hybridfree/eevblog-posts huggingface dataset:
Repair of Anritsu S331D - Page 1
Forum section: electronics / repair

author: evgar
author_rank: Newbie
timestamp: April 09, 2024, 08:20:20 am
content: Hello everyone!I got an old device Anritsu S331D, It is battery does not hold a charge, there are spots on the screen, calibration is offcan it be repaired?

author: geggi1
author_rank: Frequent Contributor
timestamp: April 09, 2024, 04:27:38 pm
content: It is a dot matrix screen so you might be able to get a sililar if you can figure out resolution and get one with the same driver.I have one with similar poblems and changed the screeen with one form an older unit and it did work.

author: evgar
author_rank: Newbie
timestamp: April 10, 2024, 05:05:39 am
content: Quote from: geggi1 on April 09, 2024, 04:27:38 pmThank you, but where can I find such a screen?

author: vishaldotgupta
author_rank: Regular Contributor
timestamp: April 18, 2024, 07:05:20 am
content: yes repairs are possible. screen needs to be replaced if this is bothering you. as such there are not many spots, you can continue using it. you may be able to add a color screen to it it the hardware allows it
Repair of Danby DDR251DE dehumidifier - control panel hung - Page 1
Forum section: electronics / repair

author: cdev
author_rank: Super Contributor
timestamp: August 25, 2021, 01:01:17 am
content: My basement dehumidifier shows the humidity but wont control the dehumidifier. The sensor appers to be working but all of the control buttons are non-functional. And I cant find a service manual anywhere. Does anybody here have any experience with dehumidifiers?i guess tomorrow I'll just crack it open and take a look at the caps. Its getting to be about that age and its spent a lot of time running. Has anybody else encountered this problem? The motor seemed to be healthy nd a few weeks ago it was working fine, sucking around one or two llters of water out of the air each day.Basically it turns on the panel lights up showing the humidity, say "70" But pressing any of the buttons is failing to do anything at all and it'd panel is frozen as far as functioning. So it never starts to cool. Nor can the RH setting be set.I am wondering if it might be a capacitor, that seems quite possible.
Repair of Datron Switches (i.e. 4000A, 1061, ...) - Page 1
Forum section: electronics / repair

author: meandeev
author_rank: Regular Contributor
timestamp: August 23, 2020, 09:16:35 pm
content: I bought a Datron Calibrator that has some some broken black switches (besides a lot of dirt and other issues).Because these switches are hard to get and expensive, I decided to open a defective one:one can see that the little "handle" is broken, were the spring should be attached.to form a new "handle", I used a hot wire (0.5mm diameter) and put it into the plastic, so that it goes through the other side, melting the plastic.After attaching the spring to the wire, the switch is ok again!Maybe this helps someone, who cannot get/afford these switches.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: August 23, 2020, 10:17:38 pm
content: Try this one:https://de.farnell.com/nsf-controls/623300-001-060-010/switch-spdt-green-led/dp/1165219You can download NSF catalogue page from farnell as well and find part number.

author: maginnovision
author_rank: Super Contributor
timestamp: August 24, 2020, 11:54:49 pm
content: We had a small group buy some time ago for 4000 switches. The light up ones are available through digikey, probably distributors near you too.
Repair of dead channel on Rigol DG1022 - Page 1
Forum section: electronics / repair

author: thomaspfenning
author_rank: Newbie
timestamp: August 20, 2022, 10:02:05 pm
content: Here is my experience. For some reason my dg1022 ch1 died after using one time. I was able to use ch2. Then decided to see if I could fix ch1 after realizing I was beyond the warranty period. First thing to check was whether schematic and parts were available. No way, since the soic-8 ic used for the output had the numbers ground off. How thoughtful of them Chinese. But being used to these shenanigans , I mapped out the pin connections and measured voltages on the good and bad channels. From this I deduced that they were just using a high performance op amp. Went to the digikey op amp selector and filtered out all chips that would not work. ended up with only a couple choices. The THS4631D met the criteria and I installed. Yea, it worked. Only problem was I got the version without the thermal pad. I put high performance thermal paste on the bottom of the chip and added a large aluminum heat sink on the top . To test I ran ch1 at 5v with 1 Mhz square ware into 50 ohm to thermal equilibrium, and cycled a few times.The square wave was almost ideal and only dropped 50% when going from no load to 50 ohm which is correct. If you try this fix please let me know.Thomas Pfenning
Repair of DELL Latitude E5570 motherboard - Page 1
Forum section: electronics / repair

author: dzseki
author_rank: Frequent Contributor
timestamp: March 12, 2020, 11:31:28 am
content: At work we wanted to program an FPGA board with an Altera USB Blaster and using a DELL Latitude E5570 laptop.The FPGA board is rather complex and it seems something seriously went wrong with it. Upon powering up, the FPGA board seemengly took out the USB Blaster, in turn the USB Blaster took out the laptop as it went dark immediately -go figure!The laptop is not switching on anymore, more precisely if we push the power button the power on LED comes on for 20 seconds or so, but nothing else happens.I have disassembled the laptop and found out that with two out of the three USB connectors have the data+ and data- legs (of USB 2.0) shorted to ground (through ~2 Ohm).On the data lines there was a surge protector diode, I hoped it was that easy, removed to no avail. The short remained.I have traced these lines to a QFN16 device marked „sZZHE”, again I hoped after removing this the short would go away, but again no.So I am curious how USB is done on modern(ish) computers. This one has an I5-6300U CPU which contanis pretty much everything in one BGA package soldered on the motherboard.

