hybridfree/eevblog-posts huggingface dataset:
IRF A-7550 Resurrection Challenge - Page 1
Forum section: electronics / repair

author: rjmusto
author_rank: Contributor
timestamp: December 04, 2020, 10:41:29 am
content: Hi All,Picked up one of these analysers on eBay.First run on the bench all looked pretty good. Only issue was a rather unresponsive keypad - it would only react after a long push on a button, but then react rapidly, making it very difficult to actually select anything.I read another post on here regarding a dead keypad and the battery on one of the digital boards. So opened her up and pulled out the board, but the battery looked (2.9v). So put it all back together.Next power on; loud crack from the rear and I now have a dead analyser. Sigh. My guess is a blown electrolytic in the PSU.So my only question so far is; has anybody else got experience in repairing one of these supplies? Any tips? Taking it apart is not straightforward, but my guess is removing the rear panel will give access to this area, but with everything fixed to everything else, it’s not really clear when to start.Wish me luck!Ralph

author: rjmusto
author_rank: Contributor
timestamp: December 05, 2020, 10:24:13 pm
content: Just in case it is useful to anybody..... my progress so far:Once I got stuck in, I found the PSU module was fairly easy to remove. Found the switching FET on the primary SMPS was s/c and the crack I heard was the sacrificial fuse destroying itself. So far I have not found a reason for it failing though.I’ve replaced it, but the supply does not run properly. I’m wondering now if the transformer has developed a shorted turn. Can’t find anything else faulty.Anybody know how to test for a shorted turn on an switch mode transformer?Ralph

author: bob91343
author_rank: Super Contributor
timestamp: January 02, 2022, 10:01:17 pm
content: Do you have the service manual for this unit? Mine needs some attention.Thanks, Bobbo91343@yahoo.com
IRFP450 Mosfet Mounting - Page 1
Forum section: electronics / repair

author: Poroit
author_rank: Frequent Contributor
timestamp: May 31, 2024, 06:55:30 am
content: Has anyone seen a Mosfet mounted like ?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 31, 2024, 09:11:38 am
content: Like what? I don't see any mounting at all... I see a loose part.Including crop for easier download:Tim

author: trobbins
author_rank: Frequent Contributor
timestamp: June 01, 2024, 01:40:23 am
content: That is using a thermal pad with internal screen. I recall them from decades ago for emi management of drain parasitic current due to capacitance coupling. I used it in a prototype for measuring waveforms and Lisn levels for Pspice simulations of SMPS emi.

author: Poroit
author_rank: Frequent Contributor
timestamp: June 02, 2024, 03:15:13 am
content: Cheers trobbins and thank you for clarifying

author: trobbins
author_rank: Frequent Contributor
timestamp: June 02, 2024, 04:40:37 am
content: SIL PAD Shield, p.70https://media.digikey.com/pdf/Data%20Sheets/Bergquist%20PDFs/Sil-Pad_Guide.pdf
IRG4PC50UD Alternative - Page 1
Forum section: electronics / repair

author: gnif
author_rank: Unknown
timestamp: January 30, 2022, 08:35:58 am
content: Hi All,I am looking for a modern alternative to the IRG4PC50UD to repair a UPS with a pair of these that have blown.https://cdn.datasheetspdf.com/pdf-down/G/4/P/G4PC50UD_InternationalRectifier.pdfThese parts are obsolete and the only place I can find them in on eBay and as such are quite likely fakes.This STGWA50M65DF2 looks to me like a viable alternative but I am not sure and the lead time on getting a couple is quite long:https://au.mouser.com/datasheet/2/389/dm00249585-1798696.pdfAny other suggestions would be appreciated.

author: capt bullshot
author_rank: Super Contributor
timestamp: January 30, 2022, 08:49:50 am
content: If this were for production, replacing of the IGBT would call for lengthy measurements to ensure the new IGBT would meet all specs of the product. Especially thermal behaviour and short circuit robustness.Anyway, if it's for a one off repair job, most probably any modern IGBT with same voltage rating and same (or not too much above) current rating should do the job. I'd check for total gate charge too, as this has influence on the gate driver speed and load. Should be in the same ballpark or better (lower).Modern (higher gen #) are less robust than the older ones, as the silicon die area decreases, so there's less thermal mass available for overload situations. I don't have the figures, but a viable approach on the safe side would be to select for a similar die size at the same voltage rating (this should result in higher current rating), still check for input capacitance and total gate charge to not increase too much.
Iron temp problem with 852D Station - Page 1
Forum section: electronics / repair

author: ROUGEXIII
author_rank: Newbie
timestamp: June 20, 2019, 06:04:02 pm
content: Hi,I buy this YiHUA 852D station (a clone I guess)https://www.amazon.fr/Mbuynow-R%C3%A9paration-Temp%C3%A9rature-Contr%C3%B4l%C3%A9e-Professionnel/dp/B074C7RYLTIf the hot air gun seems to work, I didn't arrive to solder with the Iron.After checking the real temperature, I understood why: the extremity of the Iron is a lot less hot than asked (see attachments)For 500°C asked (the maximum) to get 351°C...The heating element:The heating element with 400°C asked:I see many other buyer had the same issue in the comments,any chance this is repairable?Edit: Subsidiary question: you think it is possible to display the real temperature from the thermocouple on a small digit display (with an arduino if needed)?
Is a hakko 926 worth fixing  - Page 1
Forum section: electronics / repair

author: Jonathan Clark
author_rank: Newbie
timestamp: February 16, 2021, 06:20:20 am
content: I have a Hakko 926 I got free in non working condition. It powers on but doesn’t heat up and I was wondering if it’s even worth repairing? ? ? ? ? ? ? ? ? ? ? ? ?

