hybridfree/eevblog-posts huggingface dataset:
Help rebuild filter board - Page 1
Forum section: electronics / repair

author: jamorais
author_rank: Newbie
timestamp: March 30, 2024, 10:39:38 am
content: Hello everyone.I need your expert advice on what i think is a simple matter.I believe i have a 3 phase mains filter board from an industrial rectifier.The thing is very corroded and it seems it have been tampered with before.Now this is what i came up with after tracing.Makes sense?Seems to be only some X2 caps and discharge resistors.X2 between Ls and N are X2 0.47uF 275VX2 between PE and L-N are X2 4.7nF 275VDischarge resistors seem to be 10MohmWhat improvements do you think i could make, if any?

author: jonpaul
author_rank: Super Contributor
timestamp: March 30, 2024, 12:20:27 pm
content: need schem of rectifier and load to comment.Very high transient energy on 3 ph industrial mains bus due to inductive loads.j

author: jamorais
author_rank: Newbie
timestamp: March 31, 2024, 08:35:17 am
content: Thank you jonpaul.I wish i had the schematics for the rectifier.I can tell you that these are rectifiers used for plating lines.Their typical load on the output is around 12VDC - 800A (max 2000A), and about 400VAC - 25A in the input.Hope it helps a little
Help releasing header connector - Page 1
Forum section: electronics / repair

author: Geektronix
author_rank: Contributor
timestamp: January 23, 2023, 07:57:52 pm
content: Can anyone tell me how the header connector (circled in yellow in the attached photo) releases the flexi cable? It's from a Garmin GPS.

author: mariush
author_rank: Super Contributor
timestamp: January 23, 2023, 08:07:18 pm
content: I think you lift up the black bit then pull out the flex strip.

author: wasedadoc
author_rank: Super Contributor
timestamp: January 23, 2023, 08:20:17 pm
content: In most case, lift the brown part. In some it hinges. In all case it is very easy to break it.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 23, 2023, 08:28:21 pm
content: Colors must render differently on my screen. To me this looks like connectors where you lift the pale tan or off white section of the header straight away from the board, it will only move a mm or two. As mentioned all of these are easy to break, but they often require a moderate amount of force to release. I find it easier to lift one end at a time. I also find it easy to damage the flex cable during insertion, so be careful of this step.Best of luck in your explorations.
[SOLVED] Help repairing a defective  HiLo All-11C Programmer - Page 1
Forum section: electronics / repair

author: giovannirat
author_rank: Regular Contributor
timestamp: December 22, 2021, 08:16:50 am
content: I need support regarding a defective HILO All-11C Programmer.Unfortunately I have no User Manual, nor a service manual or schematic.Connected via RS232 the programmer will be recognized by the software (Version 3.10). Also the LED'S and the "YES" switch on the programmer are working as they should.But the hardware test fails partly.TTL test: TTL driver test errorGND test: GND driver test error PIN 1 (I assume other PIN's are also affected, but the test stops here..)VCP test: VCP driver test error PIN 27 (I assume other PIN's are also affected, but the test stops here..)VHH test, VOP test and VOPX driver test are OK.- Does anybody have a documentation available (user manual, service manual, jumper settings on the two internal boards, possible test POD's or test procedures, ....) ?- What is the best proceeding to find the error?Tips and hints are welcome, documentation too.Thank you very much.

author: fzabkar
author_rank: Super Contributor
timestamp: December 22, 2021, 05:52:04 pm
content: This is my go-to site for HILO and Sunshine programmers:http://matthieu.benoit.free.fr/index.htmlNote that some HILO models have Sunshine equivalents.

author: giovannirat
author_rank: Regular Contributor
timestamp: January 05, 2022, 08:17:44 am
content: One step further....I exchanged the U4 PROM on the top board. TTL Test and GND test are now ok. Still VCP test error on PIN 27.During VCP test I measured the correct voltage on PIN 27, so I suspect a problem in reading this voltage.I was wrong. I changed a dead diode on a hybrid VCP board, now everything is working fine.I found a lot of information on Matthieu Benoit site, but still searching for additional information (schematic, calibration procedure, test possibilities, manual, etc..)
Help repairing a motherboard MSI Z77A-G43 - Page 1
Forum section: electronics / repair

author: kyhou
author_rank: Newbie
timestamp: January 17, 2021, 06:59:21 pm
content: Hello there!I have an old PC with an MSI Z77A-G43 motherboard that died recently.After investigating the board I found a MOSFET in the VRM area that was destroyed.I was able to get the number of it - Nikos P0803BD VNE03L20.If I search for this on the net I can't find this exact component. I found a bunch that is similar, but I don't know if could lead to other problems in the future.Can someone help with this situation?ThanksOBS.: sorry about the bad English
Help repairing an IBM Executary 211 - Page 1
Forum section: electronics / repair

author: mercurialization
author_rank: Newbie
timestamp: January 21, 2022, 06:42:28 am
content: Hello,I recently purchased an old IBM Executary (model 211) dictating unit from eBay. I want to use this for tape loops, but it needed a serious cleaning, a new belt, and some oil.I disassembled the entire unit and now, after partially reassembling, I can’t seem to figure out what’s going on with the clutch magnet, or solenoid, arm that allows the playback speed wheel (small) to make contact with the drive wheel (large). When playback is engaged then the solenoid engages and pushes the arm holding the playback speed wheel closer to the drive wheel; albeit, not close enough to make proper contact.Does anyone have any history working on these units? I’ve attached a video, photo, and documents detailing the clutch magnet and other related functions.Image:https://pasteboard.co/7hzgXZdl4Mzb.jpgPartial documentation:https://pasteboard.co/dOi22vRawTIE.jpgVideo:https://youtu.be/h5UFsh5cGM4Full documentation:https://www.docdroid.net/XGHSMHz/ibm-executary-211-schematics-pdf
Help repairing an old toy RC dump truck - Page 1
Forum section: electronics / repair

