hybridfree/eevblog-posts huggingface dataset:
Desoldering/Soldering plastic membrane push buttons - Page 1
Forum section: electronics / repair

author: sdancer75
author_rank: Frequent Contributor
timestamp: January 04, 2021, 10:51:54 am
content: Hi, how to desolder and solder a plastic SMD membrane push button without destroying i.e using a how airflow station? It concerns a double-sided PCB of a TV remote control.Regards,

author: Psi
author_rank: Super Contributor
timestamp: January 04, 2021, 11:08:30 am
content: For well known switch brands it's usually a non-issue. Just hot air them as you would any component.For your cheaper china/aliexpress brand buttons you DO have to be careful. Keep the temp under control to prevent the plastic case melting.I would set the hotair to maybe 330C and take more time than normal. Start from a good distance away like 6cm. Moving in slowly and bring the part up to solder temp without any overshoot. Maybe 1cm closer every 20seconds.The problem happens when being too impatient and trying to hurry it by moving closer and then you overshoot the temp and it meltsThankfully the cheap aliexpress switches are usually a few $ for 10 or 100 so you have spares

author: sdancer75
author_rank: Frequent Contributor
timestamp: January 04, 2021, 11:24:07 am
content: Quote from: Psi on January 04, 2021, 11:08:30 amThanks !!!Can you suggest me some well-known brands? I buy usually from TME.euBest Regards,

author: Psi
author_rank: Super Contributor
timestamp: January 04, 2021, 11:25:14 am
content: i never have any melting issues soldering Panasonic smt switches

author: Psi
author_rank: Super Contributor
timestamp: January 04, 2021, 11:32:29 am
content: If you're new to hotair soldering one other thing to be careful about is the position of the hot air tip.Because it's all happening at an angle it's easy to think you are pointing hot air directly at the part but you're actually pointing it over the top.Then you come in closer and closer (too close) and then the hot air moves onto the part and it overheats.I recommend moving the hot air around the part in a circle, and keep paying attention to where you're actually putting hot air, its not always where you think.
[Solved] Determine the value of the missing components - Page 1
Forum section: electronics / repair

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 08:57:21 pm
content: Any ideas on how to determine the value of the missing components values without removing the other components form a different section (the PCB has four identical sections that control motors.FatMexican

author: wraper
author_rank: Unknown
timestamp: May 14, 2024, 09:05:01 pm
content: It's obvious that PCB has exactly the same components mirrored on opposite sides (4 copies of the same circuit). Desolder and measure.

author: MathWizard
author_rank: Super Contributor
timestamp: May 14, 2024, 09:08:26 pm
content: Have you looked up any of the chip's? You might find some datasheet with example circuits, that are the same or similar to your's.Where are the missing components, what happened ?

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 09:13:05 pm
content: I Email the manufacturer waiting for the replay; hoping to avoid more disordering if possible.

author: fzabkar
author_rank: Super Contributor
timestamp: May 14, 2024, 09:13:35 pm
content: Could the EEW part be a dual MOSFET?https://www.vishay.com/docs/64832/sia517dj.pdf

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 09:14:13 pm
content: I was removing some connectors and was careless.

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 09:15:43 pm
content: Quote from: fzabkar on May 14, 2024, 09:13:35 pmThe missing components are capacitor and a resister.

author: fzabkar
author_rank: Super Contributor
timestamp: May 14, 2024, 10:40:33 pm
content: Quote from: FatMexican on May 14, 2024, 09:15:43 pmYes, I know. I was thinking that tracing the circuit in that area could enlighten you as to the functions of these components. For example, gate resistors would be of the order of 100 ohms.

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 10:43:29 pm
content: That is the website for the parthttps://betafpv.com/products/f4-1s-5a-aio-brushless-flight-controller-elrs-2-4gThanks for all the help.

author: wraper
author_rank: Unknown
timestamp: May 14, 2024, 10:51:23 pm
content: And what's the problem with desoldering 2 components when you need to solder the board anyway?

author: FatMexican
author_rank: Contributor
timestamp: May 14, 2024, 10:53:28 pm
content: Quote from: wraper on May 14, 2024, 10:51:23 pmNo problem I guess, just an academic exercise.FatMexican

author: FatMexican
author_rank: Contributor
timestamp: May 16, 2024, 07:00:30 pm
content: The manufacturer send me the correct values.
Dewalt dc011 portable radio - Page 1
Forum section: electronics / repair

author: Hornnumb2
author_rank: Regular Contributor
timestamp: September 21, 2024, 12:18:01 am
content: I use this when working in the garage, it doesn’t keep memory anymore. That usually saved on a chip these days right, what would I be looking for when I take it apart? Thanks Michael

author: Kim Christensen
author_rank: Super Contributor
timestamp: September 21, 2024, 02:22:25 am
content: Look for a dead battery, dead supercap, or serial eeprom IC like 24c256, etc.

author: RoGeorge
author_rank: Super Contributor
timestamp: September 22, 2024, 06:12:23 am
content: There are AA backup batteries, accessible from the outside, for clock and probably to keep the other saved parameters, too. Maybe those batteries are dead. Have you checked them?Repair DeWalt Radio Part 1 of 2ToddFunhttps://youtu.be/slENweYSTgEhttps://youtu.be/Y31GA50q7Og
Dewalt DCR025 Rotary Encoder ID - Page 1
Forum section: electronics / repair

author: Thebighat99
author_rank: Newbie
timestamp: January 07, 2024, 03:53:44 pm
content: I found this Dewalt boom box\ battery charger on side of the road as usual anything with a cord on it I have to pick it up and take it apart.It needs a new push switch rotary encoder. I was going to rebuild it but one of the plates is broken. It’s for turning on and adjusting the volume.Why are these not marked with some kind of identifier.if some one could let me know what I need to replace this I would appreciate it. The whole board is $50 and up.Thanks

