hybridfree/eevblog-posts huggingface dataset:
Kenwood DP-1000 no laser movement, the cog is clicking - Page 1
Forum section: electronics / repair

author: pjasio253
author_rank: Newbie
timestamp: March 22, 2024, 07:54:37 pm
content: Hello,After inserting the disc, there is no full TOC reading, but the laser is set to track no. 1 and plays it for up to approx. 20 seconds. An attempt to jump to subsequent tracks causes the laser to return to track no. 1 anyway. During such attempts to "pull" the reading, a quiet knocking noise under the mechanism can still be heard. I managed to observe it and it looks like the circular gear from the laser feed motor encounters "some" resistance and jumps off the teeth of the plastic guide. If I move the gear wheel away for a moment, the laser itself moves along the metal arms of the mechanism without any resistance. I am sending a link to the video, although it is not my own, but it shows the view of the gear wheel and the guide on which this effect occurs.I would be grateful for any tips.

author: m k
author_rank: Super Contributor
timestamp: March 29, 2024, 02:14:33 pm
content: So a mechanical issue of some sort.Maybe it's just worn out.Are parts moving also around their supports, like in the video?If there is a block you should feel it when moving parts manually.But it can also be present only when angles are a bit off, like in video.

author: temperance
author_rank: Super Contributor
timestamp: March 29, 2024, 04:05:59 pm
content: From the video it is clear that the whole mechanism is bending when the thing starts.

author: amyk
author_rank: Super Contributor
timestamp: March 30, 2024, 01:49:24 am
content: Definitely a mechanical problem. The sled should move by gravity if the motor is removed. Might need some lube at the right places.

author: David_AVD
author_rank: Super Contributor
timestamp: March 30, 2024, 02:41:48 am
content: Carefully inspect all of the gears for damage. I've seen a few Kenwood audio products in recent years where the plastic gears are crumbling.

author: floobydust
author_rank: Super Contributor
timestamp: March 30, 2024, 03:30:47 am
content: Last time I had the click click click with a CD transport, it was the slide seizing up, it needed lube. Or maybe the worm shaft I forgot.You can hold the drive gear away and see how it slides, if it binds.
kenwood dsc-8200 dso bios battery - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: May 28, 2020, 02:01:42 pm
content: Hi all my new scope has arrived,it displays "low bat",i assume it has like a bios battery thats u/s,has anyone any idea where to find it?,ive looked but cant see it,it looks like it has to be totaly taken apart to locate it,has anyone ever swapped one of these?,cheers m3vuv.

author: sorenkir
author_rank: Regular Contributor
timestamp: May 28, 2020, 07:13:16 pm
content: Hi,Did you try to Google-translate this page, which seems to deal with backup battery ?https://w.atwiki.jp/ryofox/pages/141.htmlMichel.
Kenwood HB890 (k Mix) power cable replacement - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: March 21, 2023, 01:00:10 pm
content: I have one of these and the insulation on the flex is starting to crack...It should be easy to fix if only I could get inside the darn thing!!! There's no obvious route to open it up!Thanks in advance for any guidanceD.

author: perdrix
author_rank: Frequent Contributor
timestamp: March 21, 2023, 01:43:47 pm
content: Excellent, thank you so much!D.
Kenwood HM-332 micro hifi repair  - Page 1
Forum section: electronics / repair

author: psfm
author_rank: Contributor
timestamp: September 28, 2020, 11:20:29 am
content: Hello,I'm trying to repair a Kenwood micro hifi system, but I'm facing some issues.EDIT: I forgot to write that the I am trying to repair the system, because I would turn it on and after a few seconds it would shut down by itself.In order to isolate the problem, and since everything's ok with the board marked with the green square, I'm powering the transformer, marked with the red square, directly. (pict1)What happens, and I can't understand the circumstances, sometimes instead of reading the values marked with the red circles, I get 0V and the point next to D8 is shorted to Ground. (pict2)What could be the issue?Thank you.Kind regards,Marco

author: psfm
author_rank: Contributor
timestamp: September 28, 2020, 03:58:57 pm
content: From caps C51 and C52 (out of the circuit) I'm getting 2000uF instead of 2200uF. Could they be causing the problem?Kind regards,Marco

author: hubee
author_rank: Newbie
timestamp: February 18, 2022, 11:27:46 am
content: Hello Marco. Have you find anything? I have exactly the same pb? I haven't looked for the cause yet and I thought that if you had found something I would save time!

author: decoder_82
author_rank: Regular Contributor
timestamp: February 18, 2022, 11:31:13 am
content: Quote from: psfm on September 28, 2020, 03:58:57 pmDid you check the ESR value of the caps ? Maybe this could help to confirm if they are bad.
Kenwood interboard coax connectors - Page 1
Forum section: electronics / repair

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: October 25, 2020, 12:36:59 pm
content: Kenwood especially, but other manufactures use this small RF connector, coax male end looks like a little arrow pushes on to female connector on a board. Used for board to board RF connection with short small diameter coax.Kenwood TS 50 part number is E 04 0154 for the receptacle (female), but looking that up is no helpI have been trying to find out what the proper designation for this connector is with no success. I even have a crimp tool for it.Can anyone tell me what these connectors are called?? Maybe who carries them?Thanks, Wally

author: vk6zgo
author_rank: Super Contributor
timestamp: October 25, 2020, 03:13:58 pm
content: Quote from: Wallace Gasiewicz on October 25, 2020, 12:36:59 pmIcom used them, too (in the IC575a), & Midland in their low band VHF stuff from the 1980s.

author: bob91343
author_rank: Super Contributor
timestamp: October 25, 2020, 08:18:26 pm
content: TMP / Taiko Denki