author: AnthonyC
author_rank: Newbie
timestamp: September 21, 2019, 06:56:47 am
content: Hi,I am hoping that someone will be able to give me some advice on what to try next in the restoration of an old RC dump truck (1980s vintage). I started this as a project to try and advance my electronics knowledge.With both the remote and car powered up nothing works and unfortunately I do not have access to anything that would be able to measure the RF output.Unfortunately the truck does not have any indicator lights to show it has powered up ok.I have probed the circuit as best I can and it seems to be getting power to the chip, but as mentioned above I have no way of measuring the RF output.I have checked the motors and they are all working (steering, tip mechanism and wheel drive).I have cleaned up the battery compartment, desoldered and resoldered, as it was a bit crusty from holding some old batteries.I have replaced all of the electrolytic capacitors, though they all tested fine out of circuit.The main chip is a TA7557P.Let me know of any other info you need.What would people suggest is the next best step?Maybe this is the excuse I need to purchase a scopeThanks in advance for any assistance.

author: ledtester
author_rank: Super Contributor
timestamp: September 21, 2019, 08:49:58 am
content: Do you know what frequency the car operates at? It'll either be 27 Mhz or 49 Mhz.One option is to find another known good controller that operates on the same frequency to troubleshoot your car. Check with your local hobby store to see if they can help you out.Another is to order a new controller and receiver board -- e.g., like:https://www.aliexpress.com/item/33009973632.htmlYet a third option would be to convert the vehicle to use bluetooth and control it from your phone or computer. This will give you a much more robust and reliable communications channel .This kind of conversion has become a very popular diy project, and there are many examples of how to do this on the web -- i.e. search for "convert rc car bluetooth". And there are car control apps available for both Android and IOS, e.g.:https://play.google.com/store/apps/details?id=braulio.calle.bluetoothRCcontroller&hl=en_US

author: AnthonyC
author_rank: Newbie
timestamp: September 21, 2019, 08:54:10 am
content: Ah, great ideas! It is 27 Mhz. I will see if I can find a controller that I can test with.Very tempted by the bluetooth option though! I think I will give that a go.Thanks for your help, it may be a few weeks, but I will let you know how it goes.

author: AnthonyC
author_rank: Newbie
timestamp: October 09, 2019, 05:18:45 am
content: Tried with another controller and no luck.I went with the new controller and receiver board and it works perfectly!My three year old is now having loads of fun shnew toy!Thanks for the tips!
Help repairing EATON DX3000 UPS - Page 1
Forum section: electronics / repair

author: lu5yus
author_rank: Newbie
timestamp: June 13, 2025, 11:45:05 pm
content: Hi, i'm having the next issue with this UPS: battery was not charging, i found out one MOSFET and one IGBT shorted, i replaced them. Now the battery is charging, but when trying to activate AC output, the UPS makes a continuous beep indicating error code 25, wich stands for "fail to start bus". Could anyone suggest me how to proceed? Thank you!P.S: i checked the MOSFET driver, it's a UCC27423, i found out that pins 1 and 8 (enable A and enable B) are shorted. This is a inverted output driver and the only replacement i can find locally it's the UCC27424 wich is non-inverting. I also found the PWM controller, it's a 3845B, and couldn't find any short in that IC. I'm guessing the next step would be to energize the UPS and try to find the PWM signal with and oscilloscope. Do you have any other suggestion? Thank you! Here are some pictures of the IC's location on the board. and the 27423 datasheet.
Help repairing Firebox Electric Firelpace - Page 1
Forum section: electronics / repair

author: unmakingyou
author_rank: Newbie
timestamp: February 10, 2024, 01:36:04 pm
content: Hi thereI am trying to repair an electric fireplace, however I'm new to this topic. I have already checked the thermal fuse and the thermal switch and they both seem to be ok. The fireplace has an "open door" detector, meaning it is supposed to switch off if it detects a window or door is open. I think this is achieved by means of a thermistor that is mounted on its own little board. i have attached an image of the back and front of the thermistor board, and of the main circuit board, and the thermal fuse/switch. the problem is I don't know how to check if the thermistor is ok, I don't have a spec for it and I don't think there is anything on the board that gives me this information?the issue with the electric fire is that it is not turning on at all. the continuity of the plug, the thermal fuse and thermal switch all seem ok, i checked those with a multimeter.any help is greatly appreciated!!
Help repairing GM328A screen - Page 1
Forum section: electronics / repair

author: cristiano.sar
author_rank: Newbie
timestamp: October 24, 2023, 05:31:03 pm
content: I have a GM328A tester that I have broken it's original screen.As a replacement, I bought another screen (1.8 TFT SPI 128*60 v1.1) but it does not worked simply by connecting it's 8 pins the same way as the original screen.Do you have some idea of how I can connect it (what pin of the LCD should go to what pin of the GM328A board)?In the LCD pins are labeled as: LED, SCK, SDA, A0, RESET, CS, GND, VCCAttached is an image of both.Thanks.