author: perieanuo
author_rank: Frequent Contributor
timestamp: February 16, 2021, 06:29:05 am
content: find the problem, calculate the cost, conclusion.if you will have use for it, yes it worths repairing, the handle is cheap, the pcb is not so complicated to diagnose and spare parts are everywhere on this planet, I bet you can repair below 25 eurosis it ok for you, only you know it

author: Jonathan Clark
author_rank: Newbie
timestamp: February 16, 2021, 06:36:24 am
content: Im pretty sure the heating element is bad and hakko doesn’t sell replacement irons or elements anymore but I found some old stock elements for $35usd but I also found Chinese made replacement irons for $10. My main iron is a weller wes51 I got free at from the same place missing the iron but I got a genuine weller replacement for it since it’s a much newer iron, But I guess it never hurts to have a spare soldering iron even though I’m very much so a newbie to electronics.

author: perieanuo
author_rank: Frequent Contributor
timestamp: February 16, 2021, 07:53:40 am
content: so you can by only the heating bar, not the handle, costs lesscheck:https://www.manualslib.com/manual/502438/Hakko-Electronics-926.html?page=7#manual
Is it no harm to extend earth wire of CRT TV? - Page 1
Forum section: electronics / repair

author: bshi02
author_rank: Regular Contributor
timestamp: June 05, 2024, 04:02:56 pm
content: I want to extend earth wire of CRT TV which is shown in the orange circle of below screenshot.Because short earth wire always get in the way of measuring voltage beneath the PCB.So In order to ease measuring voltage beneath the PCB, I 'll cut earth wire in two wire and soldering each of them to a long wire which has specification of "60227-3 300/500V 60227 KS IEC 06 H05-V-K 75mm^2 SANG JIN 2024 RoHS/LF CE 70℃"By the way,Is it no harm to extend earth wire of CRT TV?

author: shakalnokturn
author_rank: Super Contributor
timestamp: June 05, 2024, 08:19:06 pm
content: No problem with that, insulate the link so it isn't floating around creating shorts once it's back in normal position.Forgetting to connect the ground tabs to the CRT braid can have disastrous effects on the electronics.
Is it okay that these pads are bridged? - Page 1
Forum section: electronics / repair

author: xgabrielx
author_rank: Newbie
timestamp: May 25, 2023, 01:08:17 pm
content: I'm replacing an FFC connector in a video camera and these two pads (center frame) developed a short that just won't go away. It looks for all the world to me, like it doesn't matter, and those pads are connected in the circuit anyways. But, I don't see how a permanent bridge could even happen unless there is copper under there and all that happened was the enamel got flaked off.Everything tells me it's fine to continue. But I thought I'd check, cus you never know when you're missing something. That's why you missed it!

author: Ranayna
author_rank: Super Contributor
timestamp: May 25, 2023, 01:37:17 pm
content: Are you talking about the two, somewhat mishandled, pads on the top row, number 6 and 7 from the right, not counting the single square pad?These look connected to me. They look like they are both connected to the same copper pour below the pads.

author: xgabrielx
author_rank: Newbie
timestamp: May 25, 2023, 04:19:56 pm
content: Yeah... Those. And yeah. They look connected to me, too. But working on this scale is new to me, so best to check. I'm used to bulky valve amps. I'll give it a rip. There are components under the board that are way too close though, so I'm going to have to heat from above. I guess I'll do one side at a time and use heat tape to protect the connector as well as I can. I wouldn't worry, but the "low melt" solder paste I have, isn't great, Strictly EBAY redistributor of bulk goods from China. Buying a new board is cheaper than any repair shop quoted me, so I lose nothing by trying, and gain nothing by not trying. I just wish everything was bigger!
Is it possible that this capacitor is the only issue?  - Page 1
Forum section: electronics / repair

author: Mo2024
author_rank: Newbie
timestamp: March 31, 2024, 05:10:34 pm
content: Hello EngineersI have a CISCO RV345P router, priced at $700, that suddenly stopped working. The power adapter seems to be okay and is delivering the correct amount of power, but the router itself won't power on. Upon opening the case, I noticed a capacitor that appears slightly bulged at the top. Do you think replacing this capacitor could resolve the issue, or might the problem be more complex, necessitating a new router?I'm not sure if I should invest in trying to prepare it or of I should get a new one. please advice, and thanks a lot.

author: kripton2035
author_rank: Super Contributor
timestamp: March 31, 2024, 05:26:20 pm
content: you should build yourself an esr meterthere are many to choose, see in my signature belowhere on the forum, the simple but effective ones made by jay_diddy are the most obvious to start with.then you can check the esr of this capacitor to see its health state.or simply replace it to see if the router starts again.but yes a simple capacitor with too high esr can stop a power supplyalthough most of the time some other component like a diode or transistor is also involved.