author: SilverSolder
author_rank: Super Contributor
timestamp: March 13, 2020, 05:40:37 pm
content: I know this is too late... but there is such a thing as a USB isolator!

author: dzseki
author_rank: Frequent Contributor
timestamp: March 13, 2020, 09:00:15 pm
content: Yes, we realized this too -just a bit too late eh...Anyway I was able to find a DELL schematic diagram that was also a Latitude series, but a few years older. Anyway it was very similar to what I saw. The USB data lines are protected with ESD surge arrestor diodes and with a common mode coil, the mystic IC was probably a multiplexer that is used to decide how much current should the USB allow for the device. Other than that the data lines went in to the chipset on the old schematic, in our case there is not even a chipset IC anymore, everything is integrated into the CPU, the CPU on the other hand is soldered on the motherboard, so that was about it...
Repair of Digital Clock Radio that time drifts. (Sanyo RM-6018) - Page 1
Forum section: electronics / repair

author: crunch
author_rank: Newbie
timestamp: February 03, 2020, 10:34:36 pm
content: I have a Digital Clock Radio (Sanyo Model RM-6018) that is about 10 years old and that recently began to time drift quite drastically, Up to 10 minutes a week compared to my wifes one (completely different make and model) on the other side of the bed.I was wondering if anybody had suggestions on what could have gone wrong within it that might make it drift like this.I don't think its the mains frequency because the other clock, which still maintains accurate time, is on the same power circuit as the time drifting clockWe do have solar power in our how which appears to maintain a reasonably consistent frequency, but again, I would have expected if that was the cause it would cause the working clock to drift as well.Are there standard components which fail which could easily be replaced to see if it fixed the problem? if so how easy are they to identify and replace?Hopefully I have given enough information for somebody to make repair suggestions etc.Regards,David

author: fzabkar
author_rank: Super Contributor
timestamp: February 04, 2020, 01:30:00 am
content: Disconnect it from the mains and connect a DC power supply to the battery terminals. Monitor the time over 7 days. This will isolate your AC supply and solar inverter.If the problem turns out be related to the AC frequency sensing, there will usually be an optocoupler which squares up the rectified AC pulses and feeds them to the uC. You might like to compare the circuits in the two clocks to see how they do this.BTW, does the clock run slow? If so, then it must be dropping pulses.

author: xavier60
author_rank: Super Contributor
timestamp: February 04, 2020, 03:37:18 am
content: I have seen the odd clock radio advance in time. It was because spikes on the mains were reaching the reference input on the clock IC and being counted. Putting an appropriate sized capacitor between the input pin and ground cured the problem.

author: fzabkar
author_rank: Super Contributor
timestamp: February 04, 2020, 03:44:56 am
content: Maybe this (Zellweger Off-Peak Signalling)?https://goughlui.com/2014/02/02/project-analyze-mains-power-flicker-issue-ripple-signalling/

author: Haenk
author_rank: Super Contributor
timestamp: February 04, 2020, 07:16:26 am
content: Maybe check your mains frequency.Most cheap radios use 50Hz or 60Hz mains frequency as a base for the timing.This has been quite an issue in Europe about two years ago.In German:https://www.heise.de/newsticker/meldung/Zeit-Synchronisation-per-Stromnetz-Energieknappheit-laesst-Uhren-nachgehen-3984126.html10 Minutes a week seem to be a lot though, might be something completely different...
repair of fluke 175 - Page 1
Forum section: electronics / repair

author: anuragagrawal
author_rank: Newbie
timestamp: November 19, 2020, 06:56:16 am
content: i need help on my pcb parts, pls give details if any body have about ths part in red mark.thanks in advance

author: mzacharias
author_rank: Frequent Contributor
timestamp: November 19, 2020, 03:21:35 pm
content: Looks like a small value capacitor, associated with the high current range.What is the problem you are having?

author: retiredcaps
author_rank: Super Contributor
timestamp: November 19, 2020, 10:00:40 pm
content: Yes, what is the problem you are having?Inductor? Seehttps://www.eevblog.com/forum/repair/fluke-179-76688/
Repair of Hever Level Generator - Page 1
Forum section: electronics / repair

author: johnh
author_rank: Regular Contributor
timestamp: August 05, 2020, 09:09:08 am
content: Found Heuer LG11 Level Generator 200 Hz to 4000 Hz in the skip at work a while agohttp://www.heuer.com.au/tmsa11/lg11.htmlIt was little beaten up, scratched missing the battery holder and door. Some had attacked the torx screws with a hacksaw so they could use a flat bladed screwdriver.It comprises three board. The front panel has display and other controls processor card and the output cardAfter pulling it apart you could see that the batteries must have leaked at some stage. Replaced the battery connector and replaced 4 AA battery holderMade a new battery compartment door from a blank PCBFrom the specsFrequencyRange30 Hz to 20 kHzResolution1 Hz:30 Hz to 1 kHz10 Hz:1 kHz to 20 kHzSpot Frequencies200 Hz, 300 Hz, 400 Hz, 600 Hz, 820 Hz, 1020Hz, 1200 Hz, 1600 Hz, 1800 Hz, 2000 Hz, 2400Hz, 2700 Hz, 3000 Hz, 3400 Hz, 4000 Hz
Repair of HIOKI 3522  - Page 1
Forum section: electronics / repair

author: azemati
author_rank: Contributor
timestamp: November 11, 2020, 09:17:49 am
content: Hello guysWe have a Hioki 3522 LCR meter,But unfortunately its LCD has horizontal lines.Can you help me with which IC this problem is related to?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: November 12, 2020, 01:08:59 pm
content: Those IC's are probably the LCD drivers, and not much more then glorified shift registers, and they're usually not the weakest spot.As far as I know the most common fault with LCD's with the connection of the glass and the PCB.What happens if you stroke your fingers over the edges of the PCB and LCD?