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: October 25, 2020, 09:35:05 pm
content: Thank you very much.TMP Connectors Taiko DenkiJust so everyone else can see what we are talking about:
kenwood kfr-5080D - Page 1
Forum section: electronics / repair

author: mrrcomp
author_rank: Contributor
timestamp: October 15, 2023, 07:38:25 am
content: HII have this kenwood kfr-5080D and i am looking for a replacement volume knob. The volume control works fine with the remote but it doesnt have a know and seems the stem of it is borken?? From the schematic i see its a "rotary encoder" but no other info seems to be listed for it.Any suggestions how/where i can purchase one to switch it out with ?RegardsMeir

author: coromonadalix
author_rank: Super Contributor
timestamp: October 15, 2023, 02:42:24 pm
content: i think you meant KFRV-5080Dhttps://www.audioservicemanuals.com/k/kenwood/kenwood-krfv/159708-kenwood-krfv-5080-d-service-manualit seems to be a standard encoderpart no T99-0664-05 location S815 on the front pcb

author: mrrcomp
author_rank: Contributor
timestamp: October 16, 2023, 03:45:38 am
content: oops typo yesso when u say a "standard" encoder?? Can you suggest an actual part number?RegardsMrrcomp
Kenwood KR-9400 No Stereo light in FM, no audio with FM mute on. - Page 1
Forum section: electronics / repair

author: SAS73
author_rank: Contributor
timestamp: November 06, 2023, 01:11:43 pm
content: Dear friends,I am trying to troubleshoot an Kenwood KR-9400 , low beacon voltage ( 0.78 VDC) Tested Qb7 and Qb8 seem OK. tried to adjust Lb5 , little more voltage after adjustment but not by much .General question : What is exactly beacon signal does ? Is it just for a stereo light indicator, and FM mute circuitry ?Thanks!

author: darkspr1te
author_rank: Frequent Contributor
timestamp: November 06, 2023, 02:04:03 pm
content: On my old Kenwoods FM muting would mute NONE FM transmitted stations, so if you get no audio even on FM tranmissions with it on then its possible theres a issue the fm decode or seperationlook at board x04-104010 coming from FM IF board , it shows the stereo signal system. Also later on in the manual is shows the voltage readings for setting most of the VR'sthis is from the manual found athttps://elektrotanya.com/kenwood_kr-9400-service-manual.pdf/download.html#dldarkspr1te

author: SAS73
author_rank: Contributor
timestamp: November 07, 2023, 12:38:27 am
content: Thanks for reply !I have a very good FM RF signal from antenna ( I had also tried signal generator) but if I press FM mute, no audio, probably because i don't have a 5 volts on TP5 terminal ( beacon), I had injected 5VDC to that terminal and FM mute works, the question is why I don't have 5 volts on that terminal?I had tested all transistors and diodes on IF board. All tested good.

author: darkspr1te
author_rank: Frequent Contributor
timestamp: November 12, 2023, 02:37:28 pm
content: Did you download and read the service manual I posted?, i has a trouble shooting section that gives a flow chart of failure and what to check.darkspr1te

author: SAS73
author_rank: Contributor
timestamp: November 14, 2023, 02:10:16 am
content: Yes, I downloaded SM, replaced HA1156 , realigned according service manual , receiving in Stereo now, FM mute works also , THANKS
Kenwood TS-430S problem - Page 1
Forum section: electronics / repair

author: N2TCG
author_rank: Newbie
timestamp: June 17, 2024, 03:34:12 pm
content: I bought a Kenwood TS-430S, it has one problem. When powering up the display is totally blank and no receive. If i reset the cpu by holding in the A=B button and then power unit on and release A=B button, the radio works fine. I have to do this every time i want to use radio. Has anyone had this problem and if so what is solution? Thanks N2TCG

author: coromonadalix
author_rank: Super Contributor
timestamp: June 17, 2024, 05:30:06 pm
content: better chances onE-HAMhttps://groups.io/g/ts430/topic/ts_430s_starting_on_a/75079740https://www.vintage-radio.net/forum/showthread.php?t=210920https://www.reddit.com/r/amateurradio/comments/e7dq5/my_kenwood_ts430s_died_today_then_i_found_this/

author: Andy Watson
author_rank: Super Contributor
timestamp: June 17, 2024, 05:36:36 pm
content: Quote from: N2TCG on June 17, 2024, 03:34:12 pmWhich suggests the processor and associated hardware is fine but something is stopping it from completing its initialisation. Going for the low-hanging fruit first - does it need a new battery?

author: CaptDon
author_rank: Super Contributor
timestamp: June 17, 2024, 08:53:00 pm
content: Does kind of sound like the non-volatile memory battery is dead. I am far more familiar with the 440 model who's biggest problem is PLL unlock due to aging plyobond glue in the PLL section. I think 430's may have the same problem.
Kenwood TS-450S Low Audio problem - Page 1
Forum section: electronics / repair

author: K9MBQ
author_rank: Newbie
timestamp: April 25, 2019, 05:48:59 pm
content: Have a TS-450S Transceiver from an SK Ham Estate that seems to work all OK, puts our rated power, but Audio on spkr is very weak (Checked spkr - OK), a little better on phones but there is definitely a problem. Any members experienced a similar issue and can provide thoughts on a Fix?Thanks - Alan K9MBQalan.swinger@gmail.com

author: Rollin Hand
author_rank: Regular Contributor
timestamp: April 27, 2019, 12:13:06 pm
content: did you check the ceramic filters?

author: K9MBQ
author_rank: Newbie
timestamp: April 28, 2019, 03:55:43 pm
content: Thanks, but not sure I know enough to ID them and/or check them. Can you point me ?\- Alan K9MBQ

author: K9MBQ
author_rank: Newbie
timestamp: April 29, 2019, 11:23:43 am
content: Rollin - How would I do what you suggest? - Alan K9MBQ

author: mrf245
author_rank: Regular Contributor
timestamp: April 30, 2019, 04:27:08 am
content: Check electrolytic capacitor beside audio amplifier, maybe 470uF/25V, if it leak, replace and clear PCB nearby carefully, replace 2 black 455KHZ filters if needed.