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 31, 2024, 05:33:22 pm
content: Lots of capacitors come that way from factory, nothing wrong with them.But you definitely want to test the capacitance.

author: Mo2024
author_rank: Newbie
timestamp: March 31, 2024, 05:56:54 pm
content: Thanks a lot @kripton2035I'll defensively check out your an esr meter design.

author: Mo2024
author_rank: Newbie
timestamp: March 31, 2024, 05:59:19 pm
content: Thank you @DavidAlfaI thought all capacitor comes with a flat backI'll check the capacitance.

author: Zoli
author_rank: Frequent Contributor
timestamp: March 31, 2024, 06:05:18 pm
content: Wild guesstimate(based on the capacitor rated voltage): the capacitor is in a POE circuit; if the router is supplied thru POE, then yes, change the capacitor, or maybe the whole module, if is possible.

author: DavidAlfa
author_rank: Super Contributor
timestamp: March 31, 2024, 06:25:43 pm
content: Quote from: Mo2024 on March 31, 2024, 05:59:19 pmUsually yes, but I've seen some SMD come that way straight out of the reel.But it very well could be a bad cap.

author: cruff
author_rank: Regular Contributor
timestamp: March 31, 2024, 09:26:28 pm
content: Smaller caps (10 µF or so) in the power up circuit can go bad and prevent power on. I've seen that in a few network switches from Dell and Cisco. See if there are any small electrolytic caps on the board too. They may not look bad physically but have failed anyway. As others suggest an ESR meter could be helpful.
Is it possible to crimp Molex Mini Spox without experience in crimping? - Page 1
Forum section: electronics / repair

author: M_a-r_k-u_s
author_rank: Newbie
timestamp: December 26, 2022, 04:11:16 pm
content: Hello everyone,I want to crimp cables (Molex Mini Spox) to repair a robot. Since I have no experience with crimping, I wanted to ask here if it is possible to do it successfully without having it done before. Because the crimping pliers from Molex costs 400 bugs or so and I don't want to waste the money. I just saw that Molex offers also pre-crimped cables, but to maximum length of 450mm, which is not enough.I have some links to the plier and socket in case you don't know Molex Mini-Spox:https://www.digikey.de/de/products/detail/molex/0008701040/259393https://www.digikey.de/de/products/detail/molex/0638281900/7400393Thank you,Markus

author: inse
author_rank: Super Contributor
timestamp: December 26, 2022, 04:18:58 pm
content: This is rather flimsy stuff.If you need proper strain relief I would recommend to extend pre- manufactured cables.

author: wraper
author_rank: Unknown
timestamp: December 26, 2022, 04:25:48 pm
content: You do not need experience for crimping. It's very easy do right if you have a proper tool. Just watch some video how it's done to be sure you do everything properly.

author: wraper
author_rank: Unknown
timestamp: December 26, 2022, 04:27:39 pm
content: Quote from: inse on December 26, 2022, 04:18:58 pmFrankly your post makes no sense, please elaborate.

author: inse
author_rank: Super Contributor
timestamp: December 26, 2022, 06:07:29 pm
content: The proper tool is €400, so soldering extensions to pre-manufactured cables makes probably more sense.As with hobby tools you will not get a reliable crimp.

author: tooki
author_rank: Super Contributor
timestamp: December 26, 2022, 06:31:15 pm
content: Quote from: M_a-r_k-u_s on December 26, 2022, 04:11:16 pmThe Mini-SPOX contact isn’t too demanding on the tool, compared to some connector types. The ~$25 Toozo TZ-4228B (aka SN-4228B, etc) from aliexpress does a pretty good job on it. (I just tested it, using the second-smallest die opening, and it came out quite well, fits into the housing, and seems to pass an unscientific pull test.)Molex sells a cheaper crimp tool, thehttps://www.molex.com/molex/products/part-detail/application_toolin/0640160201which is officially for the Mini-SPOX (among others) that costs about $150 on Digi-Key. We got one at my old job and weren’t super impressed by it, but Digi-Key refunded the money (without even wanting the product back!) without any questions, so it’s something you could try out. Maybe you’ll receive one that was a bit better than what we got. But the $400 tools are much, much easier to use.You could consider buying pre-crimped leads and extending them with soldered splices.

author: Ian.M
author_rank: Super Contributor
timestamp: December 26, 2022, 06:58:19 pm
content: Tooki has put more effort into testing crimpers than many hobby users have into using them! See:https://www.eevblog.com/forum/reviews/affordable-crimp-tools-for-small-connectors-(dupont-etc-)/
is it possible to identify a figure out the value of a blown psu zener diode? - Page 1
Forum section: electronics / repair

author: mj148
author_rank: Newbie
timestamp: March 19, 2022, 03:33:13 pm
content: hey eevblog people,I have an old sony video-8 ev-s1 here that belongs to an elderly neighbour and it has a dead power supply, i've tried to find schematics or any data / pictures to help online but nothing useful so far.The unit has sentimental value to the neighbour and he would like to see it up and running again if possible.Anyhow, apart from the leaky capacitors that have ate away some of the board I can identify all the components and should have suitable substations for testing except for a zener diode that goes across the secondary of the transformer, it was burned in half so identifying it is out of the question, I assume it is a zener as the silkscreen on the pcb is a diode symbol with diagonal arms. (It runs from just below pin 7 of the transformer in the attached image)I'd like to try and get the powersupply up and running so I can see if the actual VCR part of the deck is still functional, usually for something important i'd try and track down another identical unit to compare / swap the part or take measurements but even that is proving difficult.So what i'd like to know is if there is some kind of power supply theory that will allow me to make an educated guess at what value diode was in there?thanks in advance for any pointers

author: fzabkar
author_rank: Super Contributor
timestamp: March 19, 2022, 04:03:33 pm
content: What is the voltage rating of C1? That should be the upper limit for the zener voltage. Allow for a 50% margin.

author: mj148
author_rank: Newbie
timestamp: March 20, 2022, 02:18:55 am
content: Hey thank you!Ahh.. I think I understand.. those two were the leaky capacitors 16v 2220uf..So 50% over or under margin? ie.. 20v-ish?Many thanks.

author: fzabkar
author_rank: Super Contributor
timestamp: March 20, 2022, 02:33:14 am
content: Quote from: mj148 on March 20, 2022, 02:18:55 amSince the capacitor is 16V, it must never see more than 16V in normal operation. Typically a designer will overrate a capacitor by 50% - 100%.Therefore a likely operating voltage would be 9V or 12V. That would be the zener voltage.If this is a regulated DC supply rail, try to determine which ICs are connected to this supply by performing a continuity test with your DMM. Then look up the datasheets for these ICs.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: March 20, 2022, 09:48:48 am
content: If manual or schematic on hand in such it might give T Volt info , or could meter, acquire V of sec. pin 7 - 6 less ~ 1 V (D dropped V)
Is it possible to repair a photo diode with lost terminals? - Page 1
Forum section: electronics / repair

author: bypassrestrictions
author_rank: Contributor
timestamp: January 27, 2022, 06:07:47 pm
content: Is it possible to repair a photo diode with lost terminals? There are no terminals on the photo diode, is there a way to repair it?