author: Koray
author_rank: Regular Contributor
timestamp: November 12, 2020, 03:35:23 pm
content: I think it is just contacts are not good. I would bend the tabs of the metal frame to release it and clean the zebra strips, lcd, and the board contacts with IPA. Then reassemble and it should work.K.

author: maple
author_rank: Newbie
timestamp: November 27, 2020, 03:17:34 am
content: I just bought one with the similar problem. It will be delivered in a couple of days. This problem is very common in old LCDs which is not caused by damaged IC. One of the main reasons is open circuit between PCB and LCD glass panel. This LCD could be replaced with some similar 320240 LCDs.
Repair of HP 8569B 22GHz Spectrum Analyzer - Page 1
Forum section: electronics / repair

author: Jamie_A
author_rank: Contributor
timestamp: November 07, 2023, 05:09:29 am
content: I'm attempting a repair of my newly acquired HP 8569B Spectrum Analyzer.I'm seeing a terrible response in bands 2 to 6 (harmonic mixing). See pictures.I have a working 18GHz SA and good signal generators to compare against. I believe I narrowed down the issue to the 1st mixer. I see a similar results when bypassing the fronted and injecting a (-30dBm) signal directly into the mixer. I confirmed the bias generator is nominal, and the LO is strong and flat. Additionally, I injected in a 321.4MHz IF signal into the SA, bypassing the mixer, and got a perfect flat trace.The only suspect bias signal is the "Drain Bias" powering the IF amplifier in the mixer assembly. It is drooping to 4.6V with the mixer attached, with the mixer drawing 77.45mA into the turret. Disconnecting the mixer shows that rail raise back up to 5V (due to the series resistance in the bias supply). This means the IF FET is dissipating 1/3 W!The other bias voltages are nominal.Testing with a spare (used/untested) 1st mixer shows exactly the same result.Does anyone have a working 8569B? Could you possibly measure the voltage on the Drain Bias of the 1st mixer? I have no reference to go off of, and the OSM for this unit is not as detailed as the 70s era HP gear.Any idea what else could be going on here?

author: Jamie_A
author_rank: Contributor
timestamp: November 08, 2023, 06:47:59 pm
content: Looking inside the mixer, not any visible damage. You can see the PIN diode and mixing diode next to each other. The small die to the west of the them is the IF FET.

author: Jamie_A
author_rank: Contributor
timestamp: December 04, 2023, 05:37:48 pm
content: It turned out to be an YTO issueThe level was 10dB too low (around 4dBm). Interestingly the level at the front panel LO output was almost in spec, which threw me off.After replacing the YIG, I ran through the YTO calibration, and the YTF tracking calibration procedure. Now it's running beautifully.
Repair of HP/Agilent 1670G Option 3 Board - Page 1
Forum section: electronics / repair

author: Meown_12
author_rank: Newbie
timestamp: October 10, 2020, 08:16:28 pm
content: Hi everyone,I recently aquired a 1670G Logic Analyzer with the Scope option (Option 3) from ebay with a claimed power supply problem. Disassembled it to get to the PSU checked its rails, which where all good, no sign of smoke that the seller mentioned, and reassembled it. So I powered it up, only to be greeted by a singular plume of magic smoke but the device powering up and showing the menu just fine. Foolishly, after the smoked cleared I turned it back on - no more smoke and the LA passes its selftests apart from Timebase, D/A and A/D ones from the Option Card. As the option card was buried so deep I had to take all the insides out I didnt do it immediately - welp, should have done that. Upon checking it I found that one of the tantalum caps had completely explosively disintegrated, most likely an initial burn with the previous owner, which I invited for a sequel during my ownership.See:Now I am wondering, after seeing the board underneath:Can this be repaired? I thought of jumpering the 2 (freshly bought, same brand) caps back in and hoping none of the signal lines are bad (the ones visible on the underside going around E64 and E62 I was able to verify continuity on), but I dont have any schematics for the board so I can only guess at where they were supposed to go.Would the slightly mared capacitor C97 on the underside also be a candiate for replacement?My post ends with two questions:- Does anyone know of a place where the board level service manual / the schematics for this board (hp 01660-66527 Rev A) can be found, google turned nothing up for me on the general service manual or the board level one.- Is there a place where one could get the whole board as a replacement part? I have seen the hp 01660-66526 on ebay, which I assume is the pattern generator card but I couldn't find a scope card aroundAny suggestion or advice on this is greatly appreciated,Thanks

author: sarnau
author_rank: Contributor
timestamp: April 02, 2025, 09:34:31 pm
content: It's a bit late, but maybe it helps others. I have a similar issue with the scope. However the PCB is still acceptable. I've removed the 2nd cap next to the blown one and they are just in parallel. I've attached some detailed photos.