author: fzabkar
author_rank: Super Contributor
timestamp: January 07, 2024, 09:10:05 pm
content: Would something like this work?https://www.aliexpress.com/item/32809326511.html

author: Koray
author_rank: Regular Contributor
timestamp: January 07, 2024, 09:41:13 pm
content: This one seems more like it:https://www.aliexpress.com/item/32980101073.html
Dexela/VAREX/PerkinElmer 2315 CMOS X-ray Detector Repair - Page 1
Forum section: electronics / repair

author: xmjacky
author_rank: Contributor
timestamp: October 14, 2022, 10:11:19 am
content: I have a Dexela 2315 CMOS X-ray Detector, which works normally. Unfortunately, some of the glue between the internal CMOS image sensor and the Fibre Optic Faceplate (FOP) has come off, causing some shadows to be seen at low brightness, as shown in the picture. Does anyone know what kind of glue is used for fixing by the original factory, and whether UV glue can be used for fixing?thank you
DG190 Analog Switch IC - Page 1
Forum section: electronics / repair

author: Insatman
author_rank: Frequent Contributor
timestamp: December 13, 2021, 06:49:53 am
content: Recently I realized that this obsolete IC (DG190) is selling on Ebay for as much as $45 or more. I am considering making a small plug in replacement board based on more modern surface mount parts. Is there anyone here looking for these parts as well?
DG5101 - Page 1
Forum section: electronics / repair

author: Stampsm
author_rank: Newbie
timestamp: April 24, 2025, 05:41:04 am
content: Hello so I recently got a DG5101 and the self test is giving me an error for the FRAM self test. What is this and should I send it back?

author: coromonadalix
author_rank: Super Contributor
timestamp: April 24, 2025, 07:07:43 am
content: if under warranty return it, have you checked or asked Rigol, any FW updates who could address this problem ?

author: Stampsm
author_rank: Newbie
timestamp: April 24, 2025, 11:57:59 am
content: Definitely not under warranty and bought used for a fraction of the new price. The fw version looks like it is several versions, possibly close to a decade old, but when I looked up updates the links wouldn't work on the rigol website.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 24, 2025, 05:30:28 pm
content: woah many Rigol dg5000 dead links, this one is workingdg5000 series FWhttps://pyeu.shkhxxkj.com/products/waveform-generators-dg5000-dg5101.htmlhttps://pyeu.shkhxxkj.com/item-downfile.html?file=https%3A%2F%2Feu.rigol.com%2Feu%2FImages%2FDG5000DSPupdate_tcm30-4030.zip
Diagnosing faults in Milwaukee batteries - Page 1
Forum section: electronics / repair

author: 5U4GB
author_rank: Super Contributor
timestamp: September 20, 2025, 09:56:49 am
content: For anyone working with these, Tool Scientist has just posted an interesting video on reverse-engineering the diagnostic capabilities hidden inside Milwaukee tool batteries:

author: voltsandjolts
author_rank: Unknown
timestamp: September 20, 2025, 11:08:16 am
content: The ever-present Cyclotron beat you to it last week...https://www.eevblog.com/forum/chat/milwaukee-batteries-cracked/

author: 5U4GB
author_rank: Super Contributor
timestamp: September 20, 2025, 11:13:51 am
content: Ah, missed that one, I did a forum search on the YT channel name but didn't get any hits so assumed it was new info.
Dick Smith K-3203 Kit - Page 1
Forum section: electronics / repair

author: LRTNZ
author_rank: Newbie
timestamp: March 05, 2022, 08:01:37 am
content: Hey EveryoneMy dad and I have recently been going through some of his older electronic kits he has around, and putting them together.One of the ones we found was a Silicon Chip K3203 Kit, which we have not been able to find the schematic for. Of coursewe have a copy of all of the Silicon Chip magazines around the April 2002 one that has the schematic in it.https://www.siliconchip.com.au/Issue/2002/April/Easy-To-Build+Bench+Power+SupplyI was wondering if anyone would happen to have this schematic handy, as without turning the house upside down, I am worriedthat we will not find it.Many thanks for any help anyone can provide.

author: Shock
author_rank: Super Contributor
timestamp: March 05, 2022, 08:52:41 am
content: I think I have a copy of that month, let me have a look and I'll send you a pm.

author: LRTNZ
author_rank: Newbie
timestamp: March 06, 2022, 06:56:56 am
content: Just as an update - thanks to shock, we found that we were missing the main PCB, which was found, along with the construction article.

author: simba15
author_rank: Regular Contributor
timestamp: March 07, 2022, 02:14:29 pm
content: Are you able to share it here?Looks like a nice supply.Thanks,
dick smith q-1024 multimeter  - Page 1
Forum section: electronics / repair

author: philcolbourn
author_rank: Newbie
timestamp: May 10, 2022, 02:43:17 pm
content: does anyone have a circuit?or photo of component side circuit board?

author: kaindub
author_rank: Regular Contributor
timestamp: May 12, 2022, 09:57:52 am
content: If I recall it’s a soc thst drives the meter. About the only thing you can measure and change are the divider resistors and capacitors. The brains is buried in a blob.

author: philcolbourn
author_rank: Newbie
timestamp: May 12, 2022, 02:05:26 pm
content: not this one, it's an analogue meter.2 resistors are damaged and another has been replaced.Battery electrolyte has done a lot of damage and destroyed a trimmer.I'm looking for exact values to repairThen I have problem of how to recalibrate it... my thoughts are:1) adjust meter rest to zero2) apply 50uA and adjust meter bias to FSD3) apply about 2A to 10A DC setting and adjust trimmer4) apply about 2A to 10A AC setting and adjust trimmer

author: themadhippy
author_rank: Super Contributor
timestamp: May 12, 2022, 02:27:10 pm
content: QuoteIf its pure analogue ,as in just resistors in series parallel combinations it shouldn't be to hard to trace out the circuit diagram and calculate there value
Did I brick the Hytera Radio? - Page 1
Forum section: electronics / repair

