hybridfree/eevblog-posts huggingface dataset:
Repair help:Agilent MSO7054A White screen - Page 1
Forum section: electronics / repair

author: windancer9880
author_rank: Newbie
timestamp: December 26, 2019, 08:02:36 am
content: One day I switched on my MSO7054A scope, the scope can not login with blank (white) screen. I can do nothing about it now. Anyone can help me?

author: kosomsk
author_rank: Regular Contributor
timestamp: December 26, 2019, 01:36:34 pm
content: Hi! Connect to terminal & see log

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: December 26, 2019, 07:23:58 pm
content: I don't think there will be anything to see, the processor is not running.

author: windancer9880
author_rank: Newbie
timestamp: December 27, 2019, 09:11:35 am
content: Hi, I am sorry that I don't understand what you said for I am a newbie.I connected the "probe comp" to another good scope with probe. Also no signal.Someone from another forum told me that it is cause by the firmware losing.His suggetion is to buy a new blank chip of flash(Spansion S29GL128N10TF101), then write the firmware to the new blank flash chip with flash programer.Now I got new blank flash chip and flash programer(ALL-100), but I have no firmware(binary) 。

author: windancer9880
author_rank: Newbie
timestamp: December 27, 2019, 09:13:30 am
content: Thank you for your reply. The repair expense of Keysight is so expensive. So I have to try to repair it myself.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 27, 2019, 09:15:27 am
content: Maybe Keysight could provide you this binary fileworth to ask them ?

author: windancer9880
author_rank: Newbie
timestamp: December 27, 2019, 09:25:54 am
content: Thank you for your reply. I tried but difficult. What they can said is please send your instrument to Keysight repair center for repair.

author: nctnico
author_rank: Super Contributor
timestamp: December 28, 2019, 01:29:38 am
content: I'd first check if all power supply rails are there. Looking for the console output is a second option to see what is working an what isn't.BTW looking at the picture I see something which could be a solder bridge between 2 pins at the bottom-left corner of the flash chip. It almost looks like someone has replaced this chip before. The joints don't look as nice compared to the other solder joints on the board.

author: sonja
author_rank: Newbie
timestamp: January 16, 2020, 05:32:05 pm
content: Hi there,I also experience the same issue with my Agilent DSO7054A. White/black screen and boot loop problem. In my case all power rails according to the service manual are present.I've read about the change of the flash chip in another thread. My problem is also that I couldn't find a binary to flash. Maybe it's possible to unzip the sys7000A.jzp with the tool provided in the MSO/DSO hacking thread and flash the resulting binary. But does this binary contain the bootloader?
Repair HP Agilent E3632A Power supply - Page 1
Forum section: electronics / repair

author: Karicas
author_rank: Newbie
timestamp: July 11, 2024, 11:11:06 am
content: Hy guys,Where can i find a replacement for the CPU and ASIC for this power supply?I found some videos with reparing the power supply with the same problem and i´m stuck in the processor.I already do the reset mod but no result.No disply at all.Regard´sRui Martins

author: m k
author_rank: Super Contributor
timestamp: July 16, 2024, 04:14:39 pm
content: Maybe earlier thread has something.https://www.eevblog.com/forum/repair/agilent-e3632a-repair-320485/
Repair HP ENVY Laptop 17-cg1008ca Motherboard GPT70 LA-J504P - Page 1
Forum section: electronics / repair

author: neoOpus
author_rank: Newbie
timestamp: May 31, 2024, 05:38:57 pm
content: Hi,I am looking for the schematic of this HP ENVY Laptop 17-cg1008ca Motherboard GPT70 LA-J504P or this component, PQB4 reference (Unable to read the text beyondP5)I also want to replace these two other parts on the same board, one labelled43t(if I am not reading it wrong) and another resistor labelled2R0.Furthermore, if someone with experience could tell me, why would this component burn in order to avoid this happening again?And I have a question about modding this mobo in order to have more VRAM, right now, it has two of this chipModel: H5GC8H24AJR-R2C Brand: Hynix Series:GDDR5 Capacity:8Gb Voltage:1.5VWhich equivalent to 2 GBytes and I want to replace them to get 4 GBytes (to make some AI models work on it).Thank you.

author: m k
author_rank: Super Contributor
timestamp: June 05, 2024, 04:04:41 pm
content: Burning 43t and 2R0 is most likely overcurrent.Three legs of 43t connected, so maybe a source.Maybe two different voltages through those two equal resistors.9538 seems to be a battery charger.

author: perieanuo
author_rank: Frequent Contributor
timestamp: June 05, 2024, 04:23:41 pm
content: intersil datasheet may help if you don't get the mobo schematics

author: fzabkar
author_rank: Super Contributor
timestamp: June 06, 2024, 02:13:50 am
content: https://au.mouser.com/datasheet/2/698/REN_isl9538b_SDS_20180302-1999784.pdf(ISL9538BH)https://assets.nexperia.com/documents/data-sheet/BAT54CW.pdf(43t = BAT54CW)8N = PNP digital transistor?P5 = NPN digital transistor?
Repair HP141T 8555A Advice needed - Page 1
Forum section: electronics / repair

