hybridfree/eevblog-posts huggingface dataset:
Challenge:  Open mirror with damage - Page 1
Forum section: electronics / repair

author: Bargainhunter
author_rank: Regular Contributor
timestamp: August 18, 2021, 06:27:41 pm
content: I am trying to repair my wife's makeup mirror. It is an iHome iCVBT7. The led lights do not operate. I traced the problem to the leds inside the mirror. It is here that I am stumped. I cannot find access to the inside of the mirror. There is a small seam around the edge of the mirror (see attached photo). I cannot get any type of tool in the seam to force the mirror apart. Has anyone ever succeeded in opening a piece of equipment that was press fitted? Your help would be greatly appreciated.Chuck

author: Leiothrix
author_rank: Regular Contributor
timestamp: August 18, 2021, 11:19:39 pm
content: I don't know about that specific device, but guitar picks are great for forcing snap fit seams apart.

author: sleemanj
author_rank: Super Contributor
timestamp: August 19, 2021, 12:20:14 am
content: Might be glued, I'd try heating it maybe.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 19, 2021, 12:36:22 am
content: It may be glued, have a snap fit or use double sided tape. If it's glued or taped, heating sometimes works. I would lay odds on a snap fit though. The bad news is that until it starts to come apart it's going to strongly resist.+1 on the guitar pick, that can be an amazingly useful tool.

author: amyk
author_rank: Super Contributor
timestamp: August 19, 2021, 02:47:43 am
content: Mirrors are usually glued from the back. Use heat and suction cups (don't pry, you're likely to crack it).

author: Bargainhunter
author_rank: Regular Contributor
timestamp: August 19, 2021, 08:00:26 pm
content: Thank you for all your suggestions.I tried the guitar pick but I could not get it in between the seam even with the thinnest pick.Suction cups is a very good suggestion. I will try that method with the heat.Thank you,Chuck
Chamberlain / Liftmaster Identity of power supply board chip? - Page 1
Forum section: electronics / repair

author: LaurenceW
author_rank: Frequent Contributor
timestamp: September 28, 2025, 10:29:01 am
content: Hi All, I am repairing a Chamberlain garage door SMPS board, looks like Chamberlain part number is 041A4023. It's from a ML1000EV, but it looks to be common to many garage door openers. Photo show a stock image of my type of board.The main SMPS chip is a Power Integrations LNK***G. I don't know what the***is, as that part of the chip detached itself when the chip blew its @rse to pieces! Rest of the circuitry appears OK. There appear to be several possible contenders from Digikey. Possibly LNK362, but I'm not sure.Can anyone with knowledge one of these boards enlighten me? Alternatively, I know I can buy a whole new board, but that's a long way from the cheapest solution, and shipping to the UK from Europe is hugely expensive, now (why thanks, Brexit!)

author: erkko
author_rank: Contributor
timestamp: September 28, 2025, 03:15:09 pm
content: I have managed to find such blown-off top -piece hanging around somewhere inside the case, handful of times even.

author: Andy Watson
author_rank: Super Contributor
timestamp: September 28, 2025, 03:37:26 pm
content: May be some hints in this thread:https://www.eevblog.com/forum/repair/help-identifying-blown-ic/

author: aeg
author_rank: Regular Contributor
timestamp: September 28, 2025, 11:00:50 pm
content: I found pictures of this board in eBay listings. Yours has an LNKxxxG, but it looks like Chamberlain also used Power Integrations SC1142D1 for that part.
Change voltage setting (factory set) for SFG-1013 (GW Instek) - Page 1
Forum section: electronics / repair

author: tmvieir
author_rank: Newbie
timestamp: October 14, 2019, 07:52:05 pm
content: HiI bought the function generator SFG-1013 a while back when I was living in the UK. Now I moved to the US and I would like to convert it to 100V/120V instead of 220V/240V.Has anybody done this before in this equipment? I attached a picture.Thanks

author: andy3055
author_rank: Super Contributor
timestamp: October 14, 2019, 10:17:06 pm
content: Looks like there is a provision to change the voltage right next to the transformer. You may have to pull out the part that looks like a resistor (may be some sort of a fuse) from the 240 volt connection and move it over to the 120 volt connection. You will of course have to follow up with the correct glass fuse F101 on the right side.Just to be certain, You could lift the board up and check the traces at the bottom and take some readings to compare the resistance of the windings. It will not be exactly half though.

author: tmvieir
author_rank: Newbie
timestamp: October 15, 2019, 09:52:23 pm
content: @andy3055 thank you! You are right. At the same time I posted here I also emailed the Instek folks, and they came back to me with this:QuoteI also attached the image they sent to me.

author: andy3055
author_rank: Super Contributor
timestamp: October 16, 2019, 12:22:54 am
content: Thanks. So, what they say is the standard fine print because they have to do that to cover themselves. The primary winding is as I expected and you don't need to lift the board unless you cannot lift the link from the top and move it to 120 Setting. However, they don't seem to mention the glass fuse on the right. You have to put in the correctly rated fuse there because it has to go up in value according to the print on the board. The lower rated fuse for 240 volts will blow on 120 volts.Like they say, you can attach a label on the power cord to confirm the it has been changed to 120 v.Good luckP.S. Make sure you pull the plug out before anything is done. It is easy to forget

author: tmvieir
author_rank: Newbie
timestamp: October 16, 2019, 09:48:54 pm
content: Thanks, andy3055. Yes, the manual says I should replace the fuse with a T0.315A 250V (the 240V is T0.16A 250V).Thank you for your help and insights on this.

author: andy3055
author_rank: Super Contributor
timestamp: October 17, 2019, 02:41:10 am
content: Glad you are able to get it sorted out.

author: tmvieir
author_rank: Newbie
timestamp: October 18, 2019, 04:04:49 am
content: Just to finish this thread with a success pic

author: andy3055
author_rank: Super Contributor
timestamp: October 18, 2019, 07:30:20 pm
content: Very professional looking! I like that green display. Great job. Thanks for sharing.
changing supply voltage from 115 volt to 230 volt on a Anritsu 4803a - Page 1
Forum section: electronics / repair

author: pe2ben
author_rank: Contributor
timestamp: November 06, 2023, 05:16:16 pm
content: Hello everyone,Before i buy Anritsu 4803a power meter on Ebay i want to know if it is possible to change the supply voltage from 115 volt to 230 volt on these meter.I hope it is only changing a tap on the transformer. I don't want to add an extra 115/230 volt transformer.Thanks Ben
Channel repair Agilent DSO 5000a - Page 1
Forum section: electronics / repair

author: Teichhermelin
author_rank: Regular Contributor
timestamp: July 31, 2020, 08:14:24 pm
content: Have any of you ever repaired a channel from an Agilent DSO5000? One of my channels is broken. nothing more is displayed on this. (Trigger goes to maximum negative value) Does anyone have an idea what it could be?

author: fpozzi
author_rank: Newbie
timestamp: November 05, 2024, 10:25:22 am
content: Dear All,I have the same fault on my Agilent DSO5012A, channel