author: ZGoode
author_rank: Frequent Contributor
timestamp: April 02, 2025, 10:27:11 pm
content: I ran into a similar problem when trying to fix my 16911A cards. Unfortunately, it seems Agilent (now Keysight) had and still have no intent on releasing board level schematics or repair guides for these pieces of hardware. Unless you can find someone who is familiar with these boards (or a technician at Keysight familiar or willing to leak info), you might just have to figure it out based on what other people have done

author: sarnau
author_rank: Contributor
timestamp: April 03, 2025, 05:13:54 pm
content: I would assume that the original developers are long gone/retired and that that information was lost during all the company transitions…
Repair of Kewtech K71 PAT - Page 1
Forum section: electronics / repair

author: Big JJ
author_rank: Newbie
timestamp: June 05, 2020, 02:55:20 pm
content: HiI have been working on a KT71 Pat tester, which powers up past self test but will not do anything when buttons pressed.I have fixed quite a few of these over the years but this one is harder. Previous were power supply related etc.Does anyone have a schematic for one of these. Kewtech tell me they will not provide and they no longer repair them.So, more land fill if I cannot fix it.
Repair of Lecroy 9314CM Scope Trigger Level knob - Page 1
Forum section: electronics / repair

author: danielle.decesaro@micropr
author_rank: Newbie
timestamp: May 23, 2022, 01:17:58 pm
content: Hi everyone,I am in need of some help. I have a Lecroy 9314CM scope that has a snapped potentiometer shaft for the trigger level. Does anyone know the Bourns model replacement? I can't seem to find a schematic for this unit.Thanks

author: Stray Electron
author_rank: Super Contributor
timestamp: May 23, 2022, 01:42:53 pm
content: Are you sure that that is a potentiometer and not a rotary encoder? I don't still have the number available but I have posted the Bourns part number for the rotary encoders used in the 935x scopes several times over on the LeCroy groups.io list. They used two different encoders and IIRC the only different was that some made a slight click when you rotated them and the others didn't.A word of warning!!!! The plastic front panels in all of those old LeCroy scopes are old and dried out and brittle and it you try to take them apart, they will must likely crumble and you won't be able to reassemble them. So absolutely don't take the front panels apart if you can avoid it. Try and make the repair from the outside. Several people have managed to repair the sheared off shafts in situ, take a look around the internet and on Groups.IO.

author: edpalmer42
author_rank: Super Contributor
timestamp: May 23, 2022, 04:07:28 pm
content: I have a LeCroy 9384L. I don't know if the front panels are similar, but for mine, the relevant part numbers are:Detent: ECW1D-Y32-BC0024Non-Detent: ECW0D-Y32-BE0024Of course, both were discontinued about 10 years ago.I thought I had a dead decoder on mine, but it turned out to be a solder bridge from the factory! No wonder this unit had no screen burn. It didn't work right and they just put it on the shelf instead of returning it.Many years ago I fixed an HP 8647A Signal Generator. I disassembled the HP-branded decoder and used JBweld to attach a piece of aluminum rod to the stub to replace the shaft that was missing. I don't know if the Bourns units can be disassembled.

author: danielle.decesaro@micropr
author_rank: Newbie
timestamp: May 23, 2022, 09:12:54 pm
content: When I messaged the manufacturer they could only tell me the part is obsolete and that it is a smooth (w/o detent) digital encoder.If anyone can give me the correct Bourns model replacement for this part I would appreciate it.
Repair of NEFF (Bosch/Siemens) electric hob - T14T82N0 - Page 1
Forum section: electronics / repair

author: kaz911
author_rank: Super Contributor
timestamp: August 31, 2022, 01:11:39 pm
content: Hi,I just completed a very simple repair of our NEFF T14T82N0 Electric Hob. As Siemens and Bosch usually have the same "products" with slightly different topside designs - it will probably apply to any of the brands older touch based hob units. Might even be applicable to many other BSG Group touch products as they are quite good at product/design re-use.The error on the NEFF hob was led's was just blinking dashes "-" occasionally - and touch interface was unresponsive.Offender was as ... another dried out capacitor branded Yageo SJ 470uF 25v 105 deg. It had a slight bulge. It sits close to the touch flat cable connector on the DC side of the controller mainboard.As my lab is not "up" (its in storage) I had to run out to get a new capacitor from a local component pusher. So I could not get one with quite the "longevity" of the Yageo - but so far it works.But a welcome surprise from the repair is now the touch interface on the hob isa LOTfaster to use.Seems like the Capacitor have been on the fritz for a while. As we never had that type of hob before we moved into the house - we had no idea how it was supposed to work.As the hob has a slightly stupid and unique size - the only replacements that would fit directly in the cutout and available space was all priced > £1500.But repair was less than £1,- in materials (ex my time) - so quite a few kg of CO2 saved from unnecessary purchase of new hardware./k
Repair of  R&S ZVB-8 ( 4 Port )  thats not powering up. - Page 1
Forum section: electronics / repair

author: EI3IFB
author_rank: Newbie
timestamp: October 13, 2025, 11:48:34 am
content: New member here to the EEVblog community !I have just acquired an R&S ZVB-8 (4 Port) VNA in overall good condition that's not powering up.My first port of call is of course the PSU and would welcome any tips from someone that has experience with this particular unit i.e. any stock faults , common issues peculiar to this model , any gotcha's or things to look out for etc . I have a soft-copy of the Service Manual and a well equipped Lab. Just want to learn from other folks experience in repairing this and "not reinvent the wheel " as it wereSteve.
Repair of SDS2104 - Page 1
Forum section: electronics / repair

author: gregfox151@gmail.com
author_rank: Contributor
timestamp: November 20, 2024, 09:16:28 pm
content: Hi all, My Channel 1 went flatline on this SDS2104, all the others are ok(2-4).I found this Cap to be open when removed and was hoping someone would know what the value is.Many Thanks!

author: KG7AMV
author_rank: Frequent Contributor
timestamp: November 20, 2024, 09:56:56 pm
content: I would just pull one from another channel and measure it.