author: m k
author_rank: Super Contributor
timestamp: October 30, 2023, 08:04:09 pm
content: Maybe display type is different and not accepted by the driver.
Help repairing HP 4294a Impedance analyzer - Page 1
Forum section: electronics / repair

author: hvontres
author_rank: Contributor
timestamp: January 04, 2023, 07:11:45 am
content: I am currently trying to revive an old agilent 4294 Impedance analyzer. Initial troubleshooting seems to point to a dead A9 floating power supply or a faulty A2 Source amp. Does anybody here have any leads on Internal documentation that could help track down the issue ? I kind of miss the detailed documentation that came with the older HP equipment.Also, does anybody know of sources for spare parts for these units?Thanks for your help,Henry von Tresckow

author: rfengg
author_rank: Regular Contributor
timestamp: January 04, 2023, 02:35:21 pm
content: Hope the attached link to doc helps......file is too large to post here......which parts are you looking for?https://seabaugh.nd.edu/assets/330848/at_man_agilent4294aservicemanual.pdf

author: hvontres
author_rank: Contributor
timestamp: January 04, 2023, 03:56:20 pm
content: Thanks for the link. Unfortunately, I already have that document and unlike the classic HP documents, it only really covers the overall system but has no info for board level troubleshooting.At this point I think I would need the following parts:A9 Floating supplyA59 LCD inverterPossibly also a new A2 source board, but I hope it is just the missing 24V supply that is making it not work.Thanks for your help.
Help repairing Klipsch KDA amplifier power supply and identifying smd component  - Page 1
Forum section: electronics / repair

author: r2digital
author_rank: Newbie
timestamp: April 28, 2024, 11:52:41 am
content: Hello, I Have a klipsch KDA500 amplifier that has a bad power supply. It turns on after about 10 attempts but im barely getting any voltage on the -13 volt rail. I have compared voltages to a working KDA1000 with the same power supply and this is what i got. Picture with the purple line shows where the trace starts at the yellow wire and ends at the negative trace of capacitor 35v 47U capacitor and should be -13-14VDCkda500 power supply {not working properly}right to left4 pinbrown 8.06black 7.93white -0.11gray -0.105 pingreen 30.16blue 3.29green 2.58red/white 3.01red 1.113 pinyellow -.759 <—— this should be -13-15VDClight blue -0.024yellow 13.783 pinblack 165brown -166red -165Kda1000 operating normally4 pinbrown 8.52black 8.92white -0.003gray - 0.0035 pingreen 32blue 3.33green 2.6red/white 3.05red 1.13 pinyellow -13.7light blue 0yellow 13.83 pinblack 157.5brown -157.8red -157.855bz<—- need help identifying what this is as it is not giving me proper voltagesthese are the measurements from the working power supply on the 55BZ smd component1 -18.22 -18.23 -5.834 -18.715 -18.716 -18.71The measurements from the non working power supply 55BZ chip1 0.3802 0.3803 -204 0.4205 0.4006 -20

author: fzabkar
author_rank: Super Contributor
timestamp: April 28, 2024, 04:34:37 pm
content: "55BZ " looks like a MOSFET.Edit:http://markingcodes.com/search/c/55bYour readings don't quite match the pinout, but ...FDC655BN, Fairchild, PowerTrench MOSFET, 30V, 6.3A, N-ch, marking 55B, SSOT-6:https://datasheet.octopart.com/FDC655BN.-Fairchild-Semiconductor-datasheet-8322017.pdfhttps://ae01.alicdn.com/kf/S35c02a7f79e54cceb3c7f6a349c5a23b1.jpg(photo)

author: r2digital
author_rank: Newbie
timestamp: April 28, 2024, 07:50:46 pm
content: this is great, thank you! I do believe FDC655BN is the part
Help Repairing SurgiTel Micro LED Headlamp - Page 1
Forum section: electronics / repair

author: SuperGova
author_rank: Newbie
timestamp: July 07, 2020, 07:41:27 pm
content: My wife is a dentist, and relies upon a bright uniform headlamp to look into people's mouths. I've found that the technology related to surgical/medical/dental headlamps - despite being extremely mission critical, and outrageously expensive (high profit margin) is not very "state of the art", or even well designed. I learned this by attending a dental tradeshow and speaking with the reps, and owners of these headlamp companies. There are a number of companies - and SurgiTel is actually one of the best - but still has many issues.My wife has a SurgiTel Micro LED Headlamp. This thing has crapped out several times - most often because the lack of adequate strain relief on the 3.5mm phono jack used for connection to the power supply. (I had applied an encapsulation of hot glue - to provide some strain relief - but have remove it all for diagnostics) Additionally the power supply has also gone bad, and now it appears that the LED has simply burnt out. (Not a great deal of heatsinking is incorporated into their design.)Does anyone know this type of LED?I'd like to simply reverse engineer the whole thing and build a more robust design. Maybe someone here can help.Do you have a good LED dimmer schematic or recommendations?Thankshttps://www.surgitel.com/headlights/surgitel-micro
Help Repairing Tridonic LED Driver - Page 1
Forum section: electronics / repair