author: LR
author_rank: Newbie
timestamp: August 26, 2021, 01:50:04 pm
content: Hello I am repairing the HP spectrum analyzer type 141T and the unit HP8555A.There were many defects in it but these have all been resolved. One problem remains and that is about 12 dB too low a reproduction.After several measurements, I think this error is in the 50 MHz AMPL ASSY A2A5 (HP 08555-60060).The input of this unit is a JFET (Q1) and 4 transistors (q2-q5) type 2N7179.In the service documentation (SERVICE SHEET 5) a number of voltages are specified with a tolerance of 0.1 V. The measured voltages at the JFET on the Source is 2V (must be 2.8V) and on the Drain 13.00V (must be 10.06V .Also all other voltages stated on the transistors Q2-Q5 are about 2 Volt higher on the Emtter and Base. The voltage on the Collector is good (19.9V).What is striking is that the JFET is very warm > 60 degrees.Unfortunately no AC gain value has been specified. I measure a gain on the first unit Q1-Q2 of 30 dB. The +15 dB and +5 dB circuit work well.Suspicious is of course the JFET but it is difficult to buy and very expensive. In order to have a better look at this 50 MHz Amply A2A5 and possibly replace parts, you should remove the PCB.The service documentation SERVICE SHEET 18 describes the REMOVEL AND REPLACEMENT PROCEDURE of the THIRD CONVERTER A2 . In order to remove the entire module housing and board A2A5, the wires at the bottom of the housing must be soldered loose.What is not clear to me is whether when removing the housing of A2A5 the connections A2C8, A2C10, A2C11, A2C12, A2C8 and A2C13 on the board are solder points or whether these are pin connectors.When I have removed the screws from the A2 board and removed the connection 50MHz input and the soldering to J4 and J2 I can not get the PCB out of the housing. The PCB remains attached to connections A2C8 to A2C13.So my questions are:1st Does anyone know if the JFET q1 gets that hot2nd Are the connections A2C8 to A2C13 solder joints or connectors.Thank you in advance for your response, best regards,L.R.
Repair / identifying RTX 2080 Ti graphics card Burnt component - Page 1
Forum section: electronics / repair

author: simoncana
author_rank: Newbie
timestamp: January 01, 2023, 12:36:35 am
content: Hi!My GTX 2080 ti has a burnt 5pin component, which i need help to identify what it is. I searched google for pictures to compare. And i Found this picture (blue arrow for my burnt component). from what i can see it is "VT F". no hits from google search.

author: simoncana
author_rank: Newbie
timestamp: January 01, 2023, 12:45:32 am
content: Here is a picture from my card, with burnt component

author: fzabkar
author_rank: Super Contributor
timestamp: January 01, 2023, 01:00:03 am
content: Could it be MC74VHC1GT08?MC74VHC1GT08, ON Semiconductor, single 2 input AND gate, marking VT:https://www.onsemi.com/pdf/datasheet/mc74vhc1g08-d.pdfhttps://www.aliexpress.com/item/1005004975667588.htmlhttps://ae01.alicdn.com/kf/S876402a6e9714b21ac5cd0c43ea3281ab/VTK-VT-New-Original-Chip-SOT353-MC74VHC1GT08DFT1G-MC74VHC1GT08DFT-MC74VHC1GT08-MC74VHC1-MC74.png(photo)

author: mon2
author_rank: Frequent Contributor
timestamp: January 01, 2023, 01:07:59 am
content: Review this thread,https://electronics.stackexchange.com/questions/563613/need-help-to-identify-smd-component-of-vga-adapter-msi-gtx1070

author: coromonadalix
author_rank: Super Contributor
timestamp: January 01, 2023, 02:43:04 am
content: And the question is : how did it bust ?

author: MathWizard
author_rank: Super Contributor
timestamp: January 05, 2023, 01:53:20 am
content: When I click on either picture I see the 2nd pic, can't see the 1 with arrows.

author: simoncana
author_rank: Newbie
timestamp: January 11, 2023, 02:14:54 am
content: Thank you!I found this - a bit cheaper - its the same right?https://no.rs-online.com/web/p/logic-gates/8063989

author: simoncana
author_rank: Newbie
timestamp: January 11, 2023, 02:17:18 am
content: I uploaded the picture again!its in my second post! Strange?? :sEDIT:I found my component, just ordered from aliexpress:https://www.aliexpress.com/item/1005004609900384.html?spm=a2g0o.productlist.main.5.2349520eZTc7w5&algo_pvid=38f82f93-982e-4b71-bc76-50b89d1b88f9&algo_exp_id=38f82f93-982e-4b71-bc76-50b89d1b88f9-2&pdp_ext_f=%7B"sku_id"%3A"12000029819046505"%7D&pdp_npi=2%40dis%21NOK%2111.12%2110.01%21%21%21%21%21%40211bf4c516754792051877970d0746%2112000029819046505%21sea&curPageLogUid=2fzpeYMKqzEs

author: simoncana
author_rank: Newbie
timestamp: February 16, 2024, 11:02:11 pm
content: I figured out it was a shortage on 3.3v rail - mostly caused by dead gpu core.. according to my research 90% chance the core is dead..

author: testpoint1
author_rank: Frequent Contributor
timestamp: February 17, 2024, 03:00:53 am
content: U49 is M74VHC1GT08DFT2G, a common element.
Repair inverter - Page 1
Forum section: electronics / repair

author: thinkpad4by3
author_rank: Newbie
timestamp: May 12, 2019, 01:25:10 am
content: I have an inverter from an old laptop(1994) that is dead. It fires up for a second and then quits while making a audible high pitched humming sound. There is no possible way for me to get a replacement inverter for this machine, it is not available. Where should I start? I know caps of this age go bad but there are two small electrolytics that looks fine and the rest are thin film/disc. I really don't want to LED mod it given its kind of a pain and I've tested the backlight bulb to be bright and crisp using another inverter.Images of the board here:https://imgur.com/gallery/hY6YHFLImages of the CCFL being "jumped" by another inverter:https://imgur.com/gallery/iv9ybtn

author: amyk
author_rank: Super Contributor
timestamp: May 12, 2019, 01:57:30 am
content: Quote from: thinkpad4by3 on May 12, 2019, 01:25:10 amElectrolytics can go bad (drying up) without any signs of trouble. That said, those are probably decoupling on the input so not too critical to operation.You can probably replace the inverter with anything that fits in the space and has the right input/output; modern laptop inverters are much smaller:https://www.amazon.com/Single-Inverter-Universal-Replacement-Backlight/dp/B00VR6T25U

author: wraper
author_rank: Unknown
timestamp: May 12, 2019, 02:23:36 am
content: Those caps won't bulge as they don't have vent on the top.