author: gregfox151@gmail.com
author_rank: Contributor
timestamp: November 20, 2024, 10:02:15 pm
content: thanks for the reply, not so easy, I almost pulled the pad on this one and would hate to screw up another channel.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 20, 2024, 10:13:55 pm
content: Tweezers are needed. Or simply add Rose alloy and blow hot air.

author: tautech
author_rank: Super Contributor
timestamp: November 21, 2024, 11:02:46 pm
content: Quote from: gregfox151@gmail.com on November 20, 2024, 10:02:15 pmIt will be that awful lead free solder so dilute it some with leaded solder.Check what the cap connects to and if it's a power rail to the IC's it's likely local bulk storage or decoupling so a 10uF MLCC might be a substitute but pull another to check.

author: gregfox151@gmail.com
author_rank: Contributor
timestamp: November 25, 2024, 10:46:38 pm
content: It seems the problem was solved simply by pressing the default button! It wasn't the Cap at all.
repair of  soldering iron 8878D rework station (exploded ground trace)  - Page 1
Forum section: electronics / repair

author: Sylvia
author_rank: Newbie
timestamp: July 12, 2019, 07:55:39 am
content: I am pretty new to the world of electricity. Before I attempt to repair this soldering iron i want to find out why it happened.I was just soldering and just at the moment where I put the iron in the stand, which is standing on my ESDmat, I heard a loud pop! And the circuit breaker cut out!Coincidence? Or some sort of smps leakage thing?When I got the iron(two month ago) I tested the tip continuity to ground, and got about 4ohms if I remember correctly. The wire on the picture is to measure continuity( my solder joints normally don't look like this but my other iron is faulty and doesn't get up to temperature). I measured again continuity between tip and earth plug and it beeps, so I think the first time I didn't apply enough pressure.What I don't understand is how so much current has flown to vaporise the trace through the 1Mohm R in the mat, and where the difference of potential is coming from. The fuse in the soldering iron is not blown, but the breaker in the house cut off.Even if I don't repair this one I what to understand what happened because when I buy a new one I have to know if a Transformer is better.Has this some thing to do with smps?

author: dial-a-monkey
author_rank: Contributor
timestamp: May 09, 2024, 11:54:48 pm
content: Exact same thing happened to me.. also the rectifier diodes blew up at some point - but it is for electronic repairDoes anyone know the specifications for the soldering ceramic element and hot air element?I need to order replacements from Europe but don't have time to wait to get the part from China..Is the soldering iron ceramic element is 1321? 1322? or or 1324? ( i emailed the manufacturer Yagong but no reply)it'a definitely 24 VAC measured with the power on, the length seems ~ 60 mm (but mine is broken) x 3.8 mm diameter - I don't know the watts i thnk i read the specs as 60 watts but the 1321 ( most likely fit ) is 63 mm
Repair of Sony Watchman FD-2E - Page 1
Forum section: electronics / repair

author: 4x1md
author_rank: Regular Contributor
timestamp: October 16, 2020, 03:25:38 pm
content: I'm repairing an old Sony Watchman FD-2E handheld TV. I would appreciate any help on two questions.1. I have a service manual for this model. My unit has an additional PCB with TA7370P IC which doesn't appear in the schematics. I don't understand why a TV with mono sound would require a stereo decoder IC, but this is a Sony PCB which fits perfectly the space behind the picture tube. It doesn't look like a modification made by the previous owner. Does anyone have an updated service manual or schematics of a similar Watchman device with this IC?2. The unit has a faulty power supply IC CX0159. It looks like it had been connected to a DC source with a reversed polarity or to a high voltage. Is there any chance to get this IC without buying another unit for parts?

author: magic
author_rank: Super Contributor
timestamp: October 18, 2020, 06:56:19 am
content: Quote from: 4x1md on October 16, 2020, 03:25:38 pmWithout knowing the specific part you asked about, I would say- look for brick and mortar electronics shops that used to supply TV repairmen back in the day; here some of them are still around and some are selling their stock by mail too- eBay, preferably not from China- eBay China and AliExpress, but test the part as much as possible before installing on a board you care about - these will likely be recycled and they may be fried or even a completely wrong chip

author: 4x1md
author_rank: Regular Contributor
timestamp: October 18, 2020, 07:57:45 am
content: Ordered the IC from a seller in Greece.The unit has many tantalum capacitors. How often do they fail? Is it a good idea to replace them all together? Is it safe to replace them with MLCC of the same value?
Repair of Tektronix DPO4104 scope - Page 1
Forum section: electronics / repair

author: richarde
author_rank: Newbie
timestamp: October 20, 2018, 10:25:53 am
content: We have recently acquired a Tek DPO4104 (for spares) but found that the instrument had been deliberately damaged. All five BNCs for the 4 channels and the Aux In (and many of the other connectors) had been attacked with needle-nosed pliers. Having dismantled the unit we can see that a repair should be relatively simple by replacing the BNCs but we have been unable to identify the specific manufacturer/part. They are a rather unusual extended, vertical, through-hole pcb mounted, panel or bulkhead mounting, 50 ohm jack (see photo). The jack is 31.2mm to the pcb surface, 24.6mm to the shoulder "bumps" for the mounting surface and 18mm to the start of the threads. The second photo (from another post) shows the jacks in situ with the panel mount clamping to the shield cover.Tektronix (of course) say that the BNC jacks are not availabale as a spare part and the entire board needs to be replacedAnyone know who the manufacturer of the jack might be or know the actual part number? Thanks