author: hugo_g
author_rank: Newbie
timestamp: April 23, 2021, 04:29:37 am
content: Hi,I was hoping to get some guidance on repairing an LED Driver which failed.I discovered no damage to any components with a visual check, or no bad solder joints.With some simple continuity tests I determined that F1, which I assume is a flameproof/fuseable resistor, failed. There was no continuity, but working drivers did have continuity.I also assumed it as a Vishay PR02 4R7 resistor (that a 2W one). Based on the resistor colour, the wire diameter and general appearance.So I replaced the part, connected it up and poof!!The same part blew. TBH I didn't have high hopes, I expected this failed as something else downstream had failed and this was a safety feature.Anyway I'm out of ideas. Having working drivers I compared continuity, if something had failed open or closed, and so far following the tracks and comparing values with the DMM everything looks just the same as the working one.I wanted to see if anyone has some ideas. This is not the kind of thing I would put back in service, but I'm treating this as a learning exercise.https://www.tridonic.com/com/en/products/led-driver-lca-15w-180-350ma-flexc-ph-c-sr-adv.aspSome Tech Spec's: Driver LCA 15W 180-350mA flexC PH-C SR ADVProduct descriptionDimmable constant current LED Driver (SELV)Independent LED Driver with cable clampsDimmable via leading edge and trailing edge phase dimmersDimming range 5 to 100 % (depending on dimmer)For luminaires of protection class I and protection class IIFor luminaires with M and MM as per EN 60598, VDE 0710 and VDE 0711Temperature protection as per EN 61347-2-13 C5eSelectable output current between 180, 250 and 350 mAMax. output power 15 WUp to 81 % efficiencyNominal lifetime up to 50,000 h5 years guaranteeHousing propertiesCasing: polycarbonate, whiteType of protection IP20InterfacesTerminal blocks: 0° screw terminalsFunctionsOverload protectionShort-circuit protectionNo-load protectionOvertemperature protectionBurst protection voltage 1 kVSurge protection voltage 1 kV (L to N)Surge protection voltage 2 kV (L/N to earth)

author: james_s
author_rank: Super Contributor
timestamp: April 23, 2021, 05:24:25 am
content: That's exactly what I'd expect to happen, fuses very rarely blow on their own. Test all of the semiconductors, one or more of them is shorted. It's probably not really worth the effort but it could be a fun educational project.
Help repairing Voltrex SMPSU for HP41501A - Page 1
Forum section: electronics / repair

author: chilternview
author_rank: Frequent Contributor
timestamp: May 25, 2023, 02:43:46 pm
content: I've a HP41501A which has a dead power supply... the PSU is a self-contained unit, manufactured by Voltrx Corp of Japan. I've not been able to find a schematic or even any details of this unit, marked 'FPS2 D2161' and dated 1993-9.Checking the power route from the AC socket, the bridge rectifier is OK and providing +250v DC. There is a Harris HV3-2405E-5 taking mains and providing +15v to a IR2110 mosfet driver. But the inputs to this are from a vertical board (see pic) which is potted and appears to have a single IC in it, plus a few SMD components. And those gate signals are sitting at 0v all the time.The black potted thing is marked 'Voltrx CAP-3001C' and I did try swapping it for another from another board I have, but that made no difference. I've also replaced all the electrolytics, so I'm a bit stumped.If anyone's any knowledge of this PSU, and possible fixes, I'd be really grateful!!!

author: chilternview
author_rank: Frequent Contributor
timestamp: May 25, 2023, 06:23:37 pm
content: When I posted the above today I really thought I had little hope of fixing the problem. With no documentation or info on the power supply, it was not looking good. It was sold as 'not working' on eBay and so was cheap, as was the 41501A that I had also bought cheap because it had no power supply. The odds of finding two allegedly broken parts of a unit that could be fixed and put together to make a working one (which sell for $5000 or so) was remote.The power supply consists of 4 boards: the base unit in the pic above, a top unit and two interconnecting PCBs. One of the interconnecting PCBs, visible at the top of the picture below, runs power and a few control signals to the other. I had not disconnected it before as it was quite firmly attached to the top board. But today it came loose as I was trying to put the thing back together again. I noticed that it could go either way round! The connectors each end of it were identical. But the silk screen of the two PCBs gave the plug/socket numbers, which would, I thought, indicate the correct connection. Which was the opposite way round to what it had been all along...Putting it back together and plugging it in and switching on, hoping it would not emit smoke... the fans started working! And when fitted into the 41501A, that powered up. And so connecting the 4155B and 41501A together I now get the HPSMU and PGU's recognised... how good is that.Moreal of the story... check *everything* even the obvious.
Help reparing Sony WH-1000XM3 - Page 1
Forum section: electronics / repair

author: DavrosTheDalek
author_rank: Newbie
timestamp: March 28, 2023, 01:28:24 am
content: Hi all,I need some help repairing my Sony headphones. Symptoms: Doesn't charge when USB is plugged in. USB cable also not recognized (would normally switch off when plugged in). Charger light does not light up.My suspicion is that a chip on the USB connector board has given up the ghost. I see the 5V USB power next to it, but I don't see any voltage > 0.5V on the connector to the rest of the headphone. Problem is, I am not sure what chip that is.It's a 2x2 mm square, some contacts below the IC, can't tell how many. Seems to be labeled 04/A (or 047a) and 9M92. I don't recognize the logo, if it's actually a logo and not just the pin1 indicatorI'll attach a picture here.The resistor below it is 100k, the one to the right is 5k. The soldering pad above it has 5V USB, the one to the right is GND. My suspicion is that the area to the lower left should get connected to the 5V (or should have some reduced voltage, but I doubt it, there is a li-ion in the system with 3.7V).Any ideas?Thank you all in advance!