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 28, 2022, 12:28:35 am
content: nearly absolutely nodetach & put the in-tolerate replacement

author: EE-digger
author_rank: Frequent Contributor
timestamp: January 28, 2022, 01:25:06 am
content: If it is of low value, you can try filing or grinding the broken lead down to the package, then carefully flux and attach very small wire (like 40ga magnet wire).If it is of high value, sort of the same thing but have a small wire laser welded to the "stump". Laser welding induces no currents and will not damage the detector.
Is it practical to repair this monitor (Philips 436M6VBPAB)? - Page 1
Forum section: electronics / repair

author: Legion
author_rank: Frequent Contributor
timestamp: March 15, 2021, 12:59:30 pm
content: I have a Philips 436M6VBPAB. The diffusers that sit over top of the LED backlights are falling off. I can hear them rattling around in the chassis. Wherever they have fallen off I have bright plumes on screen. I've never taken apart a monitor before and I'm wondering if it's worth attempting the repair. My main concern is whether or not I'll have to peel apart adhered layers to get at the diffusers/backlight.Just wondering if anyone has attempted a repair like this on a monitor before and what I would have in store for myself if I attempted it?

author: tszaboo
author_rank: Super Contributor
timestamp: March 15, 2021, 01:04:24 pm
content: Its an edge backlight monitor. You will probably have an LED strip on the bottom, and there will be a bunch of lens on them, connecting it to the diffuser layer. I dont think you will need to peel off anything to fix it. Basically the panel likely can stay in one piece.Besides, what do you have to loose, other than your time?

author: SilverSolder
author_rank: Super Contributor
timestamp: March 15, 2021, 04:55:27 pm
content: You have nothing to lose - Don't turn it on, take it apart!

author: Legion
author_rank: Frequent Contributor
timestamp: March 15, 2021, 05:39:34 pm
content: I don't have a backup monitor, so I have to be careful.I'm also not sure it's edge lit, I have blooms across my screen at a spacing that suggests 5 rows by 5 columns.

author: tszaboo
author_rank: Super Contributor
timestamp: March 15, 2021, 05:44:41 pm
content: Quote from: Legion on March 15, 2021, 05:39:34 pmhttps://www.rtings.com/monitor/reviews/philips/momentum-436m6vbpabQuote

author: Legion
author_rank: Frequent Contributor
timestamp: March 15, 2021, 05:55:01 pm
content: Quote from: NANDBlog on March 15, 2021, 05:44:41 pmYeah, I saw that too, but what I'm seeing on my screen suggests otherwise unless the diffuser is able to take edge LEDs and focus their light at arbitrary points in the middle of the screen.

author: tszaboo
author_rank: Super Contributor
timestamp: March 15, 2021, 06:09:47 pm
content: Quote from: Legion on March 15, 2021, 05:55:01 pmYes, that is possible. Usually done in the diffuser plates. They are a sort of 2D light pipes.
Is my resistor damaged? - Page 1
Forum section: electronics / repair

author: nmoore
author_rank: Newbie
timestamp: January 30, 2024, 03:23:51 pm
content: Can someone please assist in telling me if my 20Mohm resistor is damaged? My circuit isn't working as it should but I noticed the resistor I-V curve looks weird on the component tester of my oscilloscope (see attachment)

author: Haenk
author_rank: Super Contributor
timestamp: January 30, 2024, 03:57:03 pm
content: You did not curve trace it in circuit, did you?

author: nmoore
author_rank: Newbie
timestamp: January 31, 2024, 01:45:50 pm
content: Quote from: Haenk on January 30, 2024, 03:57:03 pmNo I did not.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 31, 2024, 04:09:22 pm
content: Does the "flat-line then slope" changes into a "slope then flat-line" when the resistor is reversed in the curve tracer?- If not, I would suspect a malfunction in the curve tracer.- If yes, then the resistor indeed behaves differently with the voltage polarity, almost like a diode.I've read some oxide to metal contacts can act as a diode junction, so a high value resistor acting as a diode might be plausible.

author: nmoore
author_rank: Newbie
timestamp: January 31, 2024, 06:29:09 pm
content: When I reverse the resistor the flat line does change. Thank you for your reply
Is the problem in the oscilloscope UPO2102E that the program does not come up? - Page 1
Forum section: electronics / repair

author: azemati
author_rank: Contributor
timestamp: November 12, 2022, 12:04:36 pm
content: Hi everyoneI have an oscilloscope UPO2102E that I just bought, but unfortunately, when I turn it on, it says system loading...I searched on the internet and did not find a firmware programIf anyone has experience with this device, please guide me to fix it.Thanks a lot

author: ingalopez
author_rank: Contributor
timestamp: November 14, 2022, 09:18:46 pm
content: Looks like something is preventing the processor to finish the OS loading, or some initial testing.The only advice I can give is, first things first.Check the power supply voltages and their ripple, since bad electrolytics account for most of the problems. Inspect carefully the PCB for leaking caps and overheated components.