author: K9MBQ
author_rank: Newbie
timestamp: May 01, 2019, 11:24:56 am
content: Tks. - Alan

author: tkamiya
author_rank: Super Contributor
timestamp: May 01, 2019, 12:09:39 pm
content: I have repaired plenty of ham rigs. Most of them suffered low audio output. I found many of them had issue with its attenuation switch. Since there is so low level voltage present, oxide layer forms and basically disconnects the antenna. On SSB mode, it appears as if audio is low. This is so common that it is my first thing to check. Ditto for TX/RX relay, too.Fix is to use Deoxit D5 spray and "work" the switch few dozen times.I have yet to find any that had electrolytic issues, except in power supply circuit. This will usually result in work/no_work type issue. Or magic smoke emanating from inside. Unlike seemingly common practice, I do not automatically replace all caps.

author: K9MBQ
author_rank: Newbie
timestamp: May 09, 2019, 07:28:04 pm
content: Thanks to all for the advice. The problem was the 470 mfd 10V cap next to the audio Amp. Replaced it and audio is normal.73,Alan K9MBQ
Kenwood VR615 6 ch receivers No Display anyone repaired this? - Page 1
Forum section: electronics / repair

author: slbender
author_rank: Regular Contributor
timestamp: May 06, 2022, 09:31:08 am
content: I have two older Kenwood VR-615’s, 6 channel Surround Sound AM/FM Receivers, both have dead or NF panel displays, one shows standby red led and draws no power, the other when ON draws about 45 Watts, as per my Sencore PR-570.Readings on both sets - no obvious shorts to ground on any of the six amp channels at speaker terminals, between hot and ground, on Fluke meter set to either diode test, ohms, or low ohms ranges (40 ohm range). Main 8A fuse was replaced in one set.Any other hidden fuses in there? Any known failure modes that kills the power to the panel display?The SM covers eleven variations of the same set and is very, very confusing.Neither unit shows anything on the many digits and DTS, Dolby Digital, Pro Logic indicators panel display.Any threads or prior discussions - it’s a 2002 set using 3 channel STK413-020A hybrid’s for 6 x 100 wpc.-Steven

author: m k
author_rank: Super Contributor
timestamp: May 18, 2022, 03:12:08 pm
content: The display seems to be pretty straight forward but AC powered.Same powering connector is providing -30V for driver chip and AC something enable signal for IC806 but it is said to be absent in VR615.Are you seeing those voltages?

author: strawberry
author_rank: Super Contributor
timestamp: May 18, 2022, 04:53:15 pm
content: standby check : Vstb 5.3V, F.OFF1, standby key 0/4.8Voperational : +/-12V ,-30V ,FL(filament) ,PROT1 ,PROT2
Kepco BOP36-5M is a bipolar power amp. - overload alarm below nominal voltage - Page 1
Forum section: electronics / repair

author: golashki
author_rank: Newbie
timestamp: January 01, 2023, 07:41:44 pm
content: Kepco BOP36-5M is a bipolar power amplifier with a voltage range of approx. +/-36V and +/-5A. It can be powered from the internal reference voltage, which enables operation as a four-quadrant DC power supply or working as an external signal amplifier. Very solidly built and interesting device.My item has some problems with controlling the full 36V voltage(+36V/-36V). The overload alarm is triggered at approximately 18 volts. I measured the power transistors and they are all OK. The control boards also look OK (capacitor ESR, transistor, diodes, etc.). However, something is not as it should be. Without a schematic and instructions, I am unable to find the problem.This is an older model, probably one of the first amplifiers of this type produced by Kepco. Only service manuals of later models are available on the Internet, those with both voltage and current control. I really searched all the links from eevblog (by the way, collecting over a dozen service manuals for other KEPCO power supply models).I know that I can buy a print version on eBay, but the cost of shipping to Europe exceeds the cost of the service manual ...Does anyone on the forum have an electronic version of the service manual exactly for this model: Kepco BOP36-5M?Or at least for models: 36-1.5M, 72-1.5M, 72-5M?

author: precaud
author_rank: Frequent Contributor
timestamp: January 02, 2023, 02:39:18 pm
content: I found the main problem with that whole Kepco series to be interconnection issues. Everything, including the output devices, is on plug-in connectors, whose fingers look robust but contact deteriorates with time. A thorough cleaning of all of them is pretty much required to have any confidence.

author: alm
author_rank: Super Contributor
timestamp: January 14, 2023, 06:36:45 pm
content: Have you tried emailing Kepco? In 2016 I sent them an email (hq@) for a BOP 100W unit with voltage and current control, and a nice employee promptly responded with a PDF manual with full schematics. The manuals were available on their website, but without schematics. The one they emailed included schematics.

author: Scrapcollector
author_rank: Newbie
timestamp: July 18, 2023, 12:52:47 am
content: Does anyone have a transistor comparison / replacement recommendation or just some basic data for these old devices? 119-0113 or the 0119-0128 in a 72-5m.Are these general purpose low gain 100...150W transistors or darlingtons?I mailed the company but no success so far.
Kevex microfocus tube missing serial commands - Page 1
Forum section: electronics / repair

author: IgorIgor1233123
author_rank: Newbie
timestamp: April 29, 2019, 06:00:21 pm
content: Hi,i have a microfocus X ray tube from Kevex. but it is controlled over RS232.my Problem is that im missing a crucial Serial command for the Tube conditioning.The rest of the commands are documented over the RS232 Interface.But without running this command it will not work.no worries i know what im doing, I know how to work with radiation.Hope this is in the correct section of the Forum

author: IgorIgor1233123
author_rank: Newbie
timestamp: May 09, 2019, 12:32:17 pm
content: no one?