author: thinkpad4by3
author_rank: Newbie
timestamp: May 12, 2019, 03:35:41 am
content: So I should start by doing a recap?

author: amyk
author_rank: Super Contributor
timestamp: May 12, 2019, 04:26:56 am
content: Find a suitable cap and tack it across the existing one, if the problem goes away then you can remove the old one, but otherwise I suspect the caps aren't the cause here.

author: thinkpad4by3
author_rank: Newbie
timestamp: May 12, 2019, 01:24:48 pm
content: I have some caps I could tack on there. The only problem is the markings. One is 33/25 and the other is 100/10, is this 33uf 25V and 100uf 10V or the opposite way around?

author: PKTKS
author_rank: Super Contributor
timestamp: May 12, 2019, 01:53:57 pm
content: Quote from: thinkpad4by3 on May 12, 2019, 01:24:48 pmTake no chances. If the caps are badly marked or if theyhave just no marks (or vanished marks) - assume worstcase.Try first a couple of well known OVER RATED VOLTAGE onesI would try THT (w/leads) ELCOS which are by far muchbetter marked and have more optionsPaul

author: thinkpad4by3
author_rank: Newbie
timestamp: May 12, 2019, 02:03:04 pm
content: Oh sorry I meant the caps on the board are poorly marked. Now I can tell you that this is the low voltage side of the inverter so it probably 5V for most of that side of the board.The caps I have as spares are properly marked.

author: thinkpad4by3
author_rank: Newbie
timestamp: May 12, 2019, 07:50:34 pm
content: Replaced a capacitor and the inverter works perfectly now.
Repair Keithley 2100 - Page 1
Forum section: electronics / repair

author: we
author_rank: Newbie
timestamp: March 29, 2022, 08:06:42 am
content: Several Keithley 2100 showed start-up problems. It figured out, that the three 1000uF/16V electrolytic capacitors beside the transformer, brand "stone", failed. I replaced them with Kemet ESY108M016AH4AA and it works fine.

author: alm
author_rank: Super Contributor
timestamp: March 29, 2022, 10:45:45 am
content: So did replacing the cap fix them? No wonder a cap made out of stone fails 😁

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 29, 2022, 10:57:45 am
content: Quote from: we on March 29, 2022, 08:06:42 amThanks for the topic.I have a "Keithley" 2100 that's working for now, would be interested in the replaced capacitor positions for the future, if you noted them.

author: tooki
author_rank: Super Contributor
timestamp: March 29, 2022, 01:43:59 pm
content: Quote from: we on March 29, 2022, 08:06:42 amHonestly, I wonder whether the “stone” caps were original to begin with. I kinda doubt it. I think there’s a chance someone recapped the unit in the past, using cheap caps.

author: shakalnokturn
author_rank: Super Contributor
timestamp: March 29, 2022, 09:44:09 pm
content: Hard to say... I'd have to peep in mine and check. The 2100 isn't really a Keithley anyway, I think it's a rebrand of the ARRAY M3500A so who knows how much they spent on electrolytics.

author: Kleinstein
author_rank: Super Contributor
timestamp: March 29, 2022, 10:05:13 pm
content: Quote from: shakalnokturn on March 29, 2022, 09:44:09 pmThe circuit is still very similar to the older Keithley 2000 to a large part. So much that the service manual and plan can help in a repair.

author: alm
author_rank: Super Contributor
timestamp: March 29, 2022, 10:29:33 pm
content: It's interesting that the design is so similar if it's not a Keithley design. Did one of the Keithley designers move to Array? Or did Keithley give the design files to Array to design a successor?

author: tooki
author_rank: Super Contributor
timestamp: March 30, 2022, 01:55:22 am
content: Quote from: alm on March 29, 2022, 10:29:33 pmI wouldn’t call it a “successor” since it didn’t replace the 2000, but it’s eminently possible that they gave them the 2000 design and said “make a cheaper version”.

author: ee1993
author_rank: Newbie
timestamp: May 13, 2022, 08:28:40 pm
content: Thanks to this forum, I was able to repair my Keithley 2100. Replaced the three Stone brand 1000uF 16V electrolytics, but it still failed. Then checked the 460uF 35V in circuit and one was low (289uF). Replaced it and now the meter works fine. I probably should replace all the Stone caps but some are hard to get to.Thanks again.
Repair Keithley 2410 cannot source output voltage over 400 Volts - Page 1
Forum section: electronics / repair

author: anupong1983
author_rank: Contributor
timestamp: March 02, 2020, 03:22:05 pm
content: Hello,Does anyone can help or who has repaired the SMU KEITHLEY 2410 before?after setting source output voltage over 400V the DMM display and output always stated only 460V (see display picture).I found the Analog board was found defective, I've already replaced new power transistor and FET (see picture) but cannot fix the failure.Hope someone can share the idea and help me fix this failure soon.Thank you so much.

author: anupong1983
author_rank: Contributor
timestamp: March 02, 2020, 03:26:51 pm
content: more picture

author: goaty
author_rank: Regular Contributor
timestamp: March 04, 2020, 08:07:30 am
content: Did you measure the test points and supply rails ? The service manual has some information.My 2420 is still defective.