author: azemati
author_rank: Contributor
timestamp: November 20, 2022, 12:21:49 pm
content: I checked, considering that this device is new, this problem has been observed in this series of Uni-T oscilloscopes, and the main problem is in the micro processor.
Is the SENCORE Tube Chart WRONG? - Page 1
Forum section: electronics / repair

author: Voxman
author_rank: Contributor
timestamp: December 21, 2023, 07:48:06 pm
content: Hi Everyone!I'm working on a vintage Ampeg V4 bass amp head that unbelievably someone threw away. I haven't tested it under power yet but pulled all the tubes and tested them on my ancient Sencor Mighty Mite TC136 Tube Checker.And that's the reason I'm posting this on forum website. I've identified all the tubes and checked all of them. I'm a little stumped about one particular tube that the Sencore tube chart seems to be wrong for the 6K11/6Q11. It's a short stubby 12 pin keyed tube (I've never seen before but does belong in the amp).When I say keyed, it is minus one pin which should be inserted in only one way into a keyed tube socket. Sencore tube chart tells me it belongs in socket #10 which is NOT a keyed socket and will not fit in any way shape or form. It does fit in the #9 tube socket and that is what I used to test this tube. And it passed all tests.My question is : did Sencore make an error with misprint? Can I trust that only the tube socket # is wrong and all the other test criteria is accurate? Can anyone confirm this anomaly?Hope someone can cast some light on this issue and advise me one way or the other.Thanks for taking a look and comments.GARYI'm working on photos but they appear to be too large to include. I'm not sure how I can reduce the size using my iPad. Bummer! Please advise on THIS ISSUE!!!!

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: December 21, 2023, 08:34:50 pm
content: You can try looking at the pin connections underneath the chassis and seeing which pin correlated with which. Use that to make an educated guess weather if the tube belongs there or not.For an example, is pin 1 and 12 of a socket connected to a 6.3v AC tap on the transformer? Do pins 2, 5, and 10 connect to a B+ in some way?Use this knowledge and your knowledge of the pinout of the 6K11/6Q11 tube to judge if it belongs in the socket.

author: Voxman
author_rank: Contributor
timestamp: December 21, 2023, 08:58:21 pm
content: Hey thanks for commenting and advice!I just was able to upload photos so that might be useful in figuring out what if anything is odd.Thanks!Gary

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 24, 2023, 05:37:53 pm
content: Must be a typo. Socket 10 looks like loctal maybe? The 6K11 is a "Compactron", a later development from when tubes were trying to compete with transistors, mostly used in color TVs I think.
Is there a forum for Samsung TV repairs, or TV repairs in general? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: October 18, 2018, 08:05:46 am
content: Is there anyplace better than here where TV repair folks hang out? Thanks...

author: alpher
author_rank: Frequent Contributor
timestamp: October 18, 2018, 05:05:55 pm
content: You may try :https://www.eserviceinfo.com/for samsung specific stuff :https://www.samygo.tv/

author: retiredcaps
author_rank: Super Contributor
timestamp: October 19, 2018, 05:58:25 am
content: Tryhttps://www.badcaps.net/forum/.Originally it started as a place to replace bad capacitors, but morphed into TV repairs. Budm is your resident in house expert who helps everyone.I used to participate there a lot, but a lot of people want handholding and do zero to no research before asking anything.If your Samsung is an LED TV, the fix is likely simple, but time consuming.

author: smishra9909
author_rank: Newbie
timestamp: December 29, 2024, 06:18:45 pm
content: if you are facing issues with your tv you can take help herehttps://ravielectronics.in/for any type of issues you are facing with your tv.
Is there a way to check if a UV sensor is working or not? - Page 1
Forum section: electronics / repair

author: bypassrestrictions
author_rank: Contributor
timestamp: January 26, 2022, 04:33:28 pm
content: The UV sensor appears to have a glass over it, I couldn't see clearly but it appeared like there is a thin crack is on the glass, inside the glass I can see a squiggly trace. Two wires from this go to a 6-pin wire connector, I cannot detach those wires and I cannot desolder the UV sensor, the only option is I have to cut the wires, Is there a way to check if this UV sensor is working or not?

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 26, 2022, 05:56:50 pm
content: Deuterium-Lamp may be directed to UV sensor at varying distances which vary and depends upon the specific model of UV sensor) and try to read the current through UV sensor, then a resistor in series with the UV sensor with voltage to let it operate.So might get idea of the values and get from it the outline circuits schematichttps://molight-led.en.made-in-china.com/product/UwqAldFuMPkS/China-Jinke-UV-759-L5s-L6s-L7-L8-L9-UV-Spectrophotometer-Deuterium-Lamp-Dd2-5tz.html
is there an "easy" way to find a compatible buck regulator to replace one ... - Page 1
Forum section: electronics / repair

author: saronno
author_rank: Regular Contributor
timestamp: April 14, 2021, 10:04:16 pm
content: ... hard to find (at least here in europe)?The chip I need is a RT8125DGQW from richtek, but it seems I can get one only from china (and it take weeks if you dont' want to spendea fortune for the shipping).There is a lot of PWM buck regulator from ST, renases, intersil, etc .... but I just can't find one of the same pinout.Richtek has a page where you can find their counterpart for other companies regulator. But what I need was the other way around.Any idea??

author: ledtester
author_rank: Super Contributor
timestamp: April 14, 2021, 11:51:39 pm
content: Do you need one with a compatible pinout?Otherwise I'd perform a parametric search, e.g.https://www.ti.com/power-management/non-isolated-dc-dc-switching-regulators/step-down-buck/products.htmlfor TI products.