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 12, 2021, 08:15:38 pm
content: http://setronics.net/wp-content/uploads/descargables/Documentos-software/DMR/PD506/Manuales%20Tecnicos/WF_Hytera%20PD50X%20VHF&UHF1%20Service%20Manual%20R5.6%2003-17-14.pdfHopefully Virus Free.Page 109 -> J4 there is a can who I pushed in when I tried to get the Front Plastik off. I dont realise there is on top something to unscrew....So I tried to lift that can up truth a small vent hole and what happen... The needle brake......So how to remove that can?Hopefully under nothing is damaged.Thanks

author: geggi1
author_rank: Frequent Contributor
timestamp: January 13, 2021, 09:22:39 pm
content: The can is probably soldered down.Hot air might be an option but you must be careful because the components are small.it might also be possible to remove the can with a soldering iron.

author: Lord of nothing
author_rank: Super Contributor
timestamp: January 13, 2021, 10:40:52 pm
content: How is the can soldert? I could not see any.

author: geggi1
author_rank: Frequent Contributor
timestamp: January 16, 2021, 03:12:25 pm
content: the can is usually soldered on the edge with a thin layer of solder on the edge.
Did I ruin this circuit board?? IPAD PRO 10.5 A1709 - Page 1
Forum section: electronics / repair

author: ibroke1t
author_rank: Newbie
timestamp: September 26, 2023, 03:48:01 am
content: I came across a free ipad with a broken charging port, so I decided to take a crack at it since the part was only $10.I got to the charging port that's soldered to the circuit board and was a little impatient. It appears I damaged the copper layer and will no longer be able to solder the new charging port onto the circuit. Can someone please let me know if this can be repaired, and if so how?FYI: I bought flux (rosin paste flux H50) and had some thin solder (60/40 rosin-core .032" diameter) to try and lay down a fresh layer on the copper but it's not taking.-see pics for more details

author: ataradov
author_rank: Super Contributor
timestamp: September 26, 2023, 05:43:48 am
content: The pictures are way too low resolution, but if the pads are ripped off, then yes, there is no easy way to recover it.Especially not with that soldering iron. It would be extremely challenging to do anything with this iron even for a person that did this a 100 times using proper equipment.It would also be really hard to remove the connector without using a hot air rework station without causing damage.Majority of ripped pads seem to be ground, so it is in theory salvageable, but you will need proper equipment and skills.I googled some images of the board. This is not even a connector, it is just a flex PCB to rigid PCB direct soldering. It is actually would be doable using that soldering iron (obviously still not advised). But recovering would be next to impossible using any tools.

author: ibroke1t
author_rank: Newbie
timestamp: September 26, 2023, 06:06:58 am
content: I had a feeling not having the hot air station was going hang me up.. I appreciate the input. I'm going to eventually just try to install the port just for practice before I trash. Any pointers would be great!

author: ataradov
author_rank: Super Contributor
timestamp: September 26, 2023, 06:09:21 am
content: There is no point in trying, it will not work. If the pads are ripped off, it will be a huge waste of time.It would have been possible to do a full replace using just the iron, it is much easier compared to a real connector. But this is not something you do on a first try. On a first try this would be a challenge even with proper equipment.
Difficulty turning on the oscilloscope XDS3104D - Page 1
Forum section: electronics / repair

author: azemati
author_rank: Contributor
timestamp: March 02, 2021, 12:11:44 pm
content: HiI have a XDS3104E oscilloscope from OWON company,which unfortunately when the device turns on, the light comes under the keys, but the device does not turn on.After releasing the key, the device turns off again, I checked the power supply of the device but it was correctIf anyone knows about this, please guide me

author: bob91343
author_rank: Super Contributor
timestamp: March 02, 2021, 10:47:36 pm
content: You need a service manual. There might be a reset you can try, often power up while holding certain buttons.

author: seronday
author_rank: Regular Contributor
timestamp: March 02, 2021, 11:29:41 pm
content: Does the Power ON / OFF Button change colour from Red to Green when you press it to turn the XDS3104D On ?The Power Button does require a Long press ( about 4 seconds ) to turn the instrument On.Regards.

author: ttx450
author_rank: Regular Contributor
timestamp: March 03, 2021, 02:15:00 am
content: Quote from: azemati on March 02, 2021, 12:11:44 pmIs this required to hold down keys when starting?"After releasing the key, the device turns off again"sounds like a reboot

author: azemati
author_rank: Contributor
timestamp: April 18, 2021, 09:00:51 am
content: That's rightI do it but it still does not turn on
DigElec model 824 Eprom Programmer service manual and help sought. - Page 1
Forum section: electronics / repair

author: Paceguy
author_rank: Regular Contributor
timestamp: June 11, 2025, 02:14:13 am
content: I picked up a DigElec 824 portable eprom programmer yesterday. It powers on but the display doesn't light up. I popped it open and noticed that there are a couple of electro caps that have bulged. I would like to get the power supply up to spec before going any further. Would anyone in this group happen to have any service info showing rail voltages and test points? It would be very much appreciated if someone could help me out.

author: m k
author_rank: Super Contributor
timestamp: June 22, 2025, 07:21:23 pm
content: Microcontroller.net has few photos, but maybe you want few of your own.How much is a battery voltage?TTL chips have voltage pins, 1488 drivers also.What types are TO-220 etc. components around power out connector?Among capacitors are coils, all are possibly for different voltages.