author: TiN
author_rank: Super Contributor
timestamp: October 20, 2018, 11:42:07 am
content: They don't look too bad on your photo.I have donor DPO4034 board, so we can make a trade. I'll send you BNC connectors, in return of shipping cost and hi-res photos of your DPO4104 board.Photos of the front-end under cans would be greatly appreciated. To remove cans you need desolder two tabs of the back can to free it from the PCBA. Front can held just by BNC mounts.My donor board:

author: richarde
author_rank: Newbie
timestamp: October 21, 2018, 10:56:05 am
content: HiThanks for your reply. That certainly works from my standpoint if it does for you? PM me the cost and how to get it to you or I may be able to arrange for (say) UPS to collect?We have already removed the shielding cans and I can take some "tiles" of the board at high res and put them up in a "Box" folder and then publish the link? or PM you?Although our connectors don't look damaged from the angle of the photo I took before (which was to illustrate the form factor of the Tek BNCs) they are pretty mangled (see new photos)We are also (potentially) looking for a functioning I/O board for one of these units as one of our other DPO4104s has a dead I/O board. (see the photo of the whole unit for the USB and CompactFlash connector layout. Later units had a different arrangement.)

author: Samogon
author_rank: Frequent Contributor
timestamp: October 22, 2018, 12:54:47 am
content: I wonder did you try to test if acquisition board is ok?

author: richarde
author_rank: Newbie
timestamp: October 23, 2018, 08:23:41 am
content: The initial checks seem to indicate that it is, but with the damaged connectors we weren't able to give it a full quality check

author: rainbow
author_rank: Contributor
timestamp: July 27, 2024, 01:52:40 pm
content: Hi,in the mean time someone has found a compatible BNC connector or the parts number of the original?thanks
Repair of Tektronix DPO/MSO4000/B O'scope - Page 1
Forum section: electronics / repair

author: mikehank
author_rank: Regular Contributor
timestamp: September 29, 2022, 03:41:17 pm
content: Hey Guys,I have lots of experience working on these scope. If you need help and/or advice ask here and we will try to help.

author: OYAZI
author_rank: Newbie
timestamp: October 14, 2022, 12:27:23 am
content: Hello,Do you have any idea to repair front panel intermittent (chattering??) encoder?(VOLT SCALE, POSITION etc.)I tried to cleaning the contact.(Ethanol, Electrical contact cleaner), Cotact grease...The good result was not obtained.

author: OYAZI
author_rank: Newbie
timestamp: October 14, 2022, 12:46:22 am
content: I forgot to write.A model name is DPO/MSO4000 series.

author: mikehank
author_rank: Regular Contributor
timestamp: October 14, 2022, 04:22:53 pm
content: Hi OYAZI,The way I have fixed encoders jumping around is to exercise them. Get a electric screwdriver or drill and spin fast in one direction for around a minute then another minute in the other direction. This will fix I would say 75% of the issues. If this doesn't work the encoder will need to be replaced.Thanks.

author: OYAZI
author_rank: Newbie
timestamp: October 17, 2022, 06:44:52 am
content: Hello,Thank you for your reply.I will Try....

author: analogRF
author_rank: Super Contributor
timestamp: July 08, 2023, 01:12:12 pm
content: Quote from: mikehank on September 29, 2022, 03:41:17 pmHiCan somebody confirm whether in DPO4034B the +1.5V rail (in the row of power supply test points) is up and running after turning on the scope?I have a DPO4034B stuck at splash screen and the remedies mentioned in this thread didnt help. However, I noticed that all power suppliesare ok except that +1.5V which reads ZEROI have spent a couple of hours trying to trace that rail to where it is generated and/or where it is used with no luckI am beginning to think that maybe it just does not exist on 4034B and only exists on MSO or 4104B or on MDOs?I do not see it being used anywhere on the board except by an uninstalled chip.Still I could be totally wrong and have not seen its origin.

author: mikehank
author_rank: Regular Contributor
timestamp: July 09, 2023, 01:17:54 am
content: The 1.5V rail is used for the MSO-Band MDO(non B) scopes. I believe its used for the digital threshold compariter used with the 16 digital inputs. The DPO's will not have this chip. If you can post the boot script it would be very helpful in reparing this scope. Also look at the on off let on the front panel. Should be orange when plugged in but off. Green during operation and boot if all is good.

author: mikehank
author_rank: Regular Contributor
timestamp: July 09, 2023, 01:38:00 am
content: Also check each of the test points to ground. I cant remember the correct resistances but none should be anyware close to short.
Repair of Tektronix P6231 Z0 probe tip - Page 1
Forum section: electronics / repair

author: 44kgk1lkf6u
author_rank: Regular Contributor
timestamp: September 29, 2024, 12:00:53 am
content: I got a Tektronix P6231 variable offset Z0 probe. It had no tip. This is how I repaired it. The procedure should work for other 2.5 mm subminiture Z0 probes such as the P6156.The part number for the tip is 206-0279-00 or 206-0279-10. I failed to acquire one.I found an SMA connector for RG-174 cables. I cut a #5-44 thread on the part for crimping the shielding. I had to grind the face of the die so the thread could go close enough to the connector body. My connector was big enough. This part on some connectors may be too small. I replaced the stranded center conductor in a piece of RG-174 cable with a piece of solid 24 AWG wire. I bent it slightly so it made good contact with the hole in the probe. This way I converted the connector for the probe tip to SMA.I got an edge-launch SMA connector. I put in a piece of FR-4 without copper clad to make soldering easier and also to make the pin more rigid when glued. I shortened the center pin. I connected a 0402 size 402 Ω resistor and a pin to it. I applied epoxy. I added a pogo pin for the ground connection.It had enough bandwidth for my 1 GHz oscilloscope. I got no overshoot when measuring a square wave with edges faster than the oscilloscope can measure.For other ways of making Z0 probes with an SMA port, one may also want to look at the stuff named akl-pt from this link (not mine).https://github.com/azonenberg/starshipraiderThere is a video reviewing it.
"Repair" of the LCD backlight of a Agilent U1272A - Page 1
Forum section: electronics / repair

