hybridfree/eevblog-posts huggingface dataset:
Unknown ic in power supply of TCL U55E5800FS TV - Page 1
Forum section: electronics / repair

author: Kartman
author_rank: Contributor
timestamp: September 26, 2019, 07:23:28 am
content: I have a TCL U55E5800 tv whose power supply has failed. It looks like the root cause was a 100pF 1kV cap as part of the snubber that died then caused the gate junction of the mosfet to break down and blow up the controller chip. The cap, mosfet and diode have been identified, but the sot23-6 pwm controller is dead. How do I know this? The junction between the gate drive and 0V is a couple of Ohms. For those who have a schematic, the designator is U302Anyways, the markings are: 283G12 and 284B.From looking at the circuit, the pins roughly are:1 VCC2 current sense3 gate drive4 0V5 some sort of sense input6 feedbackI had a look at OnSemi, their NCP2150 sort of looked similar, but rotated 180degrees.If anyone has the schematic, parts list or a suggestion it would be appreciated.

author: amyk
author_rank: Super Contributor
timestamp: September 26, 2019, 11:58:20 am
content: OB2283ASearch pictures of it to confirm.Edit: OB2283A, not just 2283. Details here:https://www.wendangwang.com/doc/0582a3710bac1bbae9b36b38

author: Kartman
author_rank: Contributor
timestamp: September 27, 2019, 03:47:49 am
content: Many thanks! It looks like the chip. The next problem is where to buy some.

author: don.r
author_rank: Frequent Contributor
timestamp: September 27, 2019, 04:17:40 am
content: You can take your chances on aliexpress but it might not be genuine.https://www.aliexpress.com/item/32790107064.html

author: Kartman
author_rank: Contributor
timestamp: November 03, 2019, 03:34:34 am
content: I managed to have success in repairing this tv. It was not straightforward - the OB2283 chip is close, but not quite the right one methinks. The OB2283 has latching over temp/over volt circuitry, whereas the original chip (whatever that is) did not. After much fiddling, I bridged a 33k resistor across the existing 33k resistor connected to the PRT pin. This told the chip there was no over temp and no over volts. Once i did this, the power supply jumped into life.I got the mosfets and OB2283 chips off Aliexpress. There was a surface mount diode that I replaced with a 1N4148 leaded part and a 100pF 1kV cap replaced.Another TV saved from the scrap heap. Thanks to all that contributed. Great success!

author: amyk
author_rank: Super Contributor
timestamp: November 03, 2019, 03:40:10 am
content: Yes, that was likely the difference between a plain OB2283 and an OB2283A.
unknown IC on air purifier - Page 1
Forum section: electronics / repair

author: harveyradar
author_rank: Contributor
timestamp: March 05, 2022, 10:37:46 am
content: Can anyone identify this IC please?14 DIL SMDmarkedT2680NFY40thanksHarvey

author: fenugrec
author_rank: Frequent Contributor
timestamp: March 05, 2022, 09:53:54 pm
content: It'll help to give some context on the IC, i.e. what is it wired to, circuits around it etc. Could help narrow down the category.
unknown mosfet 2521A? - Page 1
Forum section: electronics / repair

author: hercegovac
author_rank: Contributor
timestamp: June 08, 2019, 09:52:11 pm
content: any help figuring our replacement component for the part labeled 2521A will be appreciated .

author: Chriss
author_rank: Frequent Contributor
timestamp: June 09, 2019, 06:28:08 am
content: Hi!Can you pls give a description about the circuit where this mosfet is located?Or maybe a drawing?Sent from my SM-J500F using Tapatalk

author: hercegovac
author_rank: Contributor
timestamp: June 10, 2019, 04:00:54 pm
content: So it is a control board for GODOX AD200 flash. Image of the control board is attached, the mostfet when measured with Voltmeter shows short between gate and source (assuming it is mosfet).

author: Chriss
author_rank: Frequent Contributor
timestamp: June 10, 2019, 04:18:50 pm
content: Take it out from the board and check it if it is still in short.Make a picture of the region so we can try to flow the wiring/trace..

author: fzabkar
author_rank: Super Contributor
timestamp: June 11, 2019, 04:13:15 am
content: 26Z08 appears to be an LDO regulator (there are large capacitors on each pin). AFAICT, both parts have circuit references of the type "Unn", so they must be ICs. I suspect that 2521A could also be an LDO. Do the Vouts go to the Vcc pins of the other ICs?
Unknown part. - Page 1
Forum section: electronics / repair

author: eurgenca
author_rank: Regular Contributor
timestamp: January 13, 2021, 08:19:20 am
content: Hello.Can someone tell me what is this unknown part. It is act like open circuit.Thanks, Sebastijan.

author: ataradov
author_rank: Super Contributor
timestamp: January 13, 2021, 08:56:55 am
content: Where was it found? It may be a spark gap, in which case being open circuit is normal.

author: eurgenca
author_rank: Regular Contributor
timestamp: January 13, 2021, 09:05:58 am
content: PSU in star tps100 printer. It is between a1 and a2 on triak.

author: eurgenca
author_rank: Regular Contributor
timestamp: January 13, 2021, 09:23:32 am
content: AC line is feeded to bridge rectifier through triac. On DC side I get 25V. Triac is controlled by opto from secondary. If I bridge A1 and A2 PS starts.

author: ataradov
author_rank: Super Contributor
timestamp: January 13, 2021, 05:50:22 pm
content: This must be a spark gap. I see no other element that would make sense across a triac. Something else must be wrong.It is hard to see on the picture. Look though the glass with good magnification and see if it looks like something looks damaged or it looks like the circuit should not be open.It is possible that it is supposed to have low trigger voltage and they are relying on it to initially conduct to start, but that would be a very strange design.
Unknown part in kodak i2600 scanner for replacement or test - Page 1
Forum section: electronics / repair

author: wawinfo
author_rank: Contributor
timestamp: March 23, 2025, 04:53:19 pm
content: I have the kodak scanner i2600 main board that I attached its picture to identify unknown part, does anyone knows the type of this?