author: IgorIgor1233123
author_rank: Newbie
timestamp: March 10, 2020, 10:00:03 am
content: push

author: JKKDev
author_rank: Regular Contributor
timestamp: March 10, 2020, 11:02:09 am
content: Any chance you could figure out some sort of structure of the commands and try brute forcing? Maybe dump the rom and look for commands in there? Do you know someone that's running a kevex product where you could listen to the serial connection and find out what the command is? Did you try contacting the company about software or what they call Product Interface Specification (Kevex p/n 5973-3036). Just listing some things that might or might not be usable in this case...

author: stdlogicvector
author_rank: Newbie
timestamp: August 06, 2021, 03:20:56 pm
content: I've got a similar tube and found this manual by searching for "Error 28 Tube Conditioning" :https://www.spellmanhv.com/-/media/en/Technical-Resources/Manuals/uXRB130P65MAN.pdfIt contains all the commands that are not listed by the HELP command, including the tube conditioning program.Hope this helps!

author: IgorIgor1233123
author_rank: Newbie
timestamp: August 15, 2021, 12:34:52 pm
content: Yes I found that as well, forgot I had this post here sorry only saw it now, have fun and keep it safe hope you have still some operating time left
Kevin igbt-1450va - Page 1
Forum section: electronics / repair

author: sarry86
author_rank: Contributor
timestamp: April 28, 2023, 07:19:12 am
content: Hello everyone, I am a newbie here but I would like to request if someone has access to this inverter/ups schematic diagram, help me with that. It's Kevin IGBT 1450 VA

author: sarry86
author_rank: Contributor
timestamp: April 28, 2023, 07:29:03 am
content: This is the internal circuit board

author: sarry86
author_rank: Contributor
timestamp: April 30, 2023, 11:23:40 am
content: Somebody please help me

author: coromonadalix
author_rank: Super Contributor
timestamp: April 30, 2023, 01:42:02 pm
content: BE patient if you are pushy in a way it will deter people to help you, if someone can help, you may receive help or not if its not possible
Key Fob IC identification help - Page 1
Forum section: electronics / repair

author: gkmaia
author_rank: Frequent Contributor
timestamp: November 12, 2020, 07:31:55 am
content: I got a key fob that is faulty.From what I can see the there is a crystal and a Philips RF ID transmitter.From what I could find it has an SSOP20 eprom in it so I suspect that is where they store the programming and the code. The other IC is a SSOP16 and not sure that is for. Seems to be driving the crystal from pins 10 and 11.Then it gets myself confused as I from what I could learn the driving transmitter IC is usually connected to the the crystal and the other IC is where they store the code.Anyone with some experience on these things? My goal is basically to replace the transmitter hopping the other ic holds the code.

author: amyk
author_rank: Super Contributor
timestamp: November 13, 2020, 01:31:28 am
content: One is a PCF7321 (seems equivalent to PCF7921), the other one I can't read the markings on.

author: gkmaia
author_rank: Frequent Contributor
timestamp: November 14, 2020, 05:35:15 am
content: Seems to be but the pinoput does not matchI did a schematics of the PCB. I think the other IC is a Tda5001 frequency synthesizer.So bsed on that the ID code is defintevilly on the philips right?

author: gkmaia
author_rank: Frequent Contributor
timestamp: November 14, 2020, 11:52:05 am
content: schematic updates

author: fzabkar
author_rank: Super Contributor
timestamp: November 16, 2020, 11:17:21 am
content: Here is the datasheet for the PCF7x41 single-chip solution:PCF7x41ATJ, NXP, Security Transponder and RISC Controller (STARC 2XLite):https://media.digikey.com/pdf/Data%20Sheets/NXP%20PDFs/PCF7x41ATJ.pdfPage 10 talks about the EEPROM content at delivery.QuoteAISI, the PCF7x21 chips are the predecessors of the PCF7x41 and are part of a 2-chip solution.Page 4 of the same datasheet explains the part number coding.QuoteSo the "73" chips are ROM versions while "79" chips are E-ROM versions ("FLASH like features").

author: ijchan223
author_rank: Contributor
timestamp: November 22, 2020, 04:56:00 am
content: what does it go to, a fob from early 2000s should be easily programmed with a sequence and the key.
keypad 8563e usable for 8563e? - Page 1
Forum section: electronics / repair

author: pe2ben
author_rank: Contributor
timestamp: April 07, 2022, 09:34:46 pm
content: Hello everyoneMy keypad buttons from my hp8563A badly responds.On ebay i can find replacement keypads for a hp8563E but does this fit on a hp8563A?Regards Ben

author: djsb
author_rank: Super Contributor
timestamp: July 31, 2022, 05:52:15 am
content: You need to check if the part numbers are the same for both keypads. Also, your keypad may be able to be dismantled and cleaned (with a fingernail to clean the carbon on the buttons and some iso alcohol for the contacts on the PCB-I've just cleaned the keypad on my HP8563E). You need to do some research.
Keypad replacement - Page 1
Forum section: electronics / repair

author: PlainName
author_rank: Super Contributor
timestamp: October 28, 2024, 02:28:03 pm
content: Got a keypad (mentioned elsewhere) with domed buttons. An official replacement is both unobtanium and expensive, so I am looking at a DIY solution.What I have in mind is a flex PCB, which JLCPCB would do for next to nothing (unless I add a stiffener, and then it gets uncheap. But what about the buttons? Perhaps a tactile switch would suit, but there are so many it is hard to know what to look for or which might be appropriate.Any suggestions?

author: Koray
author_rank: Regular Contributor
timestamp: October 28, 2024, 02:52:10 pm
content: Your holiness,Replacement cross-shaped domed switches are available on aliexpress:https://www.aliexpress.com/item/1005004544751246.html:-)K.