author: anupong1983
author_rank: Contributor
timestamp: March 27, 2020, 02:34:15 pm
content: Hello goaty,Yes I have done. All power supply rails look okay but some test point I don't have the reference values. I only referenced to the manual stated.Do you know the part number of VR220 and VR221 (zener diode)?These parts do not state on the part list.

author: goaty
author_rank: Regular Contributor
timestamp: February 02, 2021, 04:41:54 pm
content: Probably MMSZ5240
Repair kenwood ka-v9500 - Page 1
Forum section: electronics / repair

author: Kentakung1
author_rank: Newbie
timestamp: January 28, 2020, 11:23:14 am
content: Kenwood. Ka-v9500Not. SoundHow to fix it

author: Haenk
author_rank: Super Contributor
timestamp: January 28, 2020, 01:55:25 pm
content: Buy a new one?Honestly: What kind of error report is that, who do you expect to help you with such a generic description?
Repair Lifted Trace on GAC Speed Controller ESD-5111 - Page 1
Forum section: electronics / repair

author: dr00bie
author_rank: Newbie
timestamp: July 30, 2020, 03:00:04 am
content: A friend asked me to look at a faulty PCB from a piece of equipment that he uses for his business. He has been unable to find a replacement of the exact part. If you know of someone who might have a replacement, he is very interested in buying one if this cannot be fixed.The board is a Governors America Corp (GCA) ESD5551 Speed Controller and is used for a surplus US military generator. My searches for a schematic have been fruitless, the document I found for the ESD5550 series doesn't show the same part as this one.I opened the case and found that the board was coated in a very thick, soft conformal coating. Initial inspection showed that the coating had lifted and separated from one section of the bottom of the PCB. It appeared that the solder mask was damaged and part of the trace was darkened. I carefully removed the coating with a nylon spudger and the coating lifted almost all of the rest of the solder mask from the trace and actually lifted a large portion of the trace foil as well.The trace goes from one leg of a large resistor (unknown value at this time, have not desoldered yet) to 5 pins of a 54 pin Molex connector. The trace is complete as it goes under the connector, so I am unsure what the best fix would be.1) Remove the lifted foil and scrape the PCB and put in a copper jumper from the connector to the through hole pad.2) Superglue the lifted foil down, scrape and install copper jumper into damaged section where no foil is present.3) Something else?I have attached 4 images,1) Bottom: Showing lifted trace after coating was removed and affected pins on connector.2) Top: Top of board showing the affected pins on the solder-side of connector. At far left, you can see part of the resistor that is mentioned above.3) Conformal_connector: Initial view of conformal coating and connector.4) Conformal_Close: Closeup of initial view of conformal coating.Thanks!Drew

author: SMdude
author_rank: Frequent Contributor
timestamp: July 30, 2020, 01:24:23 pm
content: What does that trace hook up to off board? Something has shorted out for the trace to burn like that.As for the trace itself, I would probably just spray some conformal coating on it and keep it pressed to the board while the coating dries.
Repair log - Samsung Galaxy Watch Active2 power button not working - Page 1
Forum section: electronics / repair

author: Victorman222
author_rank: Regular Contributor
timestamp: September 08, 2024, 01:36:56 pm
content: My friend water damaged his samsung galaxy watch active 2. The symptoms - not working power button (was working erratically before stopped working altogether). Before sending it he shot a couple photos showing a weird green blob  on the flex cable connecting power button to board which promptly broke off  taking trace with it. Also corrosion was visible on solder joint of the flex cable.Then I got the watch in my hands. It disassembles easily with no glue and somewhat specific Y00 screwdriver. Sadly I didn't take photos of the disassembly but there are many nice guides with photos on the internet.First i tried to bridge the broken trace with a jumper . This didn't restore functionality of the button, since the pad was corroded. The flex cable could be lifted from the corroded pad - it was not soldered.The cable was desoldered and the pad exposed . With some careful scraping copper surface was revealed and the pad was tinned . While the cable was desoldered I decided to take a picture of its bottom  showing the corrosion.After the pad was tinned I ran a similar jumper, but this time reaching the pad . After reassembly the button worked.It would be interesting to hear what you think that green blob was and overall feedback is appreciated.

author: Koray
author_rank: Regular Contributor
timestamp: September 15, 2024, 06:12:14 am
content: Thanks for sharing. I think that green blob is copper oxide. There is a possibility that more elements were exposed to water and corroded on that circuit board. Especially BGA chips are critical. It would be a good practice to clean the board in pure IPA and then distilled water and pure IPA again and dry thoroughly. You should also use a good quality flux and soldering wick to prepare the area for fresh solder. There are lots of videos on that. The button side of the flex shows corrosion too. You should address all affected areas for longevity of the repair. Good luck! K.

author: nidlaX
author_rank: Frequent Contributor
timestamp: September 15, 2024, 09:56:02 am
content: Nice repair! Mine is corroded so badly, one of the spring contacts for the battery broke in half. Might have to give it another shot, it's sitting in a plastic bag somewhere in the house.
Repair Logitech Z906 speakers - Page 1
Forum section: electronics / repair

author: sks12
author_rank: Newbie
timestamp: February 12, 2015, 07:05:59 pm
content: Hi Experts,My logitech Z906 speakers have blown off due to some voltage fluctuations. I opened up the woofer and to my surprise found that something is burnt ( i don't know what it is called and so I have highlighted it in red). I am uploading the pictures. Please suggest me what was that thing that got blown off and how to get it repaired.Thanks,Saurav

author: KiKiHUN
author_rank: Newbie
timestamp: January 02, 2022, 06:40:05 pm
content: https://drive.google.com/drive/folders/1hneUEiCzSagL9xqY97EnEmZD2zfqwrbj?usp=sharing