author: fzabkar
author_rank: Super Contributor
timestamp: March 23, 2025, 06:59:12 pm
content: "CR19" suggests that it's a diode.

author: wawinfo
author_rank: Contributor
timestamp: March 23, 2025, 07:02:39 pm
content: Quote from: fzabkar on March 23, 2025, 06:59:12 pmBut I tested it by multimeter in diode mode, no sign of diode dropped voltage, it opend in any directions

author: TimFox
author_rank: Super Contributor
timestamp: March 23, 2025, 07:08:41 pm
content: Quote from: wawinfo on March 23, 2025, 07:02:39 pmDid you measure it from the center lead to each end separately? I have used units in that package that had two diodes, from center to the other leads, such that it would not conduct from end to end.

author: wawinfo
author_rank: Contributor
timestamp: March 23, 2025, 07:46:06 pm
content: Yes I have good experience in electronic and repair, I checked it in every possible direction

author: TimFox
author_rank: Super Contributor
timestamp: March 23, 2025, 07:50:58 pm
content: In US usage, “CR” means diode (originally “crystal rectifier”). If you cannot measure continuity in any combination of connections, the part is probably “blown” (or the center lead has failed open).

author: fzabkar
author_rank: Super Contributor
timestamp: March 23, 2025, 09:04:04 pm
content: The diode appears to be wired to P7 and P8. What is connected P7 and P8? Could the diode be OR-ing two power sources?

author: wawinfo
author_rank: Contributor
timestamp: March 23, 2025, 10:16:27 pm
content: You are right, it is like connecting two power connectors

author: fzabkar
author_rank: Super Contributor
timestamp: March 24, 2025, 05:15:39 pm
content: Maybe something like these?https://assets.nexperia.com/documents/data-sheet/PMEG2005CT.pdfhttps://assets.nexperia.com/documents/data-sheet/PMEG3005CT.pdfhttps://assets.nexperia.com/documents/data-sheet/PMEG4005CT.pdf
Unknown Part in my Fluke 200 LAN Toner - Page 1
Forum section: electronics / repair

author: Glenn
author_rank: Newbie
timestamp: June 14, 2024, 06:24:38 pm
content: Hi Guys!I've got a second one of these Toner Tools were this Part has been knocked of by the Coax Connector above when i dropped it.I'm searching for the 3 legged Part labeled 6.00M. The Mask says U301, so it might be a VoltageDivider?I've got no clue what to search for!Can somebody help me?

author: fzabkar
author_rank: Super Contributor
timestamp: June 14, 2024, 07:05:42 pm
content: What are the markings on the adjacent 14-pin IC? My first thought is that 6.00M is a 6MHz oscillator, but I've never seen one in a 6-pin package.

author: squadchannel
author_rank: Frequent Contributor
timestamp: June 14, 2024, 07:27:42 pm
content: Crystal resonator.https://www.digikey.com/en/products/detail/ecs-inc/ECS-SR1-6-00-B-TR/332500

author: DimitriP
author_rank: Super Contributor
timestamp: June 14, 2024, 07:44:10 pm
content: This close to a connector ....I'd guess diode array for esd protection

author: BennoG
author_rank: Frequent Contributor
timestamp: June 14, 2024, 08:17:47 pm
content: my guess a 6.00Mhz clock generator.Benno

author: coromonadalix
author_rank: Super Contributor
timestamp: June 14, 2024, 11:14:19 pm
content: the chip next to it must be an mcu, see the resonator traces going to ...

author: Glenn
author_rank: Newbie
timestamp: June 15, 2024, 09:42:50 am
content: Thank You very much for the Link! Looks perfect! Already ordered!
Unknown pink-ish component - Page 1
Forum section: electronics / repair

author: morfi717
author_rank: Newbie
timestamp: June 19, 2023, 10:37:03 am
content: anyone has ideas on what the "bloated" pink-ish diode-looking element in the middle of the photo could be?

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 19, 2023, 02:12:58 pm
content: Glass body makes me think diode of some sort. EDIT: Lack of polarity stripe makes that unlikely. Knowing what we're looking at would be helpful, what is the board from? What is it supposed to do?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 19, 2023, 02:19:20 pm
content: thermisor maybe?

author: coromonadalix
author_rank: Super Contributor
timestamp: June 19, 2023, 04:07:23 pm
content: i would say a diode like 1n914 1n4148take a meter and check in diode ...

author: metertech58761
author_rank: Frequent Contributor
timestamp: June 20, 2023, 12:22:58 pm
content: Thermistor would be my guess as well.

author: xrunner
author_rank: Super Contributor
timestamp: June 20, 2023, 12:37:16 pm
content: Agree with the thermistor crowd. Most diodes have the cathode marked with a line (as in the picture you show).Although I could be wrong about this and many other things.

author: coromonadalix
author_rank: Super Contributor
timestamp: June 20, 2023, 03:52:30 pm
content: gas tube dischargethat smal?

author: floobydust
author_rank: Super Contributor
timestamp: June 20, 2023, 04:49:26 pm
content: What does the part measure for (in circuit) resistance, and while your finger heats it up. That will show if it's a thermistor.But all those all use MELF diode packaging - red glass, not this strange beige.As a GDT it doesn't have special PCB trace spacings or a path to ground.

author: morfi717
author_rank: Newbie
timestamp: June 21, 2023, 09:34:53 am
content: It was indeed a thermistor:) thanks!
Unknown plug - Page 1
Forum section: electronics / repair

author: harveyradar
author_rank: Contributor
timestamp: January 26, 2023, 07:14:58 am
content: Can anyone please help me by identifying this connector?Looks like it would normally used as a power connector for some sort of appliance. It is only polarised by the fact it is a right angle plug.It is being used internally on a microscope by a Chinese or Indian manufacturer for the illumination LED power.Thanks all for thinking about my problem.Harv.