author: Paceguy
author_rank: Regular Contributor
timestamp: June 23, 2025, 11:00:19 am
content: Good news! I managed to get it up and running. Appears to have been a bad connection. The display is nice and bright, but it sometime dims a bit. I'll have to find out what causes this dimmong.

author: Paceguy
author_rank: Regular Contributor
timestamp: June 23, 2025, 11:07:19 am
content: The 824 has a built in UV lamp and slide-out drawer for erasing eproms. Mine is missing the entire lamp assembly but has the slide out drawer. Does anyone know how I could add a UV lamp? It would have to be low profile and fit inside the 824. Approx. 6 inches long and 2.5 inches wide.

author: m k
author_rank: Super Contributor
timestamp: June 23, 2025, 05:28:15 pm
content: Check UV-LEDs, correct wave length is available.They are fast, but I've only tried close contact distances.I read that the programmer has a removable software pack, is it mandatory or an add-on?

author: Paceguy
author_rank: Regular Contributor
timestamp: June 24, 2025, 11:07:40 am
content: The plugin is mandatory for operation.

author: Paceguy
author_rank: Regular Contributor
timestamp: June 24, 2025, 11:14:30 am
content: Would it be possible to mount 20-30 or so of the UV LED's onto a piece of perf-board the length and width of the slide in tray (drawer)and mount it about over the tray (drawer) by a couple of mm's? Do you know what wave length I would need ?

author: madao
author_rank: Frequent Contributor
timestamp: June 24, 2025, 05:17:38 pm
content: only user Manualbut better than nothing :-)

author: m k
author_rank: Super Contributor
timestamp: June 24, 2025, 06:58:46 pm
content: I can't see any reasons why discrete LEDs couldn't do it.But can't think you need that much of them either.wavelength is stated to be as 253.7 nm, so 260 nm is just fine.Search UVC disinfection LEDs.My LEDs are like those with six way circuit boards and double +/- pads.
Digilent Zybo-z7 replacing broken choke - Page 1
Forum section: electronics / repair

author: Falowod_Jerzy
author_rank: Newbie
timestamp: January 14, 2024, 04:47:55 pm
content: Hi, unfortunately I broke off one of the chokes on my zybo-z7 fpga board. It is the L1 on the schematic [https://www.mouser.com/pdfdocs/zybo_z7_sch-public.pdf]. Connectors of said element are non-existent, so I am not able to solder it back on, thus I am looking for a replacement part. I was looking for a BOM, or any other parts list, but I was unable to find them. My only clue is a resistance of similar chokes (around 2.4 Ohm) and it’s size which I measured myself.Does any of you fine people have any insights of what the inductance of this part may have been?The choke was located on one of differential lines for HDMI, so I guess that it must match three remaining chokes. In case of me not being able to find a replacement should I replace them also, or can I just solder whatever choke fits the footprint?
Digital frame - screen does not work after reconnecting ribbon cable - Page 1
Forum section: electronics / repair

author: VelvetVinz
author_rank: Newbie
timestamp: December 28, 2021, 06:07:36 pm
content: Hello everyone!I am new to this forum and I am actually just a hobbyst, playing with electronics either for fun or trying to repair stuff.I disassembled an old digital picture frame (kodak easyshare sv710) because the power supply seemed to have some issues (power going off and on and the cable being apparently ok).When doing this, I also disconnected the ribbon cable of the screen from what it seems to be a ZIF connector, but when I put everything back in place, the screen does not work anymore.I am wondering what the hell I might have messed up when disassembling the thing: could it be that the 26 pins of the cable are not perfectly touching the correspondent pins from the connector?Have a look at the pictures below.Thanks for your comments, suggestions, tips or any other help you might able to provide!CheersThe pictures:- The screen of the frame with the ribbon cable seemingly well connected and the clip/drawer of the ZIF connector locked- The ribbon cable connected to the ZIF connector and locked- The ribbon cable disconnected and the clip of the ZIF connector wide open

author: m3vuv
author_rank: Super Contributor
timestamp: December 29, 2021, 12:43:29 pm
content: did it display anything before you took it apart?

author: VelvetVinz
author_rank: Newbie
timestamp: January 01, 2022, 08:50:06 pm
content: Yes, it did. It just displayed pictures and menu. It worked fine before I disassembled it to try to fix the power supply issue.
Digital Handheld Capacitance Meter DM-6013 had zero adjust issue [SOLVED] - Page 1
Forum section: electronics / repair

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: December 08, 2024, 09:09:57 pm
content: Digital Handheld Capacitance Meter DM-6013 had zero adjust issue Test equipement : Digital handheld capacitance meterModel number : DM-6013Brand : PeerTronikManufacturer : Lutron, Taipei, TaiwanDisplay : LCD 3 1/2 digitsI recently had to repair my faithfulDM-6013 digital capacitance meter. It was no longer possible to zero the meter, by rotating the dedicated front panel potentiometer. Minimum offset value obtainable was now 20 pF. This offset could be observed up to the 200 nF scale.A replacement of IC4 (TL062) solved the problem. As I had no TL062, a functional/pin compatible TL072 was used in place. An added quality DIL-8 socket now eases further replacement.IC9 (CD4066) also gained a DIL-14 socket but the original IC is still in place, because it turned out that it was not implied in the described failure.After repair, the meter can now easily be zeroed. A verification with a 91 nF 1% capacitor displayed 91,8 nF which is sufficient for my use.TE schematic is attached below.Update #1 : typo
Digital loop tester repair - Page 1
Forum section: electronics / repair