author: PlainName
author_rank: Super Contributor
timestamp: October 28, 2024, 03:01:19 pm
content: Thanks, but the switches themselves are fine - it's the tracking that is borked. With a replacement tracking layer, I'm not sure those switches are the right solution (specifically, difficulty in mounting on a flex PCB).
Keysight 34461A will not boot, need repair source - Page 1
Forum section: electronics / repair

author: kkayser
author_rank: Contributor
timestamp: July 24, 2021, 10:37:51 pm
content: I have a 34461A ser my 53209787, that will not boot. Does anyone know of a place that will repair it. Keysight's repair cost is prohibitive ($900+)

author: voltsandjolts
author_rank: Unknown
timestamp: March 28, 2024, 05:17:18 pm
content: Quote from: kkayser on July 24, 2021, 10:37:51 pm

author: coromonadalix
author_rank: Super Contributor
timestamp: March 30, 2024, 06:33:33 am
content: you have some threads here about this meter 61 and or 65 modelsome has a psu part failure, some have boot / memory corruption ? and or the baddest is the spear mcu who died

author: kkayser
author_rank: Contributor
timestamp: March 30, 2024, 01:52:58 pm
content: Quote from: coromonadalix on March 30, 2024, 06:33:33 amThat is a different 34461A long since sold for parts.
Keysight 3000X 3000T 4000A MSOX4154A P-CLOCK and ADC failure intermittent - Page 1
Forum section: electronics / repair

author: EE-digger
author_rank: Frequent Contributor
timestamp: December 22, 2021, 11:18:07 pm
content: Never posted here before so I apologize for cross-posting in the Test Equipment forum.My MSOX4154A is throwing P-CLOCK or ADC failures intermittently. It's two years out of warranty so I'm hoping someone has faced this and found a solution. While in warranty, it threw these errors a few times and then silence for months so I left it alone. Stupid, I should have had it checked under warranty.Keysight actually acknowledges that the problem exists on the Infiniivision series, although uncommon. Their solutions are self test, reload firmware, send it back for repair. If there is a repair, it's a design problem and they know it. I can't afford to fix it at the moment.I'm raising the temperature of my lab by 10 degrees to match the summer/'fall and see if that helps.
Keysight 33500B (33521B) Screen Saver not working  - Page 1
Forum section: electronics / repair

author: JohnPi
author_rank: Regular Contributor
timestamp: December 22, 2019, 06:50:10 pm
content: I have a couple of annoyances with my 33251B -- the screen is rotated slightly from horizontal (others have noted the same issue). I tried to disassemble it and align the screen, but it doesn't seem possible to realign. Second, the fan is always on, and is quite loud -- I'd like to replace it, but I didn't want to disassemble so far -- I might just put an R in series with its power.When I reassembled it, it powered up with an error message -- turns out the clock got reset -- so I set that again and now no errors occur. However, the screen saver now doesn't kick in -- it is supposed to dim the display after 8 hours of inactivity.Any ideas on how to fix this ?

author: HighVoltage
author_rank: Super Contributor
timestamp: December 22, 2019, 08:48:51 pm
content: Some of the 33500B series generators have indeed a slightly slanted display.You can actually fix this by opening the front panel and adjust the PCB rotational position.You might have to remove some plastic material on a guide.I have added a 100 Ohm (1W) resistor to the fan in my Keysight generator and it works perfectly.No need to exchange the fan.I am not sure about the screen saver.
Keysight 34450A Help - Page 1
Forum section: electronics / repair

author: Louis_C
author_rank: Contributor
timestamp: May 02, 2024, 12:43:02 pm
content: Hello all. I'm looking for some help on a Keysight 34450A. All calibration tests pass except for 100mV AC @ 100kHz. It reads 94.837. The Low limit is 96.700 and the high is 103.3. I tried performing the internal calibration and entering the new corrected reading for this test point and the unit rejects it and fails. I flashed the firmware to the latest version available ( 01.03-01.02). I'm not sure what else to do here. Can anyone give me some advice as to what to look at next? Thanks!

author: Greybeard
author_rank: Frequent Contributor
timestamp: May 02, 2024, 07:39:45 pm
content: Are you sure your source voltage is correct?Have you checked with another DMM?

author: Louis_C
author_rank: Contributor
timestamp: May 02, 2024, 08:30:29 pm
content: I had the 34450A connected to our Fluke 5500A during the internal cal/adjustment procedure.

author: floobydust
author_rank: Super Contributor
timestamp: May 04, 2024, 03:40:43 am
content: Is the ACmV reading stable?What about different (lower) frequencies. What about linearity - how is it at 25, 50, 75mV; still -5.16% ?We don't have a service manual or schematic to troubleshoot the ACmV path, and it's a custom DMM IC. Right to repair nah.The relays are kinda cheap so try working them, I don't think they have a lot of palladium lol. But I think the cmos muxes are doing the range switching work. If it was grossly overloaded on ACmV the H/W could be damaged, that's why I suggest seeing if it's just a span problem or more.There are two firmware loads - CPU for the main and MCU for the DMM portion and not sure if any F/W update covers both processors.
Keysight 34461A ADC error - Page 1
Forum section: electronics / repair