author: timenutgoblin
author_rank: Regular Contributor
timestamp: January 27, 2023, 02:27:59 am
content: I don't know the exact name of this connector, but I found a connector type that is very similar. It looks like it might be a "D Tap" power connector. See below:Source:www.cinemachine.com.au/products/dtap-misc-3www.cinemachine.com.au/products/dtap-misc-2
unknown PWM controller - Page 1
Forum section: electronics / repair

author: moose
author_rank: Contributor
timestamp: February 22, 2023, 04:25:37 am
content: HiDoes anyone know what 6pin PWM controller this is...its on a (non-working) Black&Decker 18V Li-ion charger.thanks

author: Kim Christensen
author_rank: Super Contributor
timestamp: February 22, 2023, 04:51:57 am
content: It could be a R7731... Check the pinout and functionfrom the datasheetagainst your circuit.

author: moose
author_rank: Contributor
timestamp: February 22, 2023, 05:37:56 am
content: sheesh Kim..it certainly seems to be it...THANK YOU!As a matter of curiosity, is this a chip you've come across previously or are you familiar with the marking or...?

author: Kim Christensen
author_rank: Super Contributor
timestamp: February 22, 2023, 05:51:38 am
content: I just went and checked aSMD code pagethat I've used in the past. Maybe I got lucky with that one.

author: moose
author_rank: Contributor
timestamp: February 22, 2023, 06:43:06 am
content: now thats a 'double' thank you...excellent SMD markings lookup site!

author: fzabkar
author_rank: Super Contributor
timestamp: February 22, 2023, 08:55:53 am
content: I use this site:http://www.smdmark.com/en-US/search/code?id=dp%3D

author: moose
author_rank: Contributor
timestamp: February 22, 2023, 10:08:41 am
content: also excellent!thanks for that.
Unknown SMD Inductors of a Network Switch - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: December 26, 2024, 04:07:44 pm
content: Hello,I have a PCB of a network switch "GO-SW-16G" and by mistake I ripped off two inductors when I was cleaning it. Do you know what type/characteristics/footprint must have these inductors?

author: fourfathom
author_rank: Super Contributor
timestamp: December 26, 2024, 05:01:49 pm
content: Do those have four pads? They look like common-mode chokes, and there are plenty of these available for ethernet use. Look at TDK and Coilcraft.

author: 2X
author_rank: Frequent Contributor
timestamp: December 26, 2024, 05:41:47 pm
content: Quote from: fourfathom on December 26, 2024, 05:01:49 pmYes they have four pins so as you say must be common-mode chokes. I will make a search. Thanks you very much for your reply.

author: fzabkar
author_rank: Super Contributor
timestamp: December 26, 2024, 09:51:29 pm
content: Does this help?https://sfc.changhongeurope.cz/firmwares/CHIQ - L32G4000 (917A8JV)/service/L32G4000I--Circuit diagram.pdfhttps://www.taobao.com/list/item/747750229891.htmhttps://www.oneyac.com/product/26315608.html(WCM0805F2SF-801-N-FB)https://patentimages.storage.googleapis.com/10/4d/a6/d68621e0177034/CN213367806U.pdf(page 5)Essentially, the two chokes constitute a bandpass filter.

author: 2X
author_rank: Frequent Contributor
timestamp: December 28, 2024, 02:26:01 am
content: Quote from: fzabkar on December 26, 2024, 09:51:29 pmThanks for your reply. The design which fits with my PCB is the blackwhite that you posted.The only chokes that I found are the below. The one is 800 Ohm @100MHz (Replace part number: WCM 2012F2SF-801-N) like this on the attached pdf that you posted, but the other 100 Ohm @100MHz I can't find it... I fould a close value 90 Ohm @100MHz (WCM 3216F2SF-900T04). Do you beleive that this tolerance is acceptable? If you know any other site that I could find "2 LINE COMMON MODE CHOKE", please tell me."Original Value": YLM1206F2SF‑101‑AWCM 3216F2SF-900T0490 Ohms @ 100 MHzhttps://www.digikey.gr/en/products/detail/tai-tech-advanced-electronics-co-ltd/WCM-3216F2SF-900T04/17835962?s=N4IgjCBcpgbFoDGUBmBDANgZwKYBoQB7KAbRAA4BmAdjAgF0CAHAFyhAGUWAnASwDsA5iAC%2BBAEzjyABgQhkkdNnxFSIAJzSABAHkAFgFssWgAJaw07QFkAEgC8QjEK3YBhQgFcmGHABMAqvy8LDooVjhoWB7cOKIEALQQ0PKomLgExJBkACzkcI4ihUA"Original Value": YCM0805F2SF‑801‑NWCM 2012F2SF-801-N800 Ohms @ 100 MHzhttps://www.digikey.gr/en/products/detail/tai-tech-advanced-electronics-co-ltd/WCM-2012F2SF-801-N/17835737?s=N4IgjCBcoEwwHABiqAxlAZgQwDYGcBTAGhAHsoBtEJRAAgHkALAWz1oAFaxE6BZACQBeIALokADgBcoIAMKkAruJwEAJgFUAdgEtJ9DLwJY8CgE4EQAXxIBaCNBDpI2fMTKUQAFnhgAbKMtAoACommon Mode Chokeshttps://www.digikey.gr/en/products/filter/common-mode-chokes/839Thanks for your time and for your reply.
Unknown smd sot23-6 switching regulator  - Page 1
Forum section: electronics / repair

author: wawinfo
author_rank: Contributor
timestamp: December 09, 2023, 03:13:14 pm
content: If anyone can help me find this unknown smd regulator? Any part number or datasheet needed, thanks a lot

author: gamalot
author_rank: Super Contributor
timestamp: December 09, 2023, 03:17:54 pm
content: https://www.richtek.com/assets/product_file/RT6212A=RT6212B/DS6212AB-08.pdf
Unknown smd transistor code - Page 1
Forum section: electronics / repair

author: wawinfo
author_rank: Contributor
timestamp: June 15, 2024, 01:39:48 pm
content: Hi, can anyone please help me to find this transistor with unknown code?

