanks a lot

author: kenramesh
author_rank: Contributor
timestamp: May 09, 2018, 09:32:44 am
content: Quote from: SaabFAN on April 27, 2018, 12:11:45 amInternal self test ? Tried calibration , adjustments, diag , troubleshooting related tests bu t dint come across internal self tests in instrument menu or in the manual.Checked the battery its fine , I even tried replacing a new battery .

author: kenramesh
author_rank: Contributor
timestamp: May 09, 2018, 09:38:44 am
content: Quote from: hendorog on April 29, 2018, 03:26:29 amI tried but couldn't perform this task.thankyou

author: kenramesh
author_rank: Contributor
timestamp: May 09, 2018, 09:42:01 am
content: Quote from: HighPrecision on April 30, 2018, 11:19:16 amRead the manuals .Helpful schematics .As spare parts not available got stuck .Analog Interface, YTO, Counterlock one of the part might be the culprit.Thank you for the info provided.

author: kenramesh
author_rank: Contributor
timestamp: May 09, 2018, 09:52:17 am
content: I measured 10 pin connector on YTO (5086-7833) oscillator with digitalmultimeter after the analyser was switched -on.pin nos. standardsignal obtainedPin1 = minus 15v = minus 15.02vpin2 = a gnd = -pin3 = a gnd = -pin4 = +5v = +5vpin5 = maincoil+ = +14.81vpin6 = maincoil- = +9.63vpin7 = a gnd = -pin8 = +15v = +14.83vpin9 = FM-signal = 0.041vpin10 = FM+signal = 0.041vAre these obtained values at pin 5,6, 9, 10 right or wrong.

author: GrifTech
author_rank: Newbie
timestamp: March 01, 2019, 07:07:03 pm
content: Hi! Had the same issue, it's most likely the yid ocillator. Measure its output. Should be between 15, and 20dB.Hope you have fixed the issue.

author: C.Mueller
author_rank: Newbie
timestamp: October 18, 2022, 10:56:13 am
content: ...well, because this sounds familiar I didn't start a new topic (sorry Kenramesh). I also have trouble with our company's HP8595A spectrum analyzerafter replacing the internal 3.7V battery (which was from 1991!)Yes, I know there is another guy with HP8595E but he has the luck that his analyzer still responds whilemine here shows these things after startup:FAIL: 0030 0000000000 FREQ UNCALI tried to do the internal calibration (lead to this):CAL Signal not found (I also tried an external signal generator set to 300MHz -20dBm)Last but not least I tried internal diagnosis(after a while the analyzer doesn't respond anymore to pushing buttons)Pushing the "Preset" button leads to a bootloop (restart also, I have to unsolder the battery and discharge the 0.22F capacitorin order to get the analyzer started).It seems that there are more bugs to fix.I don't have to repair it on my own, I'm absolutely happy if you could name me a capable service provider (in europe) who isspecialized in repairing (and calibrating) of old spectrum analyzers.Thanks

author: lugaw
author_rank: Regular Contributor
timestamp: May 09, 2023, 02:16:55 pm
content: Meanings of the SRQ message:SRQ 110 is Hardware Broken

author: Samukas
author_rank: Newbie
timestamp: January 25, 2024, 03:29:01 pm
content: Hello, my name is Samuel, I would like to know if it is possible to send the firmware for the HP 8594A spectrum analyzer, I can't find it anywhere, thank you to anyone who can help. It could be any revision from the year 92.