author: Lobisomem
author_rank: Newbie
timestamp: February 16, 2023, 06:17:06 pm
content: Hi,I have the 34461A and recently it boot with an error icon on the top right corner of the display. I did a self test (quick and full) and got the following errors:+624 Self-test falied: Coarse ADC error+625 Self-test falied: ADC offset+626 Self-test falied: ADC noiseI sent these informations to the only keysight representative in my country (Brazil) to get a quotation to repair. They charge me something around 1,000 US dollars. I figure that they will not change some faulty ADC that cost something around 50 USD. They will change the entire board. And like a good third world country, when you import something (like the board of this DMM) the taxes are insane. Hence the price they charge me. Or they are just too greedy.So, can anyone point me to some schematic of this DMM? Or better yet, point me to the ADC or other component that I can replace to get this multimeter fixed?Thanks in advanced.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 16, 2023, 09:11:51 pm
content: There is a schematics for the 34410 around somewhere in the web. AFAIK the ADC should still be essentially the same.Compared to the older 34401 the ADC is a whole lot more complicated. AFAIR there are 2 extra auxilary ADC chips for the coarse and fine part and chances are the problem is around the coarse one. A point to check is the supplies (e.g. bad tantalums ? ). It is not just the ADC chip that can wrong - there are other related parts too.I can fully understand the KS would swap the whole board, unless it would be an error that comes up very frequent.
Keysight 34461A Fried SPEAR320-2 - Page 1
Forum section: electronics / repair

author: Fixed_Until_Broken
author_rank: Regular Contributor
timestamp: May 13, 2022, 01:00:03 am
content: They were throwing this thing out at work and so I scored it for the low price of jumping in the dumpster!I have an out-of-warrenty 34461A and the Spear320-2 is toasted on the front panel. If I get my hands on a blank SPEAR320-2 do I have any options for flashing it? I know you can flash these when they have a corrupted memory, but does the spear320-2 have any memory that needs to be flashed, or is it all on the NAND near it?Does anyone have experience with this repair and is willing to share some tips?

author: TheSteve
author_rank: Unknown
timestamp: May 13, 2022, 06:34:40 am
content: As far as I know if you can source a replacement processor and install it there is no programming needed.

author: Fixed_Until_Broken
author_rank: Regular Contributor
timestamp: May 13, 2022, 02:24:49 pm
content: Quote from: TheSteve on May 13, 2022, 06:34:40 amI just wasn't sure since the datasheet ofhttps://www.st.com/resource/en/datasheet/spear320s.pdfshows that it does have 32KB of internal memory so I wasn't sure if it is utilized at all or if it's all on the external memory.EDIT- Oh I see in Section 2.2 its factory a defined bootloader so I assume all spear320s-2 are the same.

author: autorepair78
author_rank: Newbie
timestamp: December 03, 2022, 04:38:01 pm
content: Is there anyone on the forum who had a problem with the processor in the 34XXX series and after replacing everything was back to normal? I am asking because I have the opportunity to buy a 34461A which, when turned on, only illuminates the LCD and nothing else works. When opened, you can see that the SPEAR320-S2 is very hot.

author: rolkinas
author_rank: Contributor
timestamp: December 11, 2022, 05:27:53 pm
content: Yes. Mine 34465A had same issue with boiling SPEAR320-S2 and white/black screen. Replaced it and problem solved

author: autorepair78
author_rank: Newbie
timestamp: December 11, 2022, 06:19:00 pm
content: Okay, thank you for info. How long did it work after a replacement processor? I am asking because I don’t know there is some problem with processors or maybe factory defect of matter?

author: rolkinas
author_rank: Contributor
timestamp: December 11, 2022, 09:33:12 pm
content: It was about half year ago. But meter is most of time switched off, so no many hour of work after repair.No programing was needed after replacement. Just switched on and worked.It is recommended to remove failed processor and check all supply voltages going to processor just in case. There are quite many of them

author: autorepair78
author_rank: Newbie
timestamp: December 12, 2022, 12:09:24 pm
content: Could you tell me where did you buy spear?

author: rolkinas
author_rank: Contributor
timestamp: December 19, 2022, 11:44:10 pm
content: Can't remember but it was mouser, farnell or digikey. Unfortunately neither of them currently have Spears in stock.
Keysight 34470A Front Panel PCB Repair - Page 1
Forum section: electronics / repair

author: alexm271175
author_rank: Newbie
timestamp: November 21, 2022, 12:19:26 pm
content: Hi,I have a 34470A. It does not boot when I turn the power on. I found in the service manual that in this case a frequency on the front panel PCB (TP200) should be testet. If it is not correct, change the front panel PCB for something about 350 euros...In my case there is no frequency on this test point. Before I will order a new PCB I would like to ask if maybe someone had the same problem and found the defective part?best regardsalex

author: HighVoltage
author_rank: Super Contributor
timestamp: November 21, 2022, 02:59:32 pm
content: Did you measure all DC rails for correct voltages and low ripple first?Just to make sure the front panel gets the correct supply?

author: Smith
author_rank: Frequent Contributor
timestamp: November 21, 2022, 04:59:16 pm
content: I had an 34465A which would not boot (similar build I guess). The front panel had a short on the lower 10uF multi layer caps, I think there where about 5 of them in parallel. One of them had shorted, in this case there was no fuse, so the transformer burned up. Replaced both and the unit is working again.You have to take out the front panel, they are placed near the connector to the main board if I remember correctly.
Keysight 34980A Slope Convergence DMM issue - Page 1
Forum section: electronics / repair

author: a100man
author_rank: Newbie
timestamp: June 28, 2023, 02:55:30 pm
content: Hi,I have a Keysight 34980A, and the self-test fails with only error 604 "Self-test: A/D slope convergence". In DMM mode, it reads 0.0V constantly, which I suspect is because the DMM is not reading at all due to the error. I know internally this DMM is similar to the 34970 and the 34401 and there has been some discussion on repairing those devices. Since the 604 is the only error I'm getting, I'm wondering if anyone has any ideas for a particular component I should check?Thanks

author: m k
author_rank: Super Contributor
timestamp: July 05, 2023, 02:44:19 pm
content: Hook a scope to A/D input and check if there is anything alive.
Keysight / Agilent MSO-X 3024A Repair - Page 1
Forum section: electronics / repair

author: cproo12
author_rank: Newbie
timestamp: July 13, 2023, 03:11:32 am
content: Hey there, I have a broken scope that I would like to fix.I am getting an error message: "The probe power supply has been shut down because an overload was detected. Remove at least one probe and press OK."I have no probes installed. I took the entire scope apart and checked the PCBA for damage but I didn't see anything obvious, bit of dust that I cleaned off but this did not resolve the problem.I'm not sure how it happened, but any advice would be great. I can press OK, but the message immediately pops up again preventing me from doing anything.Tried reaching out to Keysight and they quoted me $4,000... I am willing to pay money to repair but not that much! I don't even think the scope is worth that much money.