author: wawinfo
author_rank: Contributor
timestamp: June 15, 2024, 01:43:15 pm
content: Maybe it's useful to say that is used in c2960s-24tsl network switch from Cisco

author: RoGeorge
author_rank: Super Contributor
timestamp: June 17, 2024, 09:24:31 am
content: See if you are lucky and find it in one of these databases:https://smd.yooneed.one/http://markingcodes.com/search/

author: McMax
author_rank: Newbie
timestamp: June 17, 2024, 07:20:25 pm
content: recognizing a SOT-23 transistor from the top mark is not easy.If you have another one on the board and you're sure it's working you can desolder and measure it, then you can find a similar one. At the end, what you need to match it's just the Vce, the Hfe and the channel type.Do you know what is doing ? If it's used as a switch it's even easier...
unknown to92 transistor - Page 1
Forum section: electronics / repair

author: asp
author_rank: Regular Contributor
timestamp: April 09, 2025, 09:56:15 am
content: Hi guysCould anyone figure out what the transistor in the attachment actually is? I searched left and right but I cannot find anything.pin2 of this transistor is connected to OUT2 (pin7) of a TL072Thanks

author: joel16
author_rank: Contributor
timestamp: April 09, 2025, 03:34:11 pm
content: Are you sure it is a transistor? Can you measure to find base emitter junction?PH makes me think something Philips, but I had no luck finding anything close to this.

author: asp
author_rank: Regular Contributor
timestamp: April 09, 2025, 06:37:05 pm
content: In the end I did use a 2N3904 and that did the trick. It seems it's a NPN transistor, now I cannot be sure of its params but that 2N3904 did the trick for me (using the same pinout) so if somebody tries to search for that PH ON565C maybe this helps
Unknown vape inhaling sensor (MEMS?) - Page 1
Forum section: electronics / repair

author: Krotow
author_rank: Regular Contributor
timestamp: May 15, 2024, 01:57:04 pm
content: Coworker asked for help with Argus G vape pen he have. As he said, inhaling detection doesn't work anymore and now vaporization works only by pressing the button. During disassembly I found that inhaling sensing seems happen through little channel from mouthpiece side which ends inside tiny component with metalic cover, very similar to barometric pressure sensor, through tiny hole in PCB. Hole cleaning with isopropyl alcohol didn't helped. Seems vaping liquid through channel got inside sensor and caused it to fail. Removed it from board (it broke beyond recognition on that). From what I seen inside and PCB pad configuration it surprisingly look like MEMS microphone in phones. It might work like that, most likely inhaling is detected by voltage change in mic output. I foundthe article about MEMS tech in new vape penswhere component and its pads in picture also look like failed sensor that I removed from board. Do anybody know what and which this component really is? And where I can get it?Honestly turning vape pens into mini-smartphones seems utterly stupid idea (together with non-removable lithium batteries in these).
Unknown Variable Inductor? - Page 1
Forum section: electronics / repair

author: blizz
author_rank: Newbie
timestamp: March 04, 2022, 05:30:11 pm
content: I think these are variable inductors, I have a thousand that was going to list on EBay as NOS.Would like to be able to tell potential buyers something about them, maybe some kind of inductance value or range.They are about 5mm on a side.Couldn't find anything with google and the numbers. These probably date back to the 90'sAppreciate any info or suggestion someone could give.

author: KevinA
author_rank: Regular Contributor
timestamp: March 04, 2022, 06:12:59 pm
content: Go to the American Radio History website and download the Ambit International catalogue, which gives you the whole range of Toko inductors

author: blizz
author_rank: Newbie
timestamp: March 04, 2022, 10:22:20 pm
content: Cool! I'm a programmer so when I saw this in the catalog got excited. Started on a Billings, then CP/M machines moving onto Apple II IBM 370 and eventualy Unix and PCs. I remember when computers looked like this.Am not sure how to match up what I got with what is in the catalog. My numbers 5PLC-1427N and on the can 1427 7268. Maybe 27pF internal capacitance but am having difficulty matching up the other numbers. It's tons more than I knew about them just an hour ago though so that is SUPER!Thanks Kevin!!!
Unobtanium fuse - Page 1
Forum section: electronics / repair

author: PlainName
author_rank: Super Contributor
timestamp: April 26, 2021, 01:09:10 pm
content: I have a CCTV installation tester and one function is the ability to power the camera under test from the device. The output is specified as 12V 1A and in the dim past (this is many years old) I recall it powering cameras without issue. Then some while back it kind of didn't, in that sometimes it would work but other time the camera would repeatedly reset. It's not a feature I use that often, but it annoyed me enough yesterday that I resolved to fix it...So, in essence, there is a resettable fuse between the supply and output, as captured in the photo. If I put a load of 180mA or so on there, the output voltage drops to 10V, and then if I wind it up to a bit over 200mA the fuse trips. My cameras typically sink 180mA on power-up (winding the auto-focus in then out) and settle at about 80mA after that.Obviously the fuse is not up to spec, so I go looking for a replacement. However, it is 0805-sized and I can't find anything in that size with 12V 1A rating (or even close). Sure, I can go for 750mA but at 6V, or I can go for 15V but at 100mA. It's the classic two out of three thing.Am I missing something about the fuse spec, or have they pulled a fast one and ignored some aspect on the installed fuse?