author: fant
author_rank: Contributor
timestamp: October 26, 2024, 03:18:46 pm
content: I have a Kyoritsu 4120 Digital PSC-Loop tester that suddenly stopped working.It is used to measure the Ground resistance for an electrical system.Pictures annexed.It was working well, but suddenly it stopped and now during measurement shows 1 and nothing else.The three neon bulbs are working fine and the measurement timings are good.Anybody has the schematic diagram?Of course already tested semiconductors, diodes, resistors, fuses.Thank you

author: fant
author_rank: Contributor
timestamp: October 27, 2024, 09:53:13 am
content: I have seen that the ROBIN KMP4120 is the same instrument.Any schematic about this ROBIN?Thank you in advance
Digital Microscope ADSM302 supplied with way to much voltage - Page 1
Forum section: electronics / repair

author: fabfab
author_rank: Newbie
timestamp: February 19, 2020, 03:40:34 pm
content: Hi there.Accidently I supplied my ADSM302 Digital Microscope with 15 V (and 3Amps) for about 5 seconds - instead of 5V.Surprisingly it didn't like it and emitted some smoke.On the picture you can see a burned-up smd component next to the micro-usb power connector.I would be able to replace it, but have no clue on what it is.Can you give me a hint?Thank you.

author: fzabkar
author_rank: Super Contributor
timestamp: February 19, 2020, 07:05:11 pm
content: The ET9528 is an overvoltage protection IC with an Internal Overvoltage Lockout of 6.1V and a VIN Operating Range of 2.5V to 36V. I'd say there is a good chance that nothing else has been damaged.http://www.etek.com.cn/en/product.asp?ID=215

author: fabfab
author_rank: Newbie
timestamp: February 26, 2020, 03:59:31 pm
content: Thank you blueskull, thank you fzabkar,Both, the TVS diode, as well as the ET9528 did sacrifice and shortened to GND.I unsoldered them both and then applied 5v to the circuit, which seem undamaged (screen did power up / 300mA current drawn).So, now i'd like to replace them both, but didn't find any place to buy a replacement.I didn't find any ET9528 online.Is there a generic, which with I can replace the ET9528 and do you have an idea where I can get it to germany?Where would I buy a TVS with a 5.6V or 6.2V breakdown TVS with nominal reverse standoff voltage of 5V?How do you search for such components online?What supplier do you contact? aliexpress?Thank you for your awesome help and sorry for my newbie questions.

author: fabfab
author_rank: Newbie
timestamp: February 28, 2020, 06:47:19 pm
content: Does anybody has a hint for me, where to look for an replacement for the SOT23 regulator?The specification is here:http://www.etek.com.cn/en/product.asp?ID=215All I could find was a SOT with Input/Output Pins reversed:https://www.mouser.de/datasheet/2/308/NCP360-D-85706.pdfThank you.

author: syau
author_rank: Frequent Contributor
timestamp: February 29, 2020, 06:59:12 am
content: Quote from: PeDre on February 29, 2020, 06:18:12 amLooks like a WS3202E61-6/TR, available from utsource.
digital multimeter that stopped working by itself - Page 1
Forum section: electronics / repair

author: amir.razzaqi
author_rank: Contributor
timestamp: July 19, 2023, 09:01:59 am
content: Hello guysI have a Victor VC97 DMM that I have not used it since last year, (I stored it without battery). I wanted to use it couple days ago and when I insert a new 9.0V battery the multimeter backlight turned on and the buzzer start buzzing and LCD showed "ERR 0" I remove battery and insert again for a few times and the same thing happened (the error sometimes changed to "ERR 1") after that the error goes away but the multimeter din not work in most ranges (only continuity test and frequency meter and capacitor meter in nano farad ranges works). I checked the fuses and 3.3v regulator and EEPROM all was OK. Now I don't know where to start.I appreciate anyone with any advice.the board photos:https://drive.google.com/drive/folders/10y5x8bgkodZpZq_Hk_wPlbiRgFQvfxP7?usp=drive_link

author: Gyro
author_rank: Super Contributor
timestamp: July 19, 2023, 12:29:14 pm
content: Is this related to your other VC97 (mV) thread? You say the EEPROM is ok, have you been trying to read the contents without proper voltage level translation (I think you used 5V in the other thread). I'm wondering if it caused more damage on this meter than the other one.https://www.eevblog.com/forum/chat/dmm-problem-in-dc-millivolts-range/

author: amir.razzaqi
author_rank: Contributor
timestamp: July 19, 2023, 02:25:11 pm
content: Quote from: Gyro on July 19, 2023, 12:29:14 pmNo, I have two of them. I compare both EEPROM (after the first one stop working) and only 24 byte of 256 byte was different. This bytes maybe related to calibration issue.
Digital reverb SoC troubleshooting  - Page 1
Forum section: electronics / repair

author: FranciscoPerez
author_rank: Newbie
timestamp: February 29, 2024, 07:51:26 pm
content: Hi guys.I’m trying to troubleshoot an issue in a digital reverb circuit that’s driving me nuts. Here’s the schematic. Hope you could give some advice.its the reverb effect section of a musical instrument amplifier.The unit worked great until one day it began making a harsh noise which was produced by u202 , a bd3201 reverb SoC. I didn’t have a scope at the time and decided to replace it. Hearing at the symptoms someone said probably the DRAM inside the bd3201 had failed and was making errors. After replacing the noise went away, but u202 is not outputting any signal and I’m not getting any reverb sound at all. Dry signal works as expected and the amplifier is usable, but without any reverb effect to it.Now I have a scope available so I could troubleshoot this further, but I’m quite a newbie in digital circuits and don’t know where to start. I’d like to check mostly if the adc u201 before the reverb chip is outputting the digital converted input signal and whether the bd3201 is receiving a good digital input signal . My scope also has a function generator , so I can inject say a 500hz signal to the amplifier, for testing.What should I expect to see when probing the adc output pin and the bd3201 input? Any other troubleshooting advice I could perform to trace down the problem is strongly appreciated!Thank you all.CheersFran