author: nightfire
author_rank: Frequent Contributor
timestamp: March 11, 2023, 12:10:27 pm
content: Situation: Wanted to check some LEDs on a repair project, grabbed my U1272A, switched it on and wanted to engage the backlight, because it helps me with clear reading. Nothing happened, only confirmation beep that the setup/light button was pressed. No error message. Setup worked fine, also reset to defaults worked.What to do?Battery on the LCD still read three stripes, so should be full. Measured the 4 AAA cells with a bench DMM, 1.45V open circuit voltage. So, not totally good, but on an acceptable level.Dismantled the whole PCB, unscrewed everything, separated the LCD module from the PCB, which is very nicely realized in this DMM.Measured with a Fluke 8600A bench DMM in diode mode the LEDs, got 1.77V, so theoretically it should be ok.At that point I wondered if I should adapt some connectors to make the LEDs light up, or simply try fresh AAA cells first to rule out other complications.Put in 4 fresh Varta Professional cells, and all of a sudden the backlight worked again.Stupid moment, but maybe helpful as a reference for other people who encounter similar symptoms with their DMM...

author: Swake
author_rank: Frequent Contributor
timestamp: March 12, 2023, 08:31:35 am
content: Yeah... they look nice on paper. Not many that sell them anymore. Has to be a reason for that. The OLED debacle didn't help.

author: nightfire
author_rank: Frequent Contributor
timestamp: March 12, 2023, 12:07:11 pm
content: The U1272A has the classic LCD display, OLED would have been the U1273 model.As it seems, HPAK decided to retreat from portable multimeters, at least here in europe- I wonder if this is due to some internal restructuring, focus on business customers etc.?Or maybe lack of qualified personnel to really develop and maintain multimeters? Or never reached a decent marketshare?( I mean, here in germany, professionals in industrial environment know Fluke as premium brand, and Gossen Metrawatt that is somewhat prominent)

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 12, 2023, 01:24:20 pm
content: U24 seems a charge pump. I'd start by measuring the outputhttps://www.flickr.com/photos/eevblog/5739204826/in/album-72157626761928610/.
Repair of TS100 - Page 1
Forum section: electronics / repair

author: TheAmmoniacal
author_rank: Unknown
timestamp: October 03, 2020, 10:32:25 am
content: I accidentally used a 24 VAC output wall wart to power my TS100 and now the power regulation do not work. If I connect a power source to the iron the full power is now going to the tip continuously.Any good guesses of where I should look? Maybe the CJQ4953?I have attached what I believe is the TS100 schematic.
Repair of Yamaha A-700 amplifier - Page 1
Forum section: electronics / repair

author: Emil88d
author_rank: Contributor
timestamp: December 06, 2019, 02:20:54 am
content: Hello, can someone help me with repairing old yamaha?🤔 I would like to repair this amplifier to learn a Little about electronics but i dont know how to start. When i buy it it has broken transistor 2SC1815 and smoked resistor 1.5k ohm and i replace them and try to power on through lamp and it started then i pluged fuse and the resistor started to burn. I discontcted power source from the main board and measured the voltage on the 2 big capacitors and it was + and - 58,6vCan someone help me what i need to check more to find what coused burning of the resistor.I am adding the schematic and the picture where the parts was damaged.

author: PKTKS
author_rank: Super Contributor
timestamp: December 06, 2019, 10:22:02 am
content: There is no magic or fancy solution hereAll discrete boards require testing each component per siIt seems you do have a dead shortA common "fit all" solution is to power the boardwith a variac.. raising it enough to not burn...But enough (via CC/CV control) to hot spot the dead short culpritToday thermal cameras are handy..10y ago we just put some vapor like fluid or alcoholyour finger sometimes...Paul

author: PKTKS
author_rank: Super Contributor
timestamp: December 06, 2019, 10:32:08 am
content: and BTW.. there is a SERVICE MANUAL for this classwhich in time was quite complex to diagnose.It helps a lot with proper check points...Paul

author: Emil88d
author_rank: Contributor
timestamp: December 06, 2019, 11:24:24 am
content: Ok thank you for targeting me to resolve the problem.👌

author: Emil88d
author_rank: Contributor
timestamp: December 06, 2019, 04:43:25 pm
content: I dont find any hot spots but i started to desolidering end transistors and all at the end are shortcircut and even other transistors at this channel so i think it is not worth to buy all of the transistors.
Repair On/OFF-knob on Creative Gigaworks S750 Surround system - Page 1
Forum section: electronics / repair

author: Mijuca
author_rank: Newbie
timestamp: June 22, 2025, 09:04:58 pm
content: Hi everybody! The on/off-knob to my Creative GigaWorks S750 7.1 surround-system has fallen off from the subwoofer box. I used to lean my feet on the box, sometimes unintentionally touching the on/off-knob. The parts that makes up the on/off-switch system got loose at some point after too much touching with my feet, which eventually resulted in the whole knob falling off completely at one point. Now I am unable to turn on the whole system, because there is no more any on/off-switch to turn the system on with. I don t think the knob is broken, it has just disintegrated. I have all the parts that makes up the on/off-knob.Has anybody encountered a similar problem? I have asked the support service at Creative if they have a blueprint of the on/off-knob to the Creative GigaWorks S750 7.1 surround-system, because I was hoping they could provide me with a picture that shows how the parts are attached to each other. As expected, I was told that they are not able to provide this kind of information of the products. The product has been discontinued for a long time ago. Does anybody have any idea of how to put this knob together again?
Repair or recycle? - Page 1
Forum section: electronics / repair

author: canadmin
author_rank: Newbie
timestamp: July 16, 2024, 05:42:56 pm
content: I have a cuisimax air fryer oven that has died after six months of use. Is it worth trying to fix?