author: wraper
author_rank: Unknown
timestamp: April 26, 2021, 01:30:08 pm
content: Quote from: dunkemhigh on April 26, 2021, 01:09:10 pmExcept it's 1206.

author: wraper
author_rank: Unknown
timestamp: April 26, 2021, 01:43:23 pm
content: Should be Polytronics (PTTC) SMD1206P075TF/13.2https://datasheet.lcsc.com/lcsc/2003112036_PTTC-Polytronics-Tech-SMD1206P150TFT_C495353.pdf0.75A hold current, 1.5A trip current, 13.2V VDC.

author: PlainName
author_rank: Super Contributor
timestamp: April 26, 2021, 01:55:06 pm
content: QuoteThat would explain a lot! Remeasuring, you are correct - I must've had a brainfart with the calipers.QuoteThanks very much
Unresponsive Fujifilm X-M1 Camera - Page 1
Forum section: electronics / repair

author: MattHollands
author_rank: Frequent Contributor
timestamp: April 04, 2021, 05:02:16 am
content: Hi,I recently bought this camera from Ebay -https://www.ebay.com/itm/Fujifilm-X-M1-MirrorLess-Body-16-3-MillionPixel-Aps-C-Silver-Broken-For-Parts-/303926982823?nma=true&si=y95Wbg5m1uCvDhVqCohAsAJBJ7k%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557- figured it could be a fun repair.I expected this to be a display issue - but it seems to be something very different. Firstly, the battery seems pretty dead and I don't have a charger for it, but I can shove 8V where the battery should be and it turns on "fine". Indeed, I see the blue dot on the screen as explained in the ebay listing. However, if I hold the "disp/back" button while turning it on, it enters firmware update mode and the screen turns on totally fine - lights up with a white image and some text. I decided to upgrade the firmware and I successfully did that from the SD card. So it seems the device has some brain activity and the display is fine. On top of this, if I connect via USB I can download images onto my computer. More indication that the brain is alive.So the only issue is that if I turn it on normally, rather than booting into some OS and showing me a menu, it just shows the blue dot. Pressing buttons and the shutter gives no indication of life. My best guess is that the is a loose connection inside and it gets stuck waiting for some part to respond - the sensor board maybe?I opened it up following the iFixit guide and reseated a few connectors and checked the main fuse - problem seems to remain. No guarantee I correctly reseated the connectors but at a first pass didn't seem to help.Any suggestions?! It seems strange that it can upgrade it's own firmware but it can't boot properly.
Unstable LCD image - Page 1
Forum section: electronics / repair

author: cosmarchy
author_rank: Contributor
timestamp: October 28, 2022, 09:08:16 pm
content: Hi,I have a LCD panel connected to a display controller which has a really unstable image. As I cannot see a way of attaching a video here, I've put it up on vimeo hereI've tried re-seating the rear connector and have the controller connected to a 12v 22A PSU so there is more than enough power.The problems are the same if I try the HDMI or DVI connectors and I've tried a number of different equipment all with differing severity of instability. The LCD panel came from a working laptop.Does anyone have any ideas as to what might be going on here and whether it is worth pursuing any further???Thanks
Upgrade Hacking - 1M 2M options - TDS500 TDS700 - Series C or D - Page 1
Forum section: electronics / repair

author: Tantratron
author_rank: Frequent Contributor
timestamp: February 16, 2021, 10:20:10 am
content: Hello, as it is known and experiment by different members, it is quite easy to upgrade via GPIB the SRAM acquisition A10 board from 1M or 2M options. Some of these A10 boards have already soldered the maximum SRAM storage memory so only by software we can manipulate or set which option: 50Ko standard or 500Ko (option 1M) or 8 Mo (option 2M).However after inspecting 6 different TDSxxx wether C serie or D serie, I have two technical questions.First here are the different SRAM models I've found so far within the TDS520D, TDS540C, TDS754D, TDS784C and TDS794D:AS7C164 (8K x 8bits) able to offer option 1MAS7C256 (32K x 8bits) but the two TDSxxx were set standard 50KIDT7124 (128K x 8 bits) able to offer option 2MQuestion 1: do you know if the oscilloscope will fail or brick or self-detect an issue when forcing option 2M (8Mo) but the SRAM total memory is able only to offer 50Ko or 500Ko storageQuestion 2: what is so particular with AS7C256 because I find strange the total memory (there are always 16 SRAMs per channel) offers 32K*16*4 = 2MoDoes this AS7C256 internal mapping hardware can only work with 50Ko option even though its storage is higher or is it OK to set at 500K (option 1M) without failure ?Thanks, Albert

author: madao
author_rank: Frequent Contributor
timestamp: February 16, 2021, 05:57:11 pm
content: I have repaired many TDS700/500.only old TDS540/520 has 8x 6116 SRAM per channel, if 1M option is ordered -> upgraded to 6264, swapping to 6264 is possible. (but CPU board must be also upgraded to 1M (few 62256 to 621024 swapped)TDS744/724A/754C has 8x 6264, indepent of 1M Option, it is up to 1M hackable. 2M Option requiered other acquisition board(swapping to bigger SRAM is not possible)TDS754D with old ACQusition has 16x IDT 71024 SRAM (128k x8), up to 2M hackable.TDS754D with new ACqusition has 8x MT58LC128K32 (128k x32 ) dito up to 2M.Greetingsmatt

author: lucasc
author_rank: Newbie
timestamp: July 12, 2025, 08:37:09 pm
content: Hi Matt,Do you have experience with the TDS794D? The one I've got seems to have all the memory chips, but only option M1 enabled. Do you know if that means it's possible to hack that one up to M2 by software only?Cheers!