author: DavrosTheDalek
author_rank: Newbie
timestamp: March 29, 2023, 11:25:58 pm
content: Ok, found out some stuff.I mechanically remove the IC. It's a 2x2mm BGA. Most of the connections go to the connector side V_BUS. One goes to GND, 2 go to V_out and one goes to V_ouit via a 100kOhm resistor.Is that some reverse polarity/current protection with some clever MOSFET hookup? Or some ESD protection or over voltage protection?I tried just bridging V_BUS to V_OUT, and the headphones charge again.

author: GrégoryP
author_rank: Newbie
timestamp: March 28, 2025, 04:25:09 pm
content: Hi Davros,Got the same issue.I could figure out the 047A IC ishttps://fscdn.rohm.com/en/products/databook/datasheet/ic/power/battery_management/bd6047agul-e.pdfI would advice to change it and not simply bypass it as it is indeed protecting the rest of the electronics from surges.And if you can not solder 3x3 BGA IC, you may want to order a new board:https://fr.aliexpress.com/item/1005007026982970.htmlI did go for the 2nd solution and my headphone now charges perfectly.Cheers,Grégory

author: tom66
author_rank: Super Contributor
timestamp: March 28, 2025, 04:34:41 pm
content: My guess is the device is there to protect against bad USB-C and USB power chargers that can inadvertently switch to higher voltages, since the headphone only wants to charge from 5V supply. Some older USB chargers for phones would have high voltage charging activated by using a sequence of pulses on the D+/- which can be inadvertently generated by intermittent connections or external noise sources.If you are confident that will not be an issue, for instance, you only use 5V supply or a good quality adapter, bypassing the IC is probably fine.
Help - Replacement “Light Diffusers” for LCD TV - Page 1
Forum section: electronics / repair

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: October 11, 2019, 03:17:46 am
content: I did a repair on a 60" led Samsung TV which went fine, but, I left the diffusers (the parts between the thick plastic and the LCD panel) rolled up in this period of 2 weeks waiting on parts. Well at somepoint something must have smoodged it to leave some open spots on them. It now has serious smearing where the light is shining through.Does anyone know what this material is and where I can order a replacement or the raw stock myself? Thanks!
Help replacing sheathed banana jacks HMP4040 - Page 1
Forum section: electronics / repair

author: D2236
author_rank: Regular Contributor
timestamp: April 22, 2025, 01:37:13 am
content: We have some broken jacks on a R&S HMP4040, from someone dropping the unit. Hopefully, someone knows the brand type used in these PSU units, so we can replace it with the same type.

author: coppercone2
author_rank: Super Contributor
timestamp: April 22, 2025, 01:48:21 am
content: make it gangster and put binding posts on itI don't like R&S decision to make it recessed. I never understood it if its under 1kVI have one and I find it really impractical.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2025, 02:47:07 am
content: like this ?https://www.mouser.ch/ProductDetail/Shin-Chin/R1-24B-02-R?qs=7EBvPakHacWtuDIdwAOWOg%3D%3Dhttps://www.mouser.ch/ProductDetail/Shin-Chin/R1-24B-02-B?qs=T3oQrply3y99YtFxyT00NA%3D%3Dfor the blue ?all colors on aliflat teminalhttps://www.aliexpress.com/item/1005008533888340.html?https://www.aliexpress.com/item/32684201221.html?screwshttps://www.aliexpress.com/item/1005006124262851.html?but we dont see the back of the plugs, there is some pcb mount too

author: D2236
author_rank: Regular Contributor
timestamp: April 22, 2025, 02:57:14 am
content: Although similar parts are available from various sources, we would prefer to replace it with the same manufacturer type used by R&S.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 22, 2025, 10:06:45 am
content: well no pun, ask R&S where they come from ? or dismantle / remove one to check markings on itdo you need it fast or wait until ....

author: odium
author_rank: Contributor
timestamp: April 22, 2025, 02:12:58 pm
content: Guessing by the looks maybe they are HIRSCHMANN brand.but better disassemble and take a look at it !cheers.

author: D2236
author_rank: Regular Contributor
timestamp: April 22, 2025, 04:46:11 pm
content: The broken jacks are still functioning, so no immediate rush. It is just one of the things on the to-do list. I would expect R&S to use some local manufacturer, so Hirschmann is one possibility.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: April 22, 2025, 05:30:59 pm
content: Hi D2236,my guess is "Stäubli":https://www.buerklin.com/de/p/staeubli-electrical-connectors/laborsteckverbinder/23-3000-22/22F262/Pick the variant with hex-nuts if you don't own the special tool for the round nuts.Good luck

author: D2236
author_rank: Regular Contributor
timestamp: April 22, 2025, 06:04:24 pm
content: I will definitely check out all of these after opening the unit to verify mounting and fit. Another one that comes to mind is, Mueller Electric Co. Thanks for all the suggestions.
Help requested identifying toaster timer / controller chip - Page 1
Forum section: electronics / repair

author: winelight
author_rank: Newbie
timestamp: December 15, 2020, 03:14:10 pm
content: Here is the schematic for a toaster I am trying to repair. The chip is clearly Functionally similar to the Pericom PT8A2511 (and the many other similar chips sold under different numbers), however, the pinout is different.The chip is unmarked and I just don't understand why this one toaster should be using a chip that has a pinout different from the "standard" toaster controller.Does anyone have any ideas on what it might be please? I have searched for toaster controller chips but not turned up anything that matches this.The schematic is laid out similar to the one in the Pericom datasheet so both the similarities and differences should be apparent to anyone familiar with that.