author: Shonky
author_rank: Frequent Contributor
timestamp: July 13, 2023, 04:14:56 am
content: Start with the basics? Voltage rails? Maybe if you can easily disconnect each channel's supply to figure out which is the faulty one. Presumably there's no info in a log as to which channel is affected?https://xdevs.com/doc/HP_Agilent_Keysight/Service%20Guide%20for%202000%203000%20X-Series%20Oscilloscopes%2075019-97084%20c20141015%20%5B150%5D.pdforhttps://www.keysight.com/au/en/assets/9921-02449/service-manuals/2000-3000-X-Series-service-guide.pdf?success=true

author: cproo12
author_rank: Newbie
timestamp: July 13, 2023, 04:51:18 am
content: Wow! I am so sorry! I have a copy of the service manual I downloaded from their website and my copy does not have that whole "Troubleshooting Internal Assemblies" section.Apologies again for not checking the links in the sticky more thoroughly and thank you for the linkI will post back with an update!

author: Shonky
author_rank: Frequent Contributor
timestamp: July 13, 2023, 05:01:26 am
content: Quote from: cproo12 on July 13, 2023, 04:51:18 amSeems to be a HPAK thing. Often the "current" official manuals have had information removed. For older gear sometimes they have full schematics that are simply removed in the newer versions (e.g. 34401A)
Keysight / Agilent MSO-X 7000A Repair - Page 1
Forum section: electronics / repair

author: smaultre
author_rank: Regular Contributor
timestamp: December 26, 2023, 10:20:11 am
content: Maybe somebody have any good service manual for it?It's boot and halt with message PLL unlock, uncalibrated..Do not response on any buttons.

author: smaultre
author_rank: Regular Contributor
timestamp: December 27, 2023, 02:10:08 am
content: I make some investigations.There is some measurements, 2 chips marked with RED getting really hot.Scopes boot to measurements screen with error message:"software failure,PLL unlock, uncalibrated, defaults loaded"Also it do not feed 5V to USB HOST connectors (can't read usb), butwhen i plug it to PC its find a new device..U1809 - oscillator powered, but tuned off state (worked, tested)U2901 74act04 Hex Inverter getting very hotU2520 act11374 Octal D-Type Edge-Triggered Flip-Flop getting very hot too500Mhz VCO generator module itself seems to startbut ACQ chips (5 pcs) do not start (no oscillations on pins some have log"1", some log"0")

author: HighVoltage
author_rank: Super Contributor
timestamp: December 27, 2023, 11:32:53 am
content: This is a MSO 7000A (No X)If you find a component to be hot and a supply voltage rail low, look for a short.Either an IC or a capacitor shorted is most likely the fault.Always start with checking all the voltage supply rails.Unfortunately there is no good service manual available.I have repaired a few of these 7000A and 7000B scopes and with enough time and effort, they are repairable,unless you get a fault in an agilent specific chip.

author: smaultre
author_rank: Regular Contributor
timestamp: December 27, 2023, 08:54:57 pm
content: Do you have any voltage measurements sheets? Can you test U1809 - oscillator, does it generating on the default state? Do you know how the VCO works here?

author: beyond
author_rank: Contributor
timestamp: December 13, 2024, 01:12:09 pm
content: Quote from: HighVoltage on December 27, 2023, 11:32:53 amHello, My DSO7014B cant not start user calibration, I checked the trigger output buffer (ACT11244) chip input pin and output pin, no signal, the input pin's routing can't be found after passing through the via, do you konw trigger output signal comes from which chip?I have described the problem in this thread（latest page)， could you please give some advice?https://www.eevblog.com/forum/testgear/agilent-mso-500060007000-anyone-hacked-these-scopes/700/
Keysight B2961A fails self test leaving channel disabled.  - Page 1
Forum section: electronics / repair

author: OnlyAdeline
author_rank: Newbie
timestamp: December 09, 2024, 11:36:46 pm
content: Hello all! Im brand new to the forum I hope this is okay for my first post.I have a Keysight B2961A low noise power source that is throwing a 141 self test skipped error on boot. It prompts to run the self test manually but it fails and gives two 131 errors. The attached pictures show the two 131 error descriptions in the log.I’m wondering if anyone has an idea of what I could do to try and clear the error, I’m considering taking the case off and trying to reseat any ribbon cables but I’m not sure if that makes sense for this error.I’ve contacted keysight support and they only offered to give me a quote for keysightcare. So before I go down that route I thought I would ask here and see if anyone had any ideas for me to try.Thanks for taking time to read my post!

author: Harry_22
author_rank: Frequent Contributor
timestamp: December 13, 2024, 10:07:24 pm
content: Hi!I would venture to suggest that the communication between the power source and the controller is broken. Usually communication goes through optocouplers which sometimes break.Is the source itself somehow controlled?Is it possible to set the output voltage?PSI don't want to give bad news, but it is possible that external voltage came and destroyed it.I have a similar source under repair now. Two channels out of four do not communicate with the central controller.