author: madao
author_rank: Frequent Contributor
timestamp: July 13, 2025, 11:40:20 am
content: 2M option requires HD-optionThis fact, i didn't know at this time.
upgrading HP83620A to a HP83623A - Page 1
Forum section: electronics / repair

author: pe2ben
author_rank: Contributor
timestamp: January 30, 2024, 11:13:44 am
content: Hello everyone,Is it possible to upgrade a HP83620A to a HP83623A by only change the amplifier from a HP83623A?I only need the higher power for driving the MM source modules (HP8355xA series) so i need no external amplifier anymore. The MM sources need +17dBm as minimum input.Thanks, Ben
UPS APC replacement battery. - Page 1
Forum section: electronics / repair

author: KKTHUONG
author_rank: Newbie
timestamp: February 10, 2020, 08:24:37 am
content: Hi all.I have a UPS SURT15KRMXLI. It is broken battery. I have replaced 4 rows of UPS batteries = 32 batteries 12v-100AH. Ups still work normally. But the Run time of the UPS has not changed. Pls show me how to change the run time.

author: TheMG
author_rank: Frequent Contributor
timestamp: February 11, 2020, 02:11:43 am
content: On most APC UPS you have to do a "runtime calibration" from the monitoring software. This will cause the UPS to run the load on battery power to measure how much battery capacity it has available, thus resetting the runtime to a more accurate number for the new batteries.There is another method which is to reset the battery constant using a serial terminal program and entering the appropriate commands and value for the UPS model. I'm not sure for your specific UPS, I'm more familiar with the smaller units of the Smart-UPS lineup.

author: KKTHUONG
author_rank: Newbie
timestamp: February 11, 2020, 06:14:00 am
content: Hi The MG.I connected the serial cable. after I type on Hyperterminal when I press> it shows 004 when I press + it shows NO. Can you guide me to correct it?

author: EEEnthusiast
author_rank: Frequent Contributor
timestamp: February 11, 2020, 07:07:05 am
content: you could try out one thing. Allow a couple of full charge and discharge cycles. This may reset the battery model in the UPS to a higher capacity.

author: KKTHUONG
author_rank: Newbie
timestamp: February 12, 2020, 07:35:07 am
content: I will turn off AC input at 7h00Am Saturday. Hope Battery will High Capacity. Thank you very much.
UPS KONIG CMP-UPS2000 - Page 1
Forum section: electronics / repair

author: Yngve Fiskum
author_rank: Newbie
timestamp: September 07, 2024, 05:50:24 pm
content: Hello!I have a KONIG CMP-UPS2000.This unit was last used 10 years ago. Was working but had bad batteries. Those where remove before storage.Standard config is 4 x 7,2AH batteries in a 2S2P config. For testing I only have it with a 2S config.Only problem I have found so far was the header on the display board, for a cable coming from the transformer going into the display board. It was loose. So that is soldered in place, and "reinforced" with hot glue.And the cap hanging down from the display board is gonna be replaced when/if I get the unit working. Looks like it's starting bulge.Measured input voltage (on the board) is about 230V AC. Output voltage (on the board) is about 25V AC when there is no load. Drops if I try to power anything from the socket.Same measurements on mains or battery power.Display indicates 220V output.I can't seem to find any electical documentation either...Thanks- Yngve

author: Yngve Fiskum
author_rank: Newbie
timestamp: September 07, 2024, 09:52:17 pm
content: Looks like the voltage goes up after some time. Turned it on and let it sit about 10 minutes, and I get a reading of 56V AC.
UPS Liebert GXT2 700RT230 - Page 1
Forum section: electronics / repair

author: registraciy4444
author_rank: Newbie
timestamp: November 12, 2020, 06:35:59 am
content: Hello.UPS Liebert GXT2 700RT230.I need a diagram or names of parts Q5, Q6, Q7, R26, or photos of the board.The transistors were changing. Replacements may have been incorrectly selected.
UPS MGE ESV 22+ help - Page 1
Forum section: electronics / repair

author: Atanas79
author_rank: Newbie
timestamp: July 23, 2019, 05:05:58 am
content: HelloI have this ... but the batteries are external that are connected to a 9 pin Molex MLX socket. I need information about the socket diagram or circuit .Just i know - 48v DC ( from 8 x 6 V / 12 AH )There are 3 wires for the positive potential of the battery, 3 for the negative which are connected to the mos transistors.One wire to ground the battery. Two wires that go to the PCB electronics with which the board itself is powered.
UPS PSU power loss - Page 1
Forum section: electronics / repair

author: legsElectric
author_rank: Newbie
timestamp: November 07, 2024, 03:37:28 am
content: Hi allI've got a server-rack style PSU that powers a UPS on our 22kv switch gear, that has thrown up a rectifier fault and no longer puts out any DC voltage. It's not an expensive item but the lead time on a replacement is long so if there's any way to affect a repair it'd be a big win. I'm only a regular, albeit handsome and modest, sparky so my knowledge of it's inner workings are fairly limited. But I do have access to a electronics lab and some test gear so I'm hoping to do a miracle fix and look like a legend in the eyes of upper management.Current status is:-General FaultandRectifier Faultindicated by the UPS controller LEDs- Solid green Power LED (pg.10 of the attached manual) on the module front panel- Solid red Alarm LED on the module front panel, regardless of whether it's racked into the panel or sitting on the lab bench- 12Vdc cooling fan working- 0Vdc on the main output- no obvious damage or scorching, and the electrolytic caps aren't swollenI'm not sure where to go from here so I'm hoping for a bit of guidance. Thanks in advance!