author: fzabkar
author_rank: Super Contributor
timestamp: December 15, 2020, 06:07:12 pm
content: The Vdd and Vss pins are consistent with a PIC microcontroller.https://ww1.microchip.com/downloads/en/DeviceDoc/41190G.pdf

author: winelight
author_rank: Newbie
timestamp: December 15, 2020, 07:28:26 pm
content: That would explain the mystery. Makes perfect sense. Thank you.
Help Required - Master Electronics trail camera over voltage problem - Page 1
Forum section: electronics / repair

author: danon.spy
author_rank: Newbie
timestamp: June 27, 2017, 02:32:05 pm
content: Hi everyone, first of all, I'm wishing you all have a good day.I have this trail camera and it has power problem and now I cannot make it works anymore.In last few days, in a hurry, I had powered it with 9V by accident, normally it would take only 6V max. But I was carelessly and its consequence is the camera not working anymore. I know something had been fried, but I have no ideas which ones to replace. My knowledge about electronics is only about re-soldering and testing simply board. I have tried to trace the power but... it's a maze to mePlease, if anyone see this thread and know how to fix it, or know who can fix it, do not be hesitate to comment. As to be honest, this camera helps me a lot. And my limited budget allows me trying to fix it by myself. I don't know if anyone can fix it under $50 as I bought this ones $129. I live in Belmore, Sydney NSW.This is the inside of the trail camera:Thanks to all of you for reading this...

author: danon.spy
author_rank: Newbie
timestamp: January 18, 2018, 01:36:10 pm
content: Please, anyone help me?

author: Gyro
author_rank: Super Contributor
timestamp: May 19, 2020, 09:16:44 pm
content: Quote from: Nobility on May 19, 2020, 09:06:55 pmSo why resurrect a thread that's over 2 years old to say that?!It doesn't seem very noble to me.
Help required with P/S issue - Page 1
Forum section: electronics / repair

author: digsys
author_rank: Unknown
timestamp: July 04, 2019, 02:15:04 am
content: Been called in to find the problem with intermittent false alarms in a security installation. I think I've tracked it down to this P/Supply, but not sure.I'm suspecting a wrong value of R3, but just need a 2nd opinion ... if not, any other possibilities?

author: Mr.B
author_rank: Unknown
timestamp: July 04, 2019, 02:27:48 am
content: Nah...Looks to me to be that dry joint on the collector of Q1.

author: Mr.B
author_rank: Unknown
timestamp: July 04, 2019, 06:57:02 am
content: While the apparent presented problem is neither LED lighting related, nor SMPS, perhaps someone can PM @Treez for his input.I hope he thanks me for mentioning him...

author: digsys
author_rank: Unknown
timestamp: July 04, 2019, 07:24:32 am
content: Poke the bear why don't you !! :-)

author: Mr.B
author_rank: Unknown
timestamp: July 04, 2019, 07:32:53 am
content: Who is it that is pokingbeersbears?
Help Rohde & Schwarz CMU200 Display Issue - Page 1
Forum section: electronics / repair

author: jessejgm
author_rank: Newbie
timestamp: April 09, 2024, 10:46:46 pm
content: Goodnight. I'm wanting to buy this cmu200. But I'm in doubt because of the problem with the display turning orange. And there is no clarity.Could there be a problem with the screen? In the Capes?It is worth it?I'm a beginner in the area.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 09, 2024, 11:16:34 pm
content: dont double or triple post

author: Halcyon
author_rank: Unknown
timestamp: April 09, 2024, 11:17:09 pm
content: Triplicate post.
Help searching compatible LiPo battery for old DAP - Page 1
Forum section: electronics / repair

author: ThunderZed
author_rank: Regular Contributor
timestamp: October 29, 2021, 06:40:41 pm
content: I've got an old Cowon iAudio U3 carrying a 3.7V lipo battery with this codes (se attachment):Code:pr-0424586a1002465p5123602adThis battery lasted about 20 hours at its beginnings while now it lasts only 4 but I need 10 hours at least so I've to change it.We know its dimensions (58mm x 24mm x 4mm) and it's voltage (3.7).My main trouble is to find a site where to buy from because I usually buy from aliexpress but the most part of these batteries are sold without the tracking and I know for sure it'd be missed (= stolen, because I buy from Italy!) during its journey. Eg.https://www.aliexpress.com/item/32896640980.html58*25*3.5 - 470mha - 4.55eurAnyway I guess it wouldn't be good because it has 3 wires while mine only 2, would it?Another big problem is the dimensions code to search, I mean a 58*24*4 battery's code could be found as: 582404, 580424 245804 240458 045824 042458 + other 6 combinations with "40" instead of "04".Can you help me please?

author: m3vuv
author_rank: Super Contributor
timestamp: October 30, 2021, 07:22:15 pm
content: i have a dead pack for a baofeng uv-5 here opened up,there are 2 flat rectangular cells,each measures 45mm long ,about 10mm deep by about 33mm wide,dont know if that helps,if so get one from fleabay and open it up,one cell may do the job and keep a spare.