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 02, 2022, 10:54:32 pm
content: Quote from: sks12 on February 12, 2015, 07:05:59 pmYou & we read R96. Resistor of the 96th, just replace temporarily with varistor, the variable one, to find the correct value by set it from the bigger value to less one
Repair NVIDIA GTX 1070 *need help identifying smd* - Page 1
Forum section: electronics / repair

author: baymax9966
author_rank: Newbie
timestamp: July 15, 2020, 03:52:28 pm
content: Hi All,I've been trying to get my video card repaired and stuck on this part/IC that I can't get my hands on, if any of you know please write a replyPS : the picture is not mine since my phone can't get it focus, mine was "7J3G" if that makes any differentthanks!!

author: gamalot
author_rank: Super Contributor
timestamp: July 15, 2020, 04:08:03 pm
content: Richtek RT8816B Dual-Phase PWM Controller with PWM-VID Referencehttps://datasheetspdf.com/pdf-file/1425667/Richtek/RT8816B/1

author: wraper
author_rank: Unknown
timestamp: July 15, 2020, 04:12:07 pm
content: It's a memory VRM controller. The last symbol varies. I never figured out what it is but it's pin compatible with uP1666Q (did not try to use it as replacement).These cards usually fail with RAM VRM high side Mosfet going short and most of the Ram chips going short after that. GPU usually seems to survive. VRM controller may or may not fail.

author: baymax9966
author_rank: Newbie
timestamp: July 16, 2020, 03:54:09 pm
content: Quote from: gamalot on July 15, 2020, 04:08:03 pmdoes the A and B version is the same thing? I can only find the RT8816A here atmQuote from: wraper on July 15, 2020, 04:12:07 pmthanks but I can't find uP1666Q here and have to order from aliexpress which will take forever to be delivered, so i'll go with the richtekI have some spare GPU that I can pull the VRAM from but i've never attempt to do BGA rework before since the only tool I have is just heatgun/blower

author: wraper
author_rank: Unknown
timestamp: July 16, 2020, 05:00:53 pm
content: Quote from: baymax9966 on July 16, 2020, 03:54:09 pmRT8816Bdatasheet says that marking is7J=and the last two symbols are a lot code. Listings selling RT8816AI found show IC with7J=as well. So I checked a datasheet of RT8816Ahttps://www.richtek.com/assets/product_file/RT8816A/DS8816A-05.pdfand yep, it's7J=as well. So likely it's RT8816Aon your graphics card to begin with. Also I did not find any differences in the datasheets whatsoever including specifications and application circuits, they seem to be exactly the same. So RT8816B could be simply a newer revision.

author: wraper
author_rank: Unknown
timestamp: July 16, 2020, 05:10:32 pm
content: Quote from: baymax9966 on July 16, 2020, 03:54:09 pmYou should measure resistance of RAM power rail to GND. IIRC it should be somewhere around 80 ohm or at least in about this ballpark. If VRM MOSFETS are removed (to prevent shorting to GND if they are faulty) and resistance is still very low, like in single digit Ohms or below, then either some of RAM or GPU should be bad.
Repair of a LED bar, help identifying IC - Page 1
Forum section: electronics / repair

author: Snake____1
author_rank: Contributor
timestamp: September 25, 2020, 10:48:05 pm
content: Hello,I am trying to repair a LED bar, but one of two LED buck converters have failed.I have worked my google fu, but cannot find anything on the markings of the IC. Is anyone able to identify the SOIC8 buck converter used to drive the LEDs?Markings are:TS18D1817

author: fzabkar
author_rank: Super Contributor
timestamp: September 25, 2020, 11:24:53 pm
content: "1817" appears to be a date code.This URL has a similar IC with a "1713" date code:http://lantorino.com/en/para-led-bar-5-djujmov/Can you trace out a circuit diagram for the IC? Does it have an integrated MOSFET?

author: Snake____1
author_rank: Contributor
timestamp: September 25, 2020, 11:51:18 pm
content: Quote from: fzabkar on September 25, 2020, 11:24:53 pmVery interesting. It has the exact same construction as mine, although mine has 42 LEDs. Where 18 are driven by one of the buck controllers and 24 are driven by the other.One bank is dead, the other one lights up. Switched over between the two controllers and the dead bank followed the controller.Interested if anyone knows of a replacement...

author: fzabkar
author_rank: Super Contributor
timestamp: September 26, 2020, 12:02:40 am
content: I was searching for a datasheet which contained "0.091". That appears to be the current sense resistor (on pin #5 ?). This turned up some Richtek and Powtech ICs.I'm wondering whether this design is another one of those where the Chinese have copied a popular IC. Can you at least identify the ground, Vcc and SW (inductor output) pins?

author: Snake____1
author_rank: Contributor
timestamp: September 26, 2020, 12:54:17 am
content: Quote from: fzabkar on September 26, 2020, 12:02:40 amAs far as I can see and measure:PAD and 5 is connected to the inductor. inductor to LED cathodes.6 to sense resistor. sense resistor to VSS.
Repair of a Pulse QS20.241 with D-Well (TM) MOSFET - Page 1
Forum section: electronics / repair

author: sixtimesseven
author_rank: Frequent Contributor
timestamp: July 11, 2021, 11:41:15 am
content: I have a 800W 24V industrial PSU from Pulse, Modell QS20.241 which stopped working after the machine attached to it was power washedI found that the intput fuse and one of the main switching mosfets was broken.The supply seems pretty nice, but the used D-Well branded mosfets which I've never heard before. Modell Number: D-Well 11N60TD2. The closest I found was the SVS11N60 which was not available so I tried some TK14E65W5,S1X instead.It works now so far that it switches on the secondary side and generates some output voltage (18V) and a Overcurrent error.My first and most obvious guess is that the mosfets not a good fit... However I cannot find the originals datasheet or a distributor. Is it just a rebranded mosfet? Or does someone have a source for it?Currentltly the PSU is back together but I will add some pictures when I open it up again.Thank you