author: saronno
author_rank: Regular Contributor
timestamp: April 15, 2021, 07:40:04 am
content: Yes, I need one with the same pinout ... I am repairing a graphics card with no memory voltage ... this chipis the one who manage that voltage and of course it was shorted.

author: saronno
author_rank: Regular Contributor
timestamp: April 17, 2021, 11:49:20 am
content: APW8723 looks promising ... what do you think?http://www.datasheet.hk/view_online.php?id=2066143&file=0534%5Capw8723_7855278.pdf
Is there anybody/anyplace willing to reflow/reball a couple of BGA parts for $$  - Page 1
Forum section: electronics / repair

author: ArcticGeek
author_rank: Regular Contributor
timestamp: September 11, 2025, 02:56:04 pm
content: In reference to this thread that I started a while ago:https://www.eevblog.com/forum/repair/tektronix-dpo4034-acquisition-failure-but-works-fine-when-warmed-up/I have narrowed my failure down to what I suspect is inadequate soldering of 1 or 2 BGA ICs. I would like to have one or the other of these parts reflowed (and maybe reballed) to potentially fix the problem.Does anyone have the capability to do this or know of someplace here in the USA that will do this for a modest fee? I'm willing to spend ~$200 or so (or maybe a bit more) to get this work done. I emailed one place I found on the web and they quoted me nearly $4k....thats way too much.I can pay by paypal if desired, and I would accept the risk that the scope might not be fixed after the repair.

author: Haenk
author_rank: Super Contributor
timestamp: September 11, 2025, 03:28:41 pm
content: Quote from: ArcticGeek on September 11, 2025, 02:56:04 pmDid not check the manual for an overview, but U350 looks like some wicked custom hybrid module, using PCB material. I would assume these are almost impossible to work on. Probably needs something like a ZEVAC with known temperature curves to not damage the part when removing/soldering. *If* that part is even qualified for being re-used (which I doubt).Someone who is able to perform this service, will probably put a mild smile on his face, while kicking you out of office when being offered USD200 for that specialist work.If the device is not running correctly anyway, consider it being junk, and take desperate measures - like asking a local smartphone repairshop to reflow the chip. That will *maybe* work for a while.

author: daisizhou
author_rank: Super Contributor
timestamp: September 11, 2025, 11:16:47 pm
content: Quote from: ArcticGeek on September 11, 2025, 02:56:04 pmIf you can send the PCB to China, I will solder it for you for free, I have a BGA soldering machine,In my opinion it is easy, just add a little soldering oil and run a soldering curve with a BGA soldering machine.Even if I need to remake the solder beads, it is easy for meThe main issues are shipping costs and whether there are reliable testing methods (to increase the success rate)

author: J-R
author_rank: Super Contributor
timestamp: September 12, 2025, 06:03:16 am
content: Not sure why we need a new thread for this, in the same channel, but too late now, I suppose.You could check with this guy:https://www.youtube.com/@northwestrepairhttps://northwestrepair.com

author: ArcticGeek
author_rank: Regular Contributor
timestamp: September 12, 2025, 02:19:52 pm
content: @Daisizhou Thank you for the very generous offer. I'm not sure it will work out with all the shipping costs and customs issues, but I will look into it.I will send you a private message.Best,
Is there solder holder to be over a station iron handle - Page 1
Forum section: electronics / repair

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 26, 2023, 12:15:56 am
content: Any solder holder (just like one at an iron gun product) to hold the solder roll being able to be mounted over a plain station iron handle ?or one has made it up successfully innovatively ?

author: Kim Christensen
author_rank: Super Contributor
timestamp: January 26, 2023, 03:31:57 am
content: I highly doubt it since most people feed the solder with their other hand while soldering. Plus the bulk and weight of a solder roll added to the iron would be really annoying and inconvenient.

author: Swainster
author_rank: Frequent Contributor
timestamp: January 26, 2023, 04:00:01 am
content: Weller have (had?) an automatic solder feeder for production line use, however the heavy roll of solder is not mounted on top of the solder pen as that would indeed be pretty annoying. Instead the solder is mounted in the base and presumably uses something like a mig welder (or FDM printer, if you prefer) style feeder system. To be honest, it still looks rather unwieldy.
Is this a Fuse or a Cap? - Page 1
Forum section: electronics / repair

author: sansan
author_rank: Contributor
timestamp: March 29, 2022, 09:03:58 am
content: Guys help me.What is that red box?it has T 3.15A (Ampere???) marking, but also have 392 (3.9nF???) on it.It is in series on the layout.. Mains layout.Is it a Fuse?It's a Laptop charger.Thanks.

author: wraper
author_rank: Unknown
timestamp: March 29, 2022, 09:08:56 am
content: It's a 3.15A fuse.https://www.littelfuse.com/media?resourcetype=datasheets&itemid=9d155b20-d018-47a8-841a-d1aa2fba25d6&filename=littelfuse-fuse-392-datasheet

author: sansan
author_rank: Contributor
timestamp: March 29, 2022, 09:17:28 am
content: Quote from: wraper on March 29, 2022, 09:08:56 amAh, 392 is the series name....what a confusing naming...thanks @wraper

author: Haenk
author_rank: Super Contributor
timestamp: March 29, 2022, 09:27:51 am
content: Not stated is the "T", which stands for "träge" (i.e. "slow blowing") in German. Just in case you are replacing the fuse with another manufacturer.Edit: That's why that series is called "time lag fuse", I guess