author: FranciscoPerez
author_rank: Newbie
timestamp: March 06, 2024, 03:26:01 pm
content: I grabbed a scope, and probed all pins of bd3201 hoping someone more experienced could shed some light on this.Injected a 0,2v 500Hz sin signal through the amp's input, and this is what I got:BD3201 Pin 01 Digital OUT: IMG_9277.jpgBD3201 Pin 03 and Pin 04 XTAL IN and OUT: IMG_9280 and IMG_9281BD3201 Pin 16 DIGITAL INPUT : IMG_9278BD3201 Pin 14 VDD: IMG_9282BD3201 Pin 13 GND: IMG_9283BD3201 Pin 12 !Reset: IMG_9284BD3201 Pin 11 Sysclock: IMG_9285BD3201 Pin 10 Bitclock: IMG_9286BD3201 Pin 09 Wordclock: IMG_9287All signals but the Digital OUT look right to me. Can you spot something which does not look good??
Digital storage board repair? - Page 1
Forum section: electronics / repair

author: Mjkdar
author_rank: Newbie
timestamp: March 10, 2020, 10:33:03 pm
content: I would call myself a intermediate "beginer"in electronics, but a beginner with oscilloscope. I picked up an analog oscilloscope cheap. Opened it up to clean a couple of pots, and noticed the digital board had been repaired or altered. A picture is below of jumper wires attached in several locations as well as a resistor type thing. I realize it's probably impossible from looking at a picture, but I was just wondering if anyone had an idea why this might have been done? Also if it only affects the digital storage board?

author: james_s
author_rank: Super Contributor
timestamp: March 11, 2020, 12:02:56 am
content: Without even knowing exactly the model of scope it's very difficult to say. It's possible those are factory bodge wires to correct errors in the PCB, that used to be common back in the days before modern CAD. PCBs were laid out by hand, errors on large boards were common and a re-spin of a large board was very expensive.It's also possible that somebody tore up some traces replacing an IC and patched around them.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 11, 2020, 12:35:59 am
content: Tektronix 2201, and yes probably factory corrections.

author: Mjkdar
author_rank: Newbie
timestamp: March 11, 2020, 12:41:19 am
content: Give that man an A+ When editing before posting, I accidentally deleted the model. Indeed is a tektronix 2201.

author: james_s
author_rank: Super Contributor
timestamp: March 11, 2020, 01:55:26 am
content: Also I see now that the nameplate is visible, I was viewing on my phone and didn't scroll over far enough. Best way to co firm is find a picture inside another scope of the same model and see if it also has the oops wires.

author: Mjkdar
author_rank: Newbie
timestamp: March 11, 2020, 02:30:48 am
content: I saw a video online by someone who participates on this forumLooked like the jumpers "weren't" on his....Maybe a later repair.....
Digitec 304B Function Generator/Counter - Page 1
Forum section: electronics / repair

author: ErichKeane
author_rank: Newbie
timestamp: April 06, 2023, 06:41:45 pm
content: I picked up a Digitec 304B Function Generator/Counter, which came to me as 'won't turn on'. I spent some effort switching over from this strange 3 pin power plug to an IEC connector with quite a bit of effort. Then, I discovered that the switch on the power/output (for volts) was not functioning, but some contact cleaner + some cycles seemed to fix it. I had a few switches that seemed to have similar problems that were fixed by cleaning as well.As far as I can tell, most of the functionality seems to 'work' and do what it is supposed to, though there is something messed up with the screen. it SEEMS to show roughly the right value, but with an odd range for most. It also doesn't seem to light up WHICH range it is in, but I'm not sure what is wrong. Finally, there is a switch that seems to mess with the screen by moving the decimal point (it says 1 sec -> 10 sec, so that makes sense).SO, I think I have just about everything except the 'display' board working just about perfect. There might be some stuff that needs cleaning, but it seems to work fine otherwise. It has a fairly generous number of test-points all over the board, so I was hoping to find a manual that could help debug it (or at least show schematics), but I've had no luck.Anyone have an idea how to find one besides just google?

author: ErichKeane
author_rank: Newbie
timestamp: April 06, 2023, 06:46:44 pm
content: This is the ebay listing with some pictures for those who are interested:https://www.ebay.com/itm/295558299735Of note, this ebay listing:https://www.ebay.co.uk/itm/174155727629seems to be for the serial number 1 greater! So that is a coincidence!I've since switched from that plug to the IEC connector to make it usable, since those power cords seem unobtainable.

author: ErichKeane
author_rank: Newbie
timestamp: April 07, 2023, 12:27:22 am
content: Welp, this is moot now... I was running it while thinking through what could be happening (so not touching anything:(), and stuff started smoking. By the time I got to it, about a dozen small transistors, and a few of the ICs all burned holes in themselves. After I regained composure, I plugged it back in briefly, and the 5v rail on the board had gone to 40v, so i suspect that is what did it in. I don't think it was anything I caused, but even so, I've donated this project to the trash bucket :/Win some, lose some!
Digitech QC1933 intermittent issue. - Page 1
Forum section: electronics / repair

author: Stuart Coyle
author_rank: Contributor
timestamp: February 01, 2025, 10:37:06 am
content: I'm having issues with my old DSO, bought from Jaycar as a QC1933 which I believe is a rebadged Atten (at least the power supply has Atten on it).Yes, I know I should just buy a better scope but I have an in house accountant that I have to pass purchases by (wife).The scope will randomly freeze up. Display stays visible but nothing works. It was crashing after about a minute of operation.I have just pulled it apart and given it a good look over, clean and check of power rails. All +/-5 and 12V rails seemsteady, even when it freezes up. (it would be good to have a scope to check that properly...)The power supply seems fine.I found a dodgy solder joint on a 12V regulator, looks like one has been replaced at some time, which is odd since I bought it "new" fromJaycar. I resoldered the regulators just in case, the solder on them was looking pretty dry.Anyway, I cleaned it up, put some contact cleaner in the rotary encoders and such.I ran it for a while out of the case and it crashed a few times. Then after a while it ran fine, had it heated up enough or something?It's back together again and has run for a few hours without an issue. I don't trust that it is actually fixed.I'm at a loss for what the problem might have been. Anyone with an idea?