author: u666sa
author_rank: Frequent Contributor
timestamp: November 07, 2024, 04:25:53 am
content: They are 100% repairable. Easy $50 to $150 I tell you, if you doing these repairs on regular, think $500 and up a day, free money.This particular cap looks bloated to my eye. Plus you saying rectifier fault, that means voltage isn't as straight as it should be. I say pull all 3 caps, check them, replace as needed. But in your case, since you don't have LCR meter, you just replace all 3 caps. Caps can have larger capacitance, just make sure voltage is at least that what those caps are and they fit in.Where to get caps? Here I have a store, I can run to it and buy caps. In larger city I would have pickup points for what is equivalent to digikey and farnell. Plus I could pick them in equivalent of amazon and have them delivered to pickup point for free. Your options depend on what is available in ausie land. Be careful with ali, sometimes large caps are fake, you open them up and inside is a small cap.

author: Poroit
author_rank: Frequent Contributor
timestamp: November 07, 2024, 06:31:57 am
content: G'day legsElectric,I have found the attached very useful when repairing SMPS.Haseeb Electronics also has a lot of helpful videos.Just be careful when you pull it apart that you sketch or photo where all the component insulators are mounted.Typically a multimeter and a ESR tester is all the test gear you need.I use Element 14 or RS in Oz for components.

author: legsElectric
author_rank: Newbie
timestamp: November 07, 2024, 08:03:31 am
content: Awesome, thanks a lot!Quote from: Poroit on November 07, 2024, 06:31:57 amThat's just the kind of thing I was looking for, a bit of light reading for the weekend hahaQuote from: u666sa on November 07, 2024, 04:25:53 amThere's a blob of silicone on that cap that probably makes it look that way but I'll pop them all off and check them over, thanks
UPS repair 9PX2200IRT3U - Page 1
Forum section: electronics / repair

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: December 13, 2024, 06:13:23 pm
content: Hi!I have bought the UPS in the title sometime ago and now its showing 'charger error' not allowing me power on the load.Now, before opening it up someone has maybe some schematics of the boards? Or a general advice when working out this specific problem?The batteries are ok, all in the range of 12.44V to 13.2V amd on the UPS board full voltage is shown ~77V so the battery pack seems to be working correctly.Thanks for helping me out!
UPS repair - Looking for schematics and suggestions - Page 1
Forum section: electronics / repair

author: AndersJ
author_rank: Frequent Contributor
timestamp: August 01, 2021, 10:17:14 am
content: The UPS will not start when the front panel button is pressed,The backligt turns on while button is pressed.The batteries are good.It has no model number or manufacurer id.Does anyone have:* A schematic digaram* Any ideas?Sorry about the image size and rotation, I cannot figure out how to fix it.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: August 01, 2021, 02:49:55 pm
content: Lawyers are hard at work to prevent schematics being released. DIY repairs are a big part of the reason.

author: geggi1
author_rank: Frequent Contributor
timestamp: August 01, 2021, 02:50:29 pm
content: How did the front crack?If it was dropped I would look for cracked solders and PCB.A quick google for Elrond i found a swedish page. From this I would assume that because of the only hit in google its probably a OEM product out of China.Sytart googling for combinations of kVA, Ah, battery size and so on. Google for pictures and you might find a UPS that looks similar.

author: AndersJ
author_rank: Frequent Contributor
timestamp: August 01, 2021, 03:26:54 pm
content: Good thinking about the cracks, and picture googling.I had not thought that far…Thanks.

author: nexus
author_rank: Regular Contributor
timestamp: August 02, 2021, 03:57:58 am
content: There must be a model # somewhere on the chassis or PCBs. Not like it would help, because this "ELROND" company is quite obscure online.Their full name is "elrond komponent AB". Apparently they have a linkedin page:https://www.linkedin.com/company/elrondOfficial website:https://elrond.se/produkter/typ/ups-1-och-3-fas/1-fas-ups/This product is probably obsolete. If you want to do component level repair, you need to carefully take it apart and start doing diagnostics at a board level. Checking power rails, inspecting for visual signs of damage. If you are not familiar with this process then this might not be a good first project, because hazardous voltages can exist inside of a device such as a UPS.

author: james_s
author_rank: Super Contributor
timestamp: August 02, 2021, 05:17:16 am
content: If you can't even find a model number good luck finding a schematic, it's hard to find schematics for even the name brand stuff although I have seen a few UPS schematics floating around. Is there something special about this specific unit? Decent quality UPS's can often be found very cheaply, needing only a new battery. It isn't worth spending much effort repairing one unless it's something fancy like a true-sine model.

author: fzabkar
author_rank: Super Contributor
timestamp: August 02, 2021, 11:24:45 pm
content: This company appears to manufacture Elrond's current UPS range:http://www.riello-ups.com
UPS Salicru SPS.500.ONE burnt resistor - Page 1
Forum section: electronics / repair

author: wcyb
author_rank: Newbie
timestamp: April 28, 2021, 08:36:13 pm
content: Hi everyone!I got a broken UPS (model and brand as per the post topic) and I have a problem.It seems that this UPS has been overloaded and several components have burned up - current measurement resistors, LM324 and one SMD resistor.While there was no problem with the first two components to fix it without a schematic, it was impossible to read the value from the burned up SMD resistor.It was labeled R13 and was located right next to the 0.1 Ohm resistors.Does anyone happen to have a schematic for this UPS or own the same model and can read the value of this resistor?

author: Manul
author_rank: Super Contributor
timestamp: April 28, 2021, 08:54:00 pm
content: Sorry, can not help, but some resistors in the circuit are not critical, or they can be calculated based on the circuit around. It is sometimes usefull to do a little reverse engineering, maybe you will find that you are lucky.

author: wcyb
author_rank: Newbie
timestamp: April 28, 2021, 09:08:11 pm
content: I thought about reverse engineering, but will leave that as a last resort.I'd rather fix it so it's like the original.We'll see how it goes.