author: ThunderZed
author_rank: Regular Contributor
timestamp: March 22, 2022, 07:30:21 pm
content: I've found out these 2 lipo batteries:-ICP402050PR- 2 wires - "Safety Circuit: Yes"-ICP622540PMT- 3 wires - "Safety Circuit: Yeswith NTC"Why have they got a different wires number? What does "with NTC" mean?
Help, Siglent SDG1032X display is offset to the left  - Page 1
Forum section: electronics / repair

author: dddarrel
author_rank: Newbie
timestamp: January 13, 2024, 08:01:17 pm
content: I recently bought a used Siglent SDG1032X. It works perfectly but the display image is offset to the left by enough that the text of the left most option button and part of the text on the main image is obscured making it difficult to read. Does anyone know if there is an adjustment to center the image? Most displays have one but I can't find any documentation on how to do it on the SDG1032X.Thanks.

author: uski
author_rank: Frequent Contributor
timestamp: January 15, 2024, 07:21:05 am
content: Can you post a picture of the issue and are you sure it is not a mechanical issue?Since this uses an LCD screen, it is unlikely that it has a horizontal position adjustment like on old CRT screens, and it is also unlikely that an electrical fault will cause the display to actually shift. Take a look first for a mechanical shfting

author: dddarrel
author_rank: Newbie
timestamp: January 15, 2024, 02:55:58 pm
content: Thanks for the input. I don't want to open the unit quite yet since I can return it for a refund. I was hoping there was a software way of adjusting the image position. I've attached a photo of the shifted screen. The shift is most obvious for the left most menu item on the bottom of the screen where the "frequency/period" is obscured.

author: voltsandjolts
author_rank: Unknown
timestamp: January 15, 2024, 04:17:35 pm
content: Return it.

author: dddarrel
author_rank: Newbie
timestamp: January 18, 2024, 01:28:12 am
content: Thanks for the inputs.
Help soldering Molex LA75 type FPCs - Page 1
Forum section: electronics / repair

author: 0xPIT
author_rank: Regular Contributor
timestamp: March 22, 2024, 03:47:03 pm
content: Hi,I seem to fail soldering Molex LA75 type FPCs to a PCB.While I have no problems with some other fine pitch connectors, but I'm at a loss why I just can't get those connectors to actually stick to the solder.It looks like it's too little sonder, so that the contacts are slightly too far away, but the tiny pads don't seem to hold more solder. Also, I can't press on the connector when it's hot as it will dent the plastic.So far, I've tried 3 types of solder (Regular SnPb, 183° and 138°) and different fluxes without success.Thanks for any advice or video you can point me to (I can't even find a YT video of someone soldering this type of connector)pithttps://www.content.molex.com/dxdam/literature/987651-1941.pdf

author: Jwillis
author_rank: Super Contributor
timestamp: March 22, 2024, 06:21:00 pm
content: Sounds like you are applying heat to the top of the connector and the heat is not reaching the metal before the plastic melts. Apply the hot air to the other side of the PCB.This limits the heat to the plastic of the connector. The PCB can handle more heat than direct heat to the connector.
Help solve tangled transformer freq contradiction against induction heating - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 12, 2023, 03:13:12 am
content: As a transformer frequency get higher, inside its induction get more efficient i.e. less loss:1. Hysteresis loss = η * Bmax^n * f * V2. Eddy current lossFirst, it seems that losses increases with increase in frequency...But the above equations are valid when max flux density Bmax remains constant.The gist is that in Hysteria loss when increasing the frequency flux density does not remain constant, it actually decreases with increase in frequency, asV = 4.44 . Bmax . A . f . TpThe gist is that in Edd current loss is it's independent of the frequency as it gets canceled in substitutionNow how is it on Induction heating, as it's read more, the more contradiction is to abovehttps://en.wikipedia.org/wiki/Induction_heatingPlease help unravel this, thanks much
Help Source Output Power Module - Page 1
Forum section: electronics / repair

author: Geworthomd
author_rank: Newbie
timestamp: January 16, 2024, 07:14:10 pm
content: :-// :-//]:-// :-//Gentlemen,May I ask for your help. I trying to source these for a project on an older piece of audio that is being repaired for me but not by me. I don’t know much. If your questions are technical I will have to back and ask first so please be a bit patient with my limited knowledge. This isn’t my profession. If you can help then I would respectfully appreciate it.

author: Swake
author_rank: Frequent Contributor
timestamp: January 18, 2024, 12:56:08 pm
content: Hi,It is not mentioned what electronic component exactly you are sourcing. From your text is seems that you are looking something that has to do with a power supply with 3 output channels. Given the 500 Volt DC for the first channel I suspect this is about an audio device with tubes.If this is indeed about a repair, there should be a power supply already in the device. It should be possible to repair that power supply. And this is likely also the easy route.Sourcing a power supply with the listed requirements is not that difficult, although one with an appropriate 500 V channel might be a bit more difficult to find as not very common these days.Could you confirm a power supply with the 3 specified channels is what you need? Or 3 separate power supplies which is the same. Can the two 9 to 11 Volt channels be combined or is a galvanic isolation required?This said, the person dealing with the repair should be able to source the power supply too as there is nothing voodoo about that.
Help spec input JFET replacement? (DC drift problem) - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: October 26, 2020, 08:55:09 pm
content: Hi all-Please look over my shoulder here, I don't spec replacement JFETs every day.I've got two of these amplifiers; one works fine. The other also works but has excessive DC drift and offset. My initial assumption is trouble in the input diff pair, possibly degraded silicon as these are about fifty years old.The amp is modular so there's an audio input card I can swap between chassis. The symptom follows one of these cards, and both chassis are working well (with the 'good' card in place).Offset when cold is -150mV and at 20 minutes it is +700mV. The good card, on the other hand, is nearly perfect (~1mV DCO after 20 mins).I can't find any info on the ITS30874 N Channel JFETs. Rails from the main chassis are +/-28V regulated and verified good. I'll post more as I dig deeper but I suspect I'm gonna need a new JFET somewhere in the input stage.Thanks...