author: perieanuo
author_rank: Frequent Contributor
timestamp: July 13, 2021, 03:31:04 pm
content: himosfet is not the only deceased member of the familynot worthing chasing for dead pwm ic and mosfets (i don't think it's only the mosfets to be replaced)regards
Repair of a Rohde & Schwarz power supply - Page 1
Forum section: electronics / repair

author: Supsnoopy66
author_rank: Newbie
timestamp: August 16, 2020, 02:26:22 pm
content: Hi all!I got myself a used Rohde Schwarz FSEA.The unit shuts down after 5 seconds indicating a PSU issue. I manage to force a startup but it appears that the 5.5V supply is only at around 2.5V. I tried removing modules but it doesn’t change.I therefore suspect that the psu is the culprit here.I was wondering:- Does anyone happen to have a schematic for the Ascom psu used by R&S in that generation of instruments? It’s quite packed in there but nothing obviously wrong at first glance- Did anyone face a similar issue? I found an evidence of a bad smd cap on the forum but mines seem ok so far.Thanks a lot for your help!Best,

author: fzabkar
author_rank: Super Contributor
timestamp: August 17, 2020, 12:55:10 am
content: I would spend the time to draw up a diagram for the "mid board".https://www.onsemi.com/pub/Collateral/UC3844-D.PDF
Repair of Acer H223HQ monitor. - Page 1
Forum section: electronics / repair

author: ZaXaZ
author_rank: Contributor
timestamp: May 31, 2016, 01:10:07 pm
content: My monitor keeps "rebooting" some times a lot sometimes not that many times. but i don't see anything screaming dead component on the power supply.i'm assuming its the power supply sins it's turning fully off and on, showing acer logo.Top of board[img=https://s33.postimg.org/l0sstlcy7/DSC00424.jpg]pictures uploadunderside of board[img=https://s33.postimg.org/kljp3gnz3/DSC00426.jpg]image hosting freeis it worth bothering with or just buy this replacement?eBay auction: #http://www.ebay.com/itm/New-LCD-Power-Supply-Board-Acer-4H-0K302-A02-NO-repair-KIT-/291776931669?hash=item43ef42a755:g:8wMAAOSwKIpWC8Fm

author: wraper
author_rank: Unknown
timestamp: May 31, 2016, 01:44:31 pm
content: Please explain what you mean by rebooting. Does it show splash screen on each "boot"?

author: ZaXaZ
author_rank: Contributor
timestamp: May 31, 2016, 08:54:52 pm
content: It atc as if i would turn if off, and on. but with no interaction from my side.

author: wraper
author_rank: Unknown
timestamp: May 31, 2016, 09:03:59 pm
content: Probably some of the few smallest electrolytic caps is faulty, however IMO it might be something as stupid as faulty power switch. Tact switches tend to become conductive between contacts and start acting weirdly. Try to disconnect the board with power switch and see if it stops switching off/on.

author: samnmax
author_rank: Regular Contributor
timestamp: June 01, 2016, 08:37:54 am
content: I have a Benq monitor with the same problem, sometimes it starts turning off and on without touching it.The issue is that they use an ADC pin in the microcontroller for all the buttons, using a resistive divider. With time, buttons become slightly conductive (in the order of kOhms), and this screws up the voltages read by the ADC, triggering spurious button presses. As wraper said, try disconnecting the button board to see if that's the problem.

author: ZaXaZ
author_rank: Contributor
timestamp: June 02, 2016, 07:45:49 am
content: Quote from: wraper on May 31, 2016, 09:03:59 pmSounds like a cheaper solution if it workswill try it out

author: Zorang
author_rank: Newbie
timestamp: February 21, 2021, 08:07:38 pm
content: I know that this topic was inactive for some time but it is spot on for my problem..Also have Acer H223HQ with random restart problem. It appears that faulty button board is cause of restarting. When I disconnect it, no more restarts.

author: wraper
author_rank: Unknown
timestamp: February 21, 2021, 08:17:16 pm
content: Quote from: Zorang on February 21, 2021, 08:07:38 pmReplaceallswitches on that board.

author: MathWizard
author_rank: Super Contributor
timestamp: February 22, 2021, 03:33:42 am
content: Quote from: samnmax on June 01, 2016, 08:37:54 amI'll have to remember that, so far I've not worked on the button area's of anything modern, and I have stuff junk parts like control pad's from TV's/printer's that are probably way more complicated than just a few push switches.
Repair of Agilent DSO1014A after failed software update - Page 1
Forum section: electronics / repair

author: Ulitos
author_rank: Newbie
timestamp: October 06, 2021, 05:40:35 pm
content: Hello everyone!I have bought a used Agilent DSO1014A scope on a local test equipment store. It was in perfect condition, like wasn't used at all.The only defect was a broken 50% trigger button.Really, i don't know why i opened the software version menu, where i have read "The latest version of DSO1000 Series scope firmware can be downloaded from blah-blah-blah link" and got an obsessive thought to update scope's firmware.I have opened that link, and, suddenly, really found software update 011.04.00.04.06 SP5 from 2015!After that, i downloaded that update file to flash-drive and, as described in scope instruction, updated scope's firmware. That was a terrible mistake.After reboot i saw that text in almost all menues dissapeared, or displayed incorrect, as you can see at picture.I have tried to change languages, update firmware again and again and nothing happen.Integrated help system works correct and display text well in all languages. All functions and measuerements still work as usual.Moreover, time to time scope doesn't start up properly and just light up some buttons, sometimes it freezes in random time.I have contacted Keysight support with that problem, and have a pretty long correspondence, but only answer to all my questions and suggestions was just "We tried to restore old firmware on fabric and failed - scope's system rejects old firmware update files. Your instrument is 12 years old and is out of date, please buy new one"On one local forum i found dude with similar problem - he got troubles with SDS scope after firmware update, and just flashed its memory with memory dump from another similar scope. Of course, he failed, as replaced factory calibration data of his scope with data from another scope.After reading story of his bindings, i found a plan, how to repair my scope:1. Collect some number of memory dumps from similar dso1014a scopes with old identical firmware.2. Compare all dumps in hex editor to found, where factory calibration data and serial number is.3. Merge calibration data from memory dump of my scope with old firmware from another scope's dump.4. Replace memory chip ( s29gl064n90tfi04 )in my scope to new one and flash it with new monster dump.5. Pray The Machine God.6. Turn scope on and see if it still work.7.8. PROFITSo, i ask your suggestions and help with my trouble.I hope, you will understand my not perfect english.
Repair of an Acer x551mav-hcl1201e with a jumpy display - Page 1
Forum section: electronics / repair