author: m k
author_rank: Super Contributor
timestamp: February 08, 2025, 07:24:32 am
content: Intermittent contact problems are nasty.If you can use it when it's open you can try cooling and heating from here and there.That's not much, but it's pretty much what you have, you can also try knocking stuff.
Dim LCD display on old Casio calc - Page 1
Forum section: electronics / repair

author: spanakop
author_rank: Contributor
timestamp: July 07, 2021, 04:05:51 pm
content: Hi all. I have an old Casio fx-7000GB calculator (I love these old Casio's), where the display is quite dim. Even when I adjust the contrast, it still need to tilt the calculator at an angle before I can see a decent display. The batteries are good, all the functions are working, there are no inoperative buttons, just the dim display.Is there anyway to fix this problem, or is it just a worn display (if there is such a thing)?

author: Gyro
author_rank: Super Contributor
timestamp: July 07, 2021, 04:45:09 pm
content: It's probably contamination or ageing (compression) of the conductive rubber 'zebra strip' that connects the LCD to the calculator PCB (forum search zebra strip to get a better ideas and probably some images).The question is whether you can get the calculator case apart without damaging it, it depends whether you want to maintain it in perfect cosmetic or best working condition..You can usually clean up the PCB pads, strip and edge of the display with a little IPA - checking under a magnifier that you don't leave any paper or fabric fibres on the contact surfaces.

author: Haenk
author_rank: Super Contributor
timestamp: July 08, 2021, 02:41:17 pm
content: As this was one of my first calculators to own, I can confirm that the display has always been awful.Those cheap LCDs will get even worse over time though, probably through chemical aging, however there are no replacement parts available (of course) and if I remember correctly, the zebra strips are bonded to the display and PCB. (Which also means no fixable contact issues...)Putting your lighting at the right angly is the best way to use it (and has been back then).

author: spanakop
author_rank: Contributor
timestamp: July 09, 2021, 09:01:15 am
content: Thanks guys. As I'm not seeing any missing segments or lines in the display and the problem is display wide not in specific areas, so I'm less inclined to think it's a bad connection.My 'fix' is to angle the calculator at an angle to see what's going on more clearly, as Haenk mentioned. Interesting to know that this was a problem when it came out originally.I'll open it up this weekend and have a look inside. It's not my main calculator anyway, I have another eight calcualtors to use if I need to, a mix of old a new (I even have an old slide rule).
Dimmer Pack Repair - Page 1
Forum section: electronics / repair

author: paul_g_787
author_rank: Frequent Contributor
timestamp: October 13, 2024, 11:46:17 am
content: My Transcension 4 channel dimmer pack CDP405 stopped responding to DMX following a suspected power surge.My first point of call was the power supply. It has a 1x240V to 2x15V transformer. Then a full wave rectifier into a 7805.My voltages after the transformer 15VAC on each secondary, and the pulsating DC after the rectifier looks normal. However my 7805 was outputting 9V DC (measured using a BM786).I replaced the 7805 now getting 4.9 V out but I have a pulse on the DC line. I probed it with the scope.I have attached an image of the scope display.What could be causing the pulsing? It doesn't look to me like the usual waveform I would expect for a dodgy capacitor. Perhaps indicating a short somewhere?Any idea what to check next?

author: Harry_22
author_rank: Frequent Contributor
timestamp: October 13, 2024, 05:58:33 pm
content: Hi Paul!You have 100 Hz pulsations at 7805 output. This means that you have them also at the input.Check the bulky capacitor.Harry

author: paul_g_787
author_rank: Frequent Contributor
timestamp: October 13, 2024, 09:02:38 pm
content: That would make sense. I will replace it when I come back to this in a couple weeks and post back.Perhaps it is heat damaged over time from it's close proximity to the 7805....Might replace the smaller output capacitor too as it is also right next to it. And bolt a small metal strip to the 7805 as a heatsink to take the heat up and away.The PCB was a bit discoloured under the 7805 too.
SOLVED - DIN style 6 pin connector identification - SmartDrive wheelchair motor - Page 1
Forum section: electronics / repair

author: thm_w
author_rank: Super Contributor
timestamp: October 18, 2022, 09:10:26 pm
content: This is from SmartDrive MX1+ wheelchair motor. Pins welded themselves inside the connector, want to check if its possible to replace the connector at all.Anyone recognize the connector or logo? Looking through digikey at the moment.Plug description:- 6 pin DIN style connector, with latching portion above- 13.5mm OD on the plug side- "G" symbol on the connectorReceptacle:- pin diameter ~1.5mm- o-ring sealSeems reasonably well designed with sealing, silicone. Board is not coated though.edit: the dimension seems to match a M16 connector.