author: cvanc
author_rank: Frequent Contributor
timestamp: October 26, 2020, 08:55:51 pm
content: more pix...

author: David Hess
author_rank: Super Contributor
timestamp: October 26, 2020, 11:29:54 pm
content: Oh, that circuit.The modern parts you are looking for are the LSK489 and LSJ689, but I would double check that there is not some other fault before replacing the JFETs.Check out this application note which discusses the LSJ689 dual p-channel JFET and that amplifier topology:http://www.linearsystems.com/lsdata/appnotes/LSJ689_P-Channel%20Dual%20JFETs.pdf

author: Kleinstein
author_rank: Super Contributor
timestamp: October 27, 2020, 08:40:04 am
content: The offset and drift depends a lot on the matching of the jfets, not so much the actual fet type.There are 2 relatively independent parts: the simple buffer at the inverting input and the main difference amplifier, both can contribute to the offset and drift. The difference stage has 2 trimmers (IM balance and DC0) that should effect the offset and drift - so if lucky one would only need to adjust the settings and not need new parts.

author: cvanc
author_rank: Frequent Contributor
timestamp: November 16, 2020, 12:40:37 pm
content: Thank you both; replacing the upper JFET pair with LSK489 solved the problem. All good now.
HELP: Stereo Separation Problem on 80s Boombox - Page 1
Forum section: electronics / repair

author: RiRaRi
author_rank: Regular Contributor
timestamp: March 14, 2025, 05:29:44 pm
content: Hello. I just repaired few boomboxes from 80s and two of them have similar problem. I made a video of first oneplease check it out. Stereo does not separate until i turn it on and off several times. I cleaned the switch and problem is not in switch. As can be seen, switch is closed and stereo works but as i change station and return to it, stereo is not working again. It does not turn on as station is tuned. After you see the video, everything will be clear. All e-caps measured good. Anyone had similar issue? What could be the problem? Should i re-align the radio or separation pot?

author: vidarr
author_rank: Frequent Contributor
timestamp: March 14, 2025, 07:37:59 pm
content: I am working on something similar now --80s boom box. The stereo for the radio is hit or miss. I can tune it sometimes and get the stereo, but other times it doesn't want to go stereo. I checked the stereo with the cassette player, mic, aux inputs and everything seems fine. It is just the radio that goes in and out of stereo. This is not a surprise, because this happened to me with other radios in the 80s.Maybe someone knows how to better tune the radio and give some advice.

author: wasedadoc
author_rank: Super Contributor
timestamp: March 14, 2025, 08:10:55 pm
content: It is usual that a stereo FM receiver does not go into stereo mode unless the signal strength is relatively strong. There will be variations in signal strength due various reasons and those could account for the behaviour you are experiencing.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: March 14, 2025, 08:35:33 pm
content: There should be a point somewhere where you could probe the 19 Khz pilot tone, necessary for stereo demodulating.Have you identified the demodulator IC? (Or discrete circuit area)

author: RiRaRi
author_rank: Regular Contributor
timestamp: March 17, 2025, 03:57:26 pm
content: Hello everyone. I fixed the issue. I tuned the radio to strong FM station and then cleaned and moved this 10K ohm pot which is used for FM stereo separation. At one point stereo started to work perfectly. But i have question: Is it acceptable to do it this way instead of following the service manual, which uses a signal generator and oscilloscope for precise 19kHz measurement?

author: Manolo Mos
author_rank: Contributor
timestamp: March 17, 2025, 10:42:40 pm
content: This potentiometer must be 76khz PLL adjust. If you find a good adjust point and it works, perfect so. The Sony ST343 and others has the same LA3361 stereo--mpx demodulator, and I think the adjust method is to put to ground a pin, and then to adjust the frecuency to 76khz. 76khz is 19khz x 4 as you can see.

author: UnijunctionTransistor
author_rank: Frequent Contributor
timestamp: March 18, 2025, 08:18:23 pm
content: Those open frame carbon film trimmers tend to drift, quite a lot.It is perfectly fine for you to have tweaked it. I don't think the boom box will explode.Well not unless you play some loud Kayne West music.
Help Tektronix 2467B issue - Page 1
Forum section: electronics / repair

author: GasGas
author_rank: Contributor
timestamp: May 10, 2019, 03:32:58 pm
content: Good Morning.Since yesterday my only scope, the TEK 2467B began to present defect. Soon in the first minutes of operation everything works well, then begins to present the defect as it can be seen in the video. I realized that there is a large voltage swing in the resistors R2101 and R2102 when the defect manifests itself. The electrolytic capacitors of the source were all changed 2 years ago, as well as the electrolytic capacitors of the A5 plate that usually leak. I am not an engineer, I am a repairman of Tv, please someone can help me? I am in Brazil, here there is no chance to buy another plate or send for repair.I thank you from the heart who can help me.https://www.dropbox.com/s/agct84zdz60z3lk/MOV00192.AVI?dl=0

author: henas
author_rank: Contributor
timestamp: May 13, 2019, 01:41:53 pm
content: If you turn on the readout and horizontal cursor, does it shake together with the waveform?