author: abdulbadii
author_rank: Frequent Contributor
timestamp: March 29, 2022, 10:11:47 am
content: can try google which gives all datasheet sites, so they'd tell us it's hi-V fuseor can try meter it which gives continuity to mean it's fuse that haven't blown upnote: to google get the mark having first character is letter or in so rare case a number followed by letteras whole number would refer only to registration, serial, or date/timestamp number
Is this a good place to post when hunting for Service Manuals?-Panasonic RX-FD55 - Page 1
Forum section: electronics / repair

author: phuzzyday
author_rank: Newbie
timestamp: June 05, 2025, 08:48:49 pm
content: I just got one from a yard sale. It's a portable Tape/CD/Radio machine. Surprisingly heavy!There are several issues to fix, probably nothing TOO serious, but I thought I'd see if I could find the Service Manual. Seems strangely rare!Thanks in advance guys!Phil

author: aeg
author_rank: Regular Contributor
timestamp: June 06, 2025, 12:00:21 am
content: These are not the same model but might be better than nothing:https://www.manualslib.com/download/3338900/Panasonic-Rx-Ds45.htmlhttps://archive.org/download/manual_RXDT55_SM_PANASONIC/RXDT55_SM_PANASONIC.pdfIn the off chance that your local public library still has a Sams Photofact online subscription, you can request a scan of the RX-FD55 manual.

author: FIXITNOW2003
author_rank: Regular Contributor
timestamp: June 06, 2025, 12:52:25 pm
content: got this if sim but 16 meg message me your email if you want copy ,,Panasonic RX-DT55 (GC_PX) ((sm-AD9105141C7).pdfalso panasonic-rx-fd-80-f-service-manual.pdf at 6 meg
Is this an 80ohm resistor? - Page 1
Forum section: electronics / repair

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 09, 2020, 09:12:51 am
content: As far as I can see this is grey, black, black,red a 4 band resistor which means it is 80ohm. Am I correct?

author: jaromir
author_rank: Unknown
timestamp: September 09, 2020, 09:20:08 am
content: Looks to me more like 10uH inductor; also see print on PCB (Lxx - usually inductors).

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 09, 2020, 09:24:45 am
content: Really? I saw the PCB and I also measure it about 1ohm, which indeed means it's an indicator.I didn't know that indicators have also this package..... Sorry

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2020, 09:27:34 am
content: The package is an odd width-length ratio too.Another clue that it's something non-generic.

author: drussell
author_rank: Super Contributor
timestamp: September 09, 2020, 11:37:26 am
content: Quote from: sdancer75 on September 09, 2020, 09:12:51 amNot only is it not a resistor, but you're reading the bands wrong, that is actuallybrown black black silver.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 09, 2020, 02:19:01 pm
content: Inductor it isand yes brown black black silver

author: sdancer75
author_rank: Frequent Contributor
timestamp: September 09, 2020, 04:33:08 pm
content: excellent thank you !!
Is this class X capacitor any good? - Page 1
Forum section: electronics / repair

author: StarkRG
author_rank: Newbie
timestamp: May 07, 2019, 12:17:17 pm
content: I'm getting ready to replace all the electrolytic capacitors in my Mac 512ke (entirely precautionary given it's about 33 years old) and discovered that its class X capacitor has some visual issues, its plastic dip skin is cracked and falling apart. I don't have a lot of knowledge about power supplies so I don't know what kind of capacitor this is (other than clearly being a class X, both because it has X on it and because it's across the live and neutral). I'm guessing it's not an electrolytic capacitor, and the skin is probably crumbling because it's old rather than because the capacitor expanded, but I'm not confident enough to just ignore it.Here are the pictures:https://imgur.com/a/ps2tGcjIf it does need to be replaced, can anyone give me an idea of what I should be looking for? (digikey doesn't have a "class x capacitor" section)

author: mzzj
author_rank: Super Contributor
timestamp: May 07, 2019, 12:45:59 pm
content: I would be willing to guess that its a WIMA brandwell known for cracking and/or catching on fireLast column "ratings" has option for X2 filterhttps://www.digikey.com/products/en/capacitors/film-capacitors/62?k=x2%20capacitor

author: Gyro
author_rank: Super Contributor
timestamp: May 07, 2019, 04:34:52 pm
content: That's the infamousRifametalized paper cap, smoke and flame will soon erupt!Replace with an equivalent value X cap without delay - even better, before powering it up again.

author: mzzj
author_rank: Super Contributor
timestamp: May 08, 2019, 12:42:05 pm
content: OK, what I was thinking?Rifa is the more "famous" also around here.(in my defense I have seen some wima brand paper caps also failing)

author: bd139
author_rank: Super Contributor
timestamp: May 08, 2019, 01:17:00 pm
content: Evict it quickly!To give you an idea how often these explode, I actually came across my 7th exploded one two weeks ago:Replace it with anything about the same capacitance, that is X2 rated and has the same pin pitch and same or better voltage rating.Honestly the RIFAs are pretty good. They had a design life though. I tend to put new RIFAs (now sold by Kemet) in where old ones failed and stick a sticker on the back with "replace RIFAs after DATE" where DATE is 10 years in the future.

author: Gyro
author_rank: Super Contributor
timestamp: May 08, 2019, 05:41:06 pm
content: QuoteYes, they do have higher dV/dt ratings than MKP ones. If it wasn't for the cracking and moisture ingress they'd be really good. Who knows, the epoxy composition might be more resilient these days.