author: fzabkar
author_rank: Super Contributor
timestamp: October 18, 2022, 09:29:47 pm
content: The logo appears to belong to "binder":https://www.binder-connector.com/en/It's not the right connector, but it might set you in the right direction:https://au.rs-online.com/web/p/industrial-circular-connectors/1152641

author: thm_w
author_rank: Super Contributor
timestamp: October 18, 2022, 09:48:15 pm
content: Quote from: fzabkar on October 18, 2022, 09:29:47 pmoh that helps a lot, yeah not "G" but "b". Binder 440 series.Definitely not cheap, but apparently the whole system was ~$8k.https://www.farnell.com/datasheets/19167.pdfPlug side: 99-4818-00-06Receptacle side: 09-4819-15-06 or 09-4819-25-06

author: thm_w
author_rank: Super Contributor
timestamp: November 08, 2022, 01:58:38 am
content: The reason the connector was welded due to a dead short on that main PCB from BAT to GND. I tried plugging it in again and it completely vaporized the molex contact. BMS?There is a small protection diode "F9 CK" beside the connector. Looked burned but removing it did not resolve short.Q5 and Q6 FETs are shorted D to S, I missed that initially (probes not sharp enough). Probably happened when the filter capacitor fell off? it was the only thing on the board that wasn't glued... FET part number FDD13AN06AOrdered the Binder connectors ($$), soldered them with the existing wiring, and it seems to be working.It won't run the motor until you push it a bit first, very similar to an electric push scooter.thanks

author: fzabkar
author_rank: Super Contributor
timestamp: November 08, 2022, 05:47:45 am
content: Could "CK" be a 30V bidirectional TVS diode, SMBJ30C?https://www.diodes.com/assets/Datasheets/ds19002.pdfhttps://m.littelfuse.com/~/media/electronics/datasheets/tvs_diodes/littelfuse_tvs_diode_smbj_datasheet.pdf.pdf

author: thm_w
author_rank: Super Contributor
timestamp: November 08, 2022, 08:54:48 pm
content: Quote from: fzabkar on November 08, 2022, 05:47:45 amIts not SMB, a bit smaller.But, I think you are almost certainly right that its a 30V TVS or similar. The battery pack is 24V (~28V charged), so a 30V TVS would make sense.edit:Pinout was (female side of connector going CCW):1 - Brown - Gnd2 - Blue - Control3 - Red - Batt +4 - Orange - Gnd5 - Yellow - Control6 - Black - Batt +
diode blown up - Page 1
Forum section: electronics / repair

author: oil_Lamp
author_rank: Newbie
timestamp: July 30, 2024, 03:15:10 am
content: Hello dear community,i have a question about a repair attend.i have bought a LCD display for a tablet. i installed it and during charging i accidentally pulled the LCD ribbon cable out and a SMD started to smoke.there are 2 diodes on pic. both are shorted (diode test) and one of them is even blown up.The question is, can i solder any small diode as replacement or it must be a SMD and with very specified values for a diode?Lables: S4 and 4PS4 is blown upThanks in advance

author: gamalot
author_rank: Super Contributor
timestamp: July 30, 2024, 03:52:52 am
content: S4 is 1N5819 or SS14 Schottky diode.4P is MM1Z5V6 Zener diode.
Diode D12 on Pickit 4 - Page 1
Forum section: electronics / repair

author: odessa
author_rank: Regular Contributor
timestamp: April 10, 2025, 10:52:24 am
content: Hi,Had an incident with my Pickit 4 today and seem to have let the magic smoke out of D12 on my Pickit 4.Has the marking DW 93 on itAnyone know what it is ?

author: adam7
author_rank: Newbie
timestamp: April 10, 2025, 11:04:19 am
content: It is BZT52H-B13,115.https://jlcpcb.com/parts/componentSearch?searchTxt=BZT52H-B13
Diode ID - Page 1
Forum section: electronics / repair

author: ahakman
author_rank: Regular Contributor
timestamp: February 08, 2024, 09:58:00 am
content: Can anyone help identify these diodes? I have a bunch of examples of what I think are the same diodes, but they have such minimal markings on them, it's hard to tell.The bodies are really short, have a blue cathode marking, and blue "4" and a letter. On 3 different boards I have, the letters are different, but otherwise they all look the same (and I'm guessing they are the same component) - the letter is a date code or factory code or something?On one board, they're labeled "4 K", on another board that's exactly the same, but probably produced at a different time, they're labeled "4 A", on a slightly different board, but manufactured by the same company in a very similar device, they're labeled "4 D". These are probably designs from the late 80's or early 90's, with build dates in the early to late 90's. The middle picture is a little blurry - my phone wouldn't focus properly. It's very clearly an "A" on that one. I don't have a picture of the "4 K" variety, but they look identical, except for "K" instead of "A" or "D"Anyone have any ideas? Are they just 1N4004's??

author: madires
author_rank: Super Contributor
timestamp: February 08, 2024, 11:05:51 am
content: Used for a bridge rectifier? What is the diameter of the diode's body?

author: ahakman
author_rank: Regular Contributor
timestamp: February 08, 2024, 11:31:17 am
content: No, not used as a bridge. The main bridge rectifier is a large integrated one mounted to a heatsink.Some kind of small signal (to medium signal) diodes. These boards have a mix of diodes on them - there's typical glass diodes, but most (but not all) of them are labelled as ZD###, so most likely zeners. There's these, and there's some other glass diodes that are marked as normal diodes on the silkscreen designator, that have a white and green stripe on the glass package.These ones are 2.5mm dia x 2.8mm long measuring just the body. The legs are 0.6mm dia. The lead spacing (as the leads are formed) is about 10 or 10.5 mmThe ones that need to be replaced need to be replaced because the electrolyte from leaking capacitors ate away the legs of the diodes, not because they failed (well, one failed, but that's because a large zener went short that was very close to a leaking cap)Also, the forward voltage drop is 0.471 - a bit lower than a normal silicon diode - Schottky? Germanium??

author: madires
author_rank: Super Contributor
timestamp: February 08, 2024, 12:52:39 pm
content: Assuming a test current of 1mA, a Vf of 0.47V would be too high for a Germanium diode. Maybe some old Schottky.