author: OnlyAdeline
author_rank: Newbie
timestamp: December 14, 2024, 11:36:18 pm
content: Hey! Thank you for your reply!That makes sense.It is just controlled by the front panel at the moment, it won’t let me set anything to do with output while that error is present.The source went into storage working a year or so ago and on first power up out of storage I got this error. So maybe some mechanical jostling loosened a connection or at least I’m hopeful that’s the case.If I decide to open it up I’ll share some pictures of its internals.
Keysight DAQ970A white screen - Page 1
Forum section: electronics / repair

author: hitecelec
author_rank: Regular Contributor
timestamp: August 09, 2025, 08:53:18 am
content: Hello AllWhite screen at power onAny cluesThanks in advanceRegardsAnand

author: voltsandjolts
author_rank: Unknown
timestamp: August 09, 2025, 09:27:53 am
content: A little more than zero information would be helpful here!Same front panel pcb as 344xx dmm series? Bad Spear? Bad NAND? Same debug port?https://www.eevblog.com/forum/testgear/keysight-34465a-reliability/https://www.eevblog.com/forum/testgear/keysight-34465a-reliability/msg5396783/#msg5396783https://www.eevblog.com/forum/testgear/keysight-34465a-reliability/msg5397311/#msg5397311https://www.eevblog.com/forum/repair/agilent-34461a-corrupted-flash/msg5880804/#msg5880804

author: hitecelec
author_rank: Regular Contributor
timestamp: August 09, 2025, 12:00:42 pm
content: HiWill investigate and revertThe power supplies seem okwhen i try to connect thru the USB instrument is not detected
Keysight DSO x2024a WON'T boot up. - Page 1
Forum section: electronics / repair

author: adot111
author_rank: Newbie
timestamp: March 02, 2025, 02:47:59 am
content: The oscilloscope X2024A is no longer working. Initially, it had a power supply issue. After checking a thread on the EEVblog forum (https://www.eevblog.com/forum/repair/dso-x-3024a-power-supply-defect/), I discovered that a capacitor and some other components were damaged. I replaced the faulty parts and measured the power supply output voltages: three pins provided 12 volts, and one pin provided 6 volts, which seemed normal.When I powered on the oscilloscope, it was able to turn on, but the power switch was unresponsive. As soon as I plugged it in, the scope would power up automatically. However, after turning it on and off about 3–4 times, it stopped working entirely. Now, it no longer performs a self-check, and only the 'Math' and 'Ref' indicators light up.https://youtu.be/o-EPREyD5PMhttps://photos.app.goo.gl/ACtNkkaVHom2FDmE8https://photos.app.goo.gl/fKZNn3JQo6NfGEnW7Do you guys have any suggestions? Thank you in advance.

author: adot111
author_rank: Newbie
timestamp: March 10, 2025, 06:00:22 pm
content: Can someone please help me to take a look at this issue? Is it NAND corruption issue?Thanks,

author: iAleks
author_rank: Regular Contributor
timestamp: March 10, 2025, 06:24:04 pm
content: Your scope trying turn on without press "Power button", its looks like you have other problem with AC/DC board or DC/DC board.Try look herehttps://www.eevblog.com/forum/repair/dso-x-2012a-power-supply-repair/
Fixed: Keysight (Agilent) E3640A linear PSU repair error 609 (ADC error) - Page 1
Forum section: electronics / repair

author: coy
author_rank: Contributor
timestamp: May 11, 2023, 10:14:14 pm
content: Hi,I got a Keysight E3640A linear PSU for repair. It boots up successfully and all keys menus etc. are working. But output is disabled and it states it detected error 609.Apparently it is a newer build, not the early Agilent labeled version from 2000s. My PSU has a serial number of MY56xxxxx and the components are dated 2014 / 2015.I was not able to find any schematics for this version. The only schematics I found are from the above mentioned 2000s Agilent version, but it looks like a lot has changed since then.Does anybody happen to have a schematic for this newer version?From the newer Keysight manuals which cover the later versions with serial MY53xxxxx (but not MY56xxxxx unfortunately), it is mentioned that error code 609 means that the ADC reported some errors back to the CPU. So my hope is I can track down the issue beginning from the ADC. Somebody already tried to change it apparently, there is an AD7192 with datecode 2241 soldered in quite badly - hopefully it is the correct part at all.For now my plan is:- Clean up & resolder the ADC- Check supplies to the ADC- Capture communication between the ADC and CPU

author: openloop
author_rank: Regular Contributor
timestamp: May 12, 2023, 10:11:15 pm
content: ADC error most likely is a red herring.Check power rails on voltage/current op-amps. Common failure point.

author: coy
author_rank: Contributor
timestamp: May 14, 2023, 06:11:26 pm
content: Quote from: openloop on May 12, 2023, 10:11:15 pmThanks for pointing that out.I did my test steps and checked communication between the µC and the ADC, and indeed it turned out the ADC has the error bit set.Apparently the analog input AIN1 is too high (5.2V - which is above the specs). Have to track down now where this is connected to.

author: coy
author_rank: Contributor
timestamp: June 02, 2023, 04:17:39 pm
content: I managed to repair this PSU.The root cause was that the TL074 (U127 in the old schematics, U7 on my board), which is connected to the sense inputs, died for any reason, generating full negative output on pin 8 (-14V), causing erroneous input to the next stage(s) and finally to the ADC (AD7192), causing the ADC error.After replacing the TL074 and recalibration everything looks fine now.Thanks for your help, glad I've saved this from being scrapped.
Keysight E3649 PSU CH2 cannot adjust  - Page 1
Forum section: electronics / repair

author: View[+]Finder
author_rank: Unknown
timestamp: May 26, 2025, 04:35:47 am
content: I have a new used Keysight E3649 PSU, CH1 works as it should, CH2 cannot be adjusted. PSU passes long test, no errors. No obvious damage inside or out. No output at all from CH2. Not even with Track on.Any help will be appreciated.

author: IanJ
author_rank: Unknown
timestamp: May 26, 2025, 02:36:28 pm
content: Hi,E3649 PSU repair on my YT Channel:There's also some other Agilent PSU repairs on my channel also. I usually explain the schematic when I carry out the repairs so you should be able to glean some info applicable to your fault at hand.Ian.