author: wcyb
author_rank: Newbie
timestamp: November 19, 2022, 02:29:21 am
content: I found the correct value, so I'll leave the information here, maybe someday it will be useful to someone as well - R13 is 15k 1% 0402, but 0805 will also fit.The PCB is almost identical to the one used in the Legrand Keor Multiplug 800VA.
UR44 Audio Interface No Power - Page 1
Forum section: electronics / repair

author: young_silent_made_it
author_rank: Newbie
timestamp: December 07, 2023, 10:48:58 pm
content: I have a Steinberg UR44 audio interface that I had in storage for a few years, and now that I want to use it doesn't power on. I want to take this opportunity to learn electronics repair so I am trying to repair it for learning experience.I am looking for guidance on how to proceed with troubleshooting the problem.I have checked the original power supply with a multi meter and it works.I visually inspected the PCB board and don't see any issues, except what looks like a possible broken fuse but not sure. I checked it for continuity it reads 97 ohms, but 3 components that light up for a split second when I press the power button on the audio interface when I inspect the PCB board with a thermal camera.This pictures shows where the power jack is(blue circle), which is right next to the power button, and the barely visible green square shows the area where the 3 components are heating up/lighting up for a split second when inspected with the thermal camera.I am new to electronics repair, how should I proceed from here in troubleshooting the problem?Thanks for the help.

author: David_AVD
author_rank: Super Contributor
timestamp: December 08, 2023, 10:01:25 am
content: Maybe start by measuring all of the ceramic / MLCC SMD capacitors on the resistance range of your meter. See if there's any shorts (or reading of less than 100 Ohms) on any of them.
Urgent Help Please. - Page 1
Forum section: electronics / repair

author: Simon_RL
author_rank: Regular Contributor
timestamp: April 20, 2020, 11:57:43 am
content: Hi All,I stuffed the power switch on my oscilloscope (don’t ask, it was a case of stupidity) and I am trying to find a supplier in Australia. The switch (KDC-A11-2 DPST) is the same as the one in link below:https://www.ebay.com.au/itm/223956058510The switch is readily available in China, but I am looking at a minimum 2 month wait from China and I really can’t be without my scope that long. It will hold up my studies and a few projects I am working on.I have tried all the usual big suppliers, RS, Mouser, WES, etc, but not had any luck. If someone could please suggest an Australia Supplier or a suitable alternative available in Australia, I would be very grateful.Thanks in Advance.

author: AndyC_772
author_rank: Super Contributor
timestamp: April 20, 2020, 12:08:36 pm
content: Short the PCB traces together with a wire link, and put a piece of tape over the hole in the front panel as a reminder to keep your fingers out. The scope will work perfectly well, just turn it off by unplugging at the wall.In the meantime, order a new switch, and fit it when it eventually arrives. No hurry.

author: Simon_RL
author_rank: Regular Contributor
timestamp: April 20, 2020, 01:52:36 pm
content: Quote from: AndyC_772 on April 20, 2020, 12:08:36 pmThanks heaps Andy. I was thinking about doing that. After your comments and giving it some thought I will solder wire between the pins of what remains of the switch, which will be safer than just joining the wires. Also the powerboard all my important gear runs off has individual power switches for each socket, so that should work well.
Urgent to convert irreplaceable/unremovable battery type smartphone - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: March 31, 2022, 11:44:06 am
content: How do we convert irreplaceable/unremovable battery type smartphone to be the replaceable one with its connector replaced to be the standard that is used for replaceable battery type ones ?
USB-B powered audio interface, How to check data port with Multimeter - Page 1
Forum section: electronics / repair

author: mbarry2025
author_rank: Newbie
timestamp: August 16, 2025, 09:21:41 pm
content: Hi All, I have a Behringer404 audio interface. it’s USB-B powered, when I connect it to my pc via USB, the unit powers on, but the PC/ Behringer driver don’t recognize that the unit is connected. I’ve tried different cables and different computers even a Mac. same result.It seems that the Power on the USB port works, but How to test with a voltmeter if the data on this port is faulty?Thank you.

author: ledtester
author_rank: Super Contributor
timestamp: August 17, 2025, 06:38:15 am
content: Does the device show up in the Device Manager (on Windows)?https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/usbview#use-device-manager-to-display-usb-information

author: mbarry2025
author_rank: Newbie
timestamp: August 17, 2025, 01:22:06 pm
content: No it doesn't show up in device manager. I installed USBView, it doesn't show up there either.

author: ledtester
author_rank: Super Contributor
timestamp: August 17, 2025, 01:52:46 pm
content: Is this what the front looks like?(see attachment)If you run audio through it do any of the LEDs (like "signal" or "clip') light up?Unfortunately, if it doesn't show up in Device Manager there's probably not much you can do about it.

author: Potential Resistor
author_rank: Contributor
timestamp: August 17, 2025, 02:19:13 pm
content: I had a look around and found this information which may be of use to you:"Reports below can be confirmed. I updated my drivers for the UMC, and it underwent a catastrophic failure. The USB device can no longer be properly recognised."https://www.behringer.com/product/review.html?modelCode=0805-AATSo it looks like it may be a driver (software) issue and not the cable or hardware.
USB DAC not liking external speakers - Page 1
Forum section: electronics / repair

author: phaseform
author_rank: Regular Contributor
timestamp: May 04, 2020, 01:30:42 am
content: I have seemed to have fried a DAC by connecting a small speaker and Sennheiser wireless headphones (both powered by isolated supplies) to it (together through a 3.5mm Y splitter)..Not sure why this would happen?Just watching this videoEEVblog #279 - How NOT To Blow Up Your Oscilloscope!Can't see how I have an issue here..??

author: Manul
author_rank: Super Contributor
timestamp: May 04, 2020, 02:11:06 am
content: Well, I dont know, but isolated supplies are not totaly isolated, they have AC leakage through capacitance if output side is not grounded. Easy way to look for such things is with multimeter. You can measure AC voltage between your USB ground and speakers input jack. But even in cases of leakage, the current caused is usually very low, so it is not likely to damage things easy, but who knows. Measure and maybe it will get more clear.