author: themadhippy
author_rank: Super Contributor
timestamp: July 16, 2024, 06:30:38 pm
content: if its only 6 months old i'd be wanting it repaired under warrenty

author: shakalnokturn
author_rank: Super Contributor
timestamp: July 16, 2024, 07:36:44 pm
content: Thrash then trash the peice of crap, I've spent most of my life trying to save electronics from the landfill (/export then landfill) all I feel is frustration.Accept that you've wasted money, move on. (Stop using air fryers...)

author: factory
author_rank: Super Contributor
timestamp: July 16, 2024, 09:11:42 pm
content: At least claim a refund firstifit's only six months old, then the seller* can enjoy the sound of it hitting the bottom of the dumpster, where it belongs.* if they ask for it back.David
Repair or scavenge Dell E2213hb? - Page 1
Forum section: electronics / repair

author: timg11
author_rank: Contributor
timestamp: December 09, 2023, 08:08:38 pm
content: I have a Dell E2213hb that has become increasingly unable to sync to video input without power cycles. It will eventually sync and work fine, but it is too annoying to keep going. I've tried other resolutions and shifting timing to the extent my Nvidia control panel allows and it doesn't make any difference.Here's a videoof it spontaneously getting synced up after about 15 seconds. Many times it requires multiple power cycles.So I'm wondering if anyone has seen this issue, and if there is a practical repair?If not, are there any components in this monitor that would be worth salvaging?
Repair Oxmoor "4x4 Buffer" from 1987 - Page 1
Forum section: electronics / repair

author: The_Gecko
author_rank: Newbie
timestamp: June 13, 2025, 04:07:20 am
content: I've got one of these in my possession:http://www.oxmoor.com/files/manuals/4x4%20manual.pdfI knew it was old and that it would need some TLC when I bought it. First time I powered it up, it had a horrible hiss across all four channels. I popped the top and immediately replaced eight potentially leaking electrolytic caps in the output stage and both filter caps in the power supply. The noise floor was lowered, but it's still pretty bad. I could continue replacing caps as there's 32 much smaller ones that I haven't touched. There's also several opamps in sockets that would be a breeze to replace.First question, would you continue replacing caps, or start replacing opamps, or something else?Second question. Given that some of these opamps are no longer in production, are these replacements sufficient? Or have things improved so much in 40 years that I should be considering more modern alternatives?Original OpAmpReplacementNE5532NSA5532PAD711JNOPA134PAAD712JNAD712JNZHere's three photos showing the internals. Left. Middle. Right.The caps circled in purple have been replaced.

author: The_Gecko
author_rank: Newbie
timestamp: June 14, 2025, 01:43:42 pm
content: Volume pots cleaned with DeoxIT F5, no improvement.

author: m k
author_rank: Super Contributor
timestamp: June 22, 2025, 07:25:49 pm
content: I guess I'd remove all sockets.

author: MathWizard
author_rank: Super Contributor
timestamp: June 23, 2025, 02:53:55 am
content: How tarnished do sockets and DIP IC's tend to get over the years ? I'm guessing it's not easy to clean sockets.I'm no audio expert, but I think lots of people still like the NE5532, I've never heard of the other op-amps.

author: JoeyG
author_rank: Regular Contributor
timestamp: June 23, 2025, 05:03:17 am
content: First rule of repair is to check the power supplies.Use an Oscilloscope to check for clean signals on all the voltage supply lines of the ICs.I'm NOT an audio buff, but all the inputs and output probably terminated in balanced or unbalanced?
Repair Philips PM3384 - Page 1
Forum section: electronics / repair

author: ChristophMS72
author_rank: Newbie
timestamp: February 05, 2024, 05:16:47 pm
content: Hello everyone!I'm searching for some help on putting my 4-channel digital scope from Philips back to operation. Some years ago I got it from my former company and I used it sometimes.Then, one and a half in the past, it began behaving quite strange: it crashed crashed from time to time, and after that it seemed to work no further.Some days ago I took some time to open the scope to have a closer look to all the electrolytic capacitors for a defective one, but on the first look I did not find any.When I turned it on, only the fan was working but after a couple of minutes I heard the clicking sound of the relays inside the device and the normal text appeared on the display.Now it is possible to make measurements with it but in DSO mode the scope still crashes sometimes. In analog mode that seems to be no bigger problem.The strange thing about that is a difference between the timebase of DSO and analog mode: both are incorrect (I checked that by measuring the CAL pin @2kHz/600mV) and both also differ from each other.Does anybody have an idea, what the problem(s) could be?Cheers, ChristophMS72

author: David Hess
author_rank: Super Contributor
timestamp: February 05, 2024, 11:27:58 pm
content: I would start by checking the power supply outputs for voltage and ripple, but chances are the aluminum electrolytic capacitors needs to be replaced.