author: Therepairguytt
author_rank: Newbie
timestamp: September 18, 2019, 10:00:14 pm
content: Hi... i am new here and i have an acer x551mav-hcl1201e that has a jumpy display with lines but when connected to a monitor it shows fine. So i decided to replace the LVDS cable first but there are so many variations of it i need a little advise on which one to buy. I tried to google the number on the cable but i never get the exact one
Repair of an EG&G 5113 with stuck display + firmware upload [FIXED] - Page 1
Forum section: electronics / repair

author: _Wim_
author_rank: Super Contributor
timestamp: August 14, 2022, 04:08:56 am
content: Hi All,Yesterday I finally managed to repair my EG&G 5113 preamp, and figured I would make a short documentation what was wrong with it.Symptoms where as follows:- after boot-up, display is stuck on the display shown in the picture (unless buttons where pressed during power-on, then it was stuck on a different display used for encoder test purposes)Cause:- broken trace under the socket of the Dallas 1225 sram chipRepair however did take me quite a while, as this broken trace was not visible without removing the socket, and no schematics are available. I first replaced almost all the 74-series logic chips, the micro, the Dallas sram chip and eprom, and then convinced myself the firmware was corrupt (as it had a blank section in the middle of the filled area). The firmware was not available online, and Ametek asked 2500€ for a repair (as was not willing to provide a copy of the firmware). I basically had given up, but thanks to a forum member, I did receive a firmware copy. To my surprise & disappointment, this had the same blank section. It did gave me new courage to continue the repair, finally finding the broken trace.Attached is also the firmware, should anybody be looking for this in the future.

author: CorporateReference
author_rank: Contributor
timestamp: January 27, 2023, 04:14:40 pm
content: Great thank you for your contribution. Do you know what data is in the Dallas ram chip? Did you adjust any of the trimmers after all the part replacements?

author: _Wim_
author_rank: Super Contributor
timestamp: January 27, 2023, 06:59:27 pm
content: Quote from: CorporateReference on January 27, 2023, 04:14:40 pmI did not adjust any trimmers during the repair, as the issue was clearly digital in nature (I did chip power supply rails off coarse). All the parts I replaced were digital logic IC's, I stayed away from replacing any analog chips.I do not think there is any calibration data in the ram chip, as the image I received from another forum member was exactly my image. It seems like the dallas chip is only used to store the user settings and to buffer the text strings for the display.
Repair of an HP 3490A - Page 1
Forum section: electronics / repair

author: TSCOLAN
author_rank: Contributor
timestamp: August 15, 2023, 02:24:59 pm
content: I received an HP 3490 from ePay.It is in good cosmetic condition but with a problem with the display, which was clearly shown in the photos of the sale : only one digit is working and several decimal points are present.While testing it on arrival the working digit is changing as the sample rate light blinks. Better : when shorting the input it oscillate around zero. I was confident that the measuring part was working and the fault was in the display unit.I attached a logic analyser to the display connector and saw that the scanning of the digits was stuck at low for each of the three lines. The IC generating these signals is a 74161N.I removed it and replaced it by a 74LS161 and voilà ! It is working againThe only bad thing about this unit is thas it is missing both Ohms and AC Borards, so it can only do straight DC Volts measurements.Thomas
Repair of an LG split AC system indoor unit PCB  - Page 1
Forum section: electronics / repair

author: TRN
author_rank: Unknown
timestamp: February 01, 2025, 06:59:22 pm
content: I am trying to repair an LG split AC indoor unit, which does not start and gives a CH05 error code.This indicates an error in the communication between the outdoor and the indoor unit.The outdoor unit is fine, so the problem is the indoor PCB.The indoor unit is an LG PC09SQ NSJ (3SNM09JA2FA), and the PCB has the following type number: EAX35907219-1.2 (see photo1)I changed optocouplers ICO1X & ICO2X and the NPN transistor S9013 which drives optocoupler ICO2X (see photo2), but this did not remedy the fault.Does anybody have the schematics of this board, and is willing to share?Any other input/advise regarding troubleshooting, is also much appreciated.Thanks in advance

author: m k
author_rank: Super Contributor
timestamp: February 08, 2025, 07:20:28 am
content: Use schematics from something similar, that part is very likely very exact replicant.You're lucky since your machine has optos, others may be just divided voltages without any isolation.Follow the trace, there can still be a bus tranceiver ahead.You can also scope what happens, there should happen an initial check up data.
Repair of an MS9710B OPTICAL SPECTRUM ANALYZER - Page 1
Forum section: electronics / repair

author: lowtension
author_rank: Contributor
timestamp: May 12, 2017, 08:36:33 am
content: Hello,I have a MS9710B with a problem on self test Optical error :008 Grating Error, checked that the grating mirror rotates slowly on startup and stops giving this error.Where do I have to search for the fault ? is it an alighnment error or hardware fault ?Thanks

author: t_ryner
author_rank: Regular Contributor
timestamp: May 13, 2017, 12:02:20 pm
content: Make sure to check the fittings, screws, ETC on the motor. Any pictures would help. Does it work still after the error is resolved?