author: bd139
author_rank: Super Contributor
timestamp: May 08, 2019, 05:45:31 pm
content: The new kemet ones are a different colour so possible. Fingers crossed! (and stuffed in ears)
Is this Grandstand FIREFOX F7 VFD game repairable or only good for spares?  - Page 1
Forum section: electronics / repair

author: Max Pleasures
author_rank: Newbie
timestamp: November 25, 2024, 07:23:38 pm
content: This Grandstand Firefox F7 was badly corroded to the logic board. I have extensively cleaned it and reflown every solder joint. Alas, the two columns right of the centre one do not display properly. They are very faint and as can be seen, some detail is missing. Is this a CHIP issue? Is it repairable or is it finished? I know that you can pass extensive current but I'm not sure this is a phosphor issue? Any advice before I scrap it would be hugely appreciated. Many thanks in advance

author: Max Pleasures
author_rank: Newbie
timestamp: November 28, 2024, 06:25:42 pm
content: Anyone any suggestions for this please?

author: coromonadalix
author_rank: Super Contributor
timestamp: November 28, 2024, 08:37:01 pm
content: pls do not pressurize people to answer, some may or will or if they want ... and you may not get answers ...

author: cruff
author_rank: Regular Contributor
timestamp: November 30, 2024, 05:38:10 pm
content: You can probably start with determining if you managed to clean all the corrosion that might be under chips and other larger components, which might involve removing them. Then look for traces or leads that have lost enough metal to become more resistive than they should be. Do you have a magnifier available to examine the board closely?

author: Gyro
author_rank: Super Contributor
timestamp: November 30, 2024, 06:45:53 pm
content: I doubt it is a phosphor issue (presumably each symbol will have be illuminated for roughly the same length of time) or filament emission (that would be more likely to follow the lines of the horizontal filaments). It looks more like the vertical grid drivers to me, try tracing back the grid connections and compare the signal levels with those of the working columns.

author: Max Pleasures
author_rank: Newbie
timestamp: December 05, 2024, 11:43:42 pm
content: Thank you for your advice.

author: Max Pleasures
author_rank: Newbie
timestamp: December 05, 2024, 11:44:50 pm
content: I wasn't pressurising anyone to respond. I was seeking a diplomatic and tactful means of bumping the post as it had disappeared from the page.

author: Max Pleasures
author_rank: Newbie
timestamp: December 05, 2024, 11:46:43 pm
content: Thank you, yes, I have a microscope There is a LOT of decay to some part of the board. I may well have to strip it down and try and study further. Thank you for the input.

author: Max Pleasures
author_rank: Newbie
timestamp: December 05, 2024, 11:48:38 pm
content: Quote from: Gyro on November 30, 2024, 06:45:53 pmAgain, thank you. I shall try this. It just appears to be those two columns to the right of the centre column. Most annoying!
Is this NiMH / Alkaline charger working fine? - Page 1
Forum section: electronics / repair

author: 7AudioBB
author_rank: Contributor
timestamp: February 17, 2025, 10:18:01 pm
content: I've got a LLOYTRON B1550 Alkaline / NIMH Intelligent charger that I've been using for years without any issues.Today I decided to measure the full charge cut off voltage so I connected my multimeter in parallel with the battery. That is when I saw something weird. The voltage keeps switching every second between the actual battery voltage and a voltage higher with 1 volt. For example the battery is at 1.4 volts, the next second I see 2.4 volts, then 1.4 again then 2.4 and so on. Is this behaviour normal with a HIMH charger? Is there a good reason to fluctuate the charging voltage? (By the way when there's no battery connected, the voltage is over 3 volts.)

author: ataradov
author_rank: Super Contributor
timestamp: February 18, 2025, 01:14:56 am
content: It is likely disconnecting the charge voltage from the battery to measure actual voltage. I would expect this to happen more frequently the closer it is to the target voltage.

author: RoGeorge
author_rank: Super Contributor
timestamp: February 18, 2025, 05:21:44 am
content: It is normal for a charge to do things like that, but if you measure 2.4V on a 1.2V NiMH, it means the battery has a very high internal resistance and thus not of much use. With a new battery, you should measure a max V closer to 1.5V than to 2.5V.
Is this triggering the short circuit protection? - Page 1
Forum section: electronics / repair

author: zodiacaca
author_rank: Newbie
timestamp: January 25, 2021, 10:44:00 pm
content: My PC suddenly shut down during moderate gaming, and can't boot up if the VGA cables are plugged in, after examining the graphics card I found no visual damage, only found these joints are suspicious, these joints are behind VRMs.I am a totally noob to electronic circuit, just curiosity.

author: ambrosia heart
author_rank: Regular Contributor
timestamp: January 26, 2021, 12:54:34 am
content: Gaming computer shutdown if Vga cableplugin. Cable not vga card???.1.remove display card.2.boot computer3.able to enter OS4.Display card problem.You can resolder bad pin to see if computer able to boot. If no boot still, display card problem. Something maybe shorted or BGA reballing needed most of the time.Besides motherboard Mosfets, coil & caps surrounding Cpu socket get very hot during gaming. If working in this condition for a long time, motherboard voltage supply to core and Cpu will break.Playing game makes GPU and CPU very hot. Good ventilation and tower cooler or water cooling are needed. Which game you are playing is also important. My game needs 4 cores to work fully.

author: zodiacaca
author_rank: Newbie
timestamp: January 26, 2021, 07:32:15 am
content: PC can boot with card plugged in, with cables it refuses.Didn't bother with the soldering, have already RMAed it.
Is this type of socket suitable for 2.5mm plugs? - Page 1
Forum section: electronics / repair

author: daisizhou
author_rank: Super Contributor
timestamp: July 17, 2024, 01:28:53 pm
content: Images 11and 22 show a 9V power charging socket.I don't know if the plug shown in picture 33 is compatible with it.Because the socket has a 3.5mm protrusion.If you encounter this type of socket, please help me confirm. Thank you