author: lowtension
author_rank: Contributor
timestamp: May 14, 2017, 07:34:20 am
content: Hello,I have checked, There are no mechanical problems, the large grating mirror is driven by a motor and coupled to a Canon KP-1M laser encoder, it seems that it does not lock to the correct postion on the power up sequence , possebly the encoder circuit is not working , I will now try to understaand how the encoder works and follow the lines to the board and check.

author: lowtension
author_rank: Contributor
timestamp: May 14, 2017, 02:05:36 pm
content: Some observations:1- When unit is off and giving little force by my finger to the grating mirror frame it rotates freely without any resitance .2 - When the instument powers up, after 2 sec. the grating mirror starts to rotate slowly in a constant speed and is very stiff for about 1 and a half revolution and then it stops in a locked/"braked" position giving the grating error code. The machine stays at this state until I switch it off, then the "brake" realeses .One intersting observation is that during the 2nd step when it starts to rotate for about 1 an a half revolution, if I force my finger on the mirror frame , it goes free from the locked state and the grating errors appears upp directly after that. So I suspect that the motor control is working , the encoder detects thatthe mirror is stuck by my finger and realeases the locked rotational state to relaes the mirror free giving the same error.also, if I unplug the encoder socket to the controll board and power upp, the mirror will try to rotate on start but in unlocked manner (swings a little and tatty) but stops directly giving the same error.It seems some how the encoder and the motor circuit works (?) but not 100% correct since it can not ock the mirror in the correct position.

author: lowtension
author_rank: Contributor
timestamp: May 15, 2017, 02:39:30 pm
content: Is there any other sensor that detects the corroect position of the grating mirror?Thanks

author: brunomp
author_rank: Newbie
timestamp: June 20, 2022, 02:44:35 pm
content: Hi, i have the same problem.Can you help me ?You repair your machine?thanks
Repair of an old battery charger/Jump starter - Page 1
Forum section: electronics / repair

author: Thelanie
author_rank: Newbie
timestamp: February 24, 2020, 10:15:31 am
content: Hello good people of the blog.My father is an old mechanic and he had an old battery charger/jump starter it has served him well for almost 30 years but it has now finally broken down, when i turn it on and start to charge a battery it works fine on the two lowest current settings but if you turn it up any higher it snaps the main fuse in the house.. So both me and my father suspect that maybe the inductor inside it is shorting out.. I never tried to repair anything like this or even tried to troubleshoot one of these big inductors so it is a bit scary, anyone got some advice or a place i could start maybe? I opened the thing and took some pictures and the inductor does indeed look burned..Any advice would be appreciated, thanks in advance!Best regards from Denmark!

author: Thelanie
author_rank: Newbie
timestamp: February 24, 2020, 10:16:30 am
content: One more picture of it

author: Thelanie
author_rank: Newbie
timestamp: February 24, 2020, 10:17:23 am
content: Two pictures of the inductor..

author: tautech
author_rank: Super Contributor
timestamp: February 24, 2020, 10:38:58 am
content: Quote from: Thelanie on February 24, 2020, 10:17:23 amWelcome to the forum.Yes that looks bad but needs testing with a DMM for shorts and such.You may need to rewind it so some useful info is here:https://ludens.cl/Electron/trafos/trafos.html

author: Haenk
author_rank: Super Contributor
timestamp: February 24, 2020, 11:07:08 am
content: A new charger with electronic control might be a much better choice (for battery health) than the oldschool timer method. I would not spend money on a new transformer (which probably is much more expensive than a new charger...)gammeldags is not always betterRetro-fitting might be an idea, if your father really wants to keep it for sentimental reason...

author: Thelanie
author_rank: Newbie
timestamp: February 24, 2020, 11:21:28 am
content: Quote from: tautech on February 24, 2020, 10:38:58 amThank you for the reply. i will try to look at the website you gave me.

author: Thelanie
author_rank: Newbie
timestamp: February 24, 2020, 11:25:20 am
content: Quote from: Haenk on February 24, 2020, 11:07:08 amWe have several smaller modern chargers to keep batteries from motorcycles and such healthy through the winther, we really more used it as a booster for when we had an older car or motorcycle that needed a little extra juice to start, we have a lot of old Honda GL1000/1100 and the starters on these machines are not always too good... And it was just handy to give them the last bit of powerBut thanks for the idea of some sort of retro fitting, i try to look into that aswell, and i know you are correct "Gammeldags" is not really always better.. but oh quality was just more of a thing before i think
Repair of Anritsu MS2667C - Page 1
Forum section: electronics / repair

author: NiaDebesis
author_rank: Frequent Contributor
timestamp: March 01, 2023, 06:00:05 pm
content: Hi,I bought this instrument in a non working state on ebay at 1k euro.The instrument powered on fine then it stop working and blown out the fuse, the the fuse was replaced and it blew again.Do you have any suggestions for now? The event is similar to when a RIFA cap go boom. I am consulting the service manual for now, waiting for the instrument to arrive.I am creating a post in advance so I can cover the repair in detail and ask for help

author: coromonadalix
author_rank: Super Contributor
timestamp: March 02, 2023, 05:21:05 pm
content: pls do not double post for the same equipment, since you need repairs ... or kill the otherhttps://www.eevblog.com/forum/testgear/did-i-pay-too-much/msg4731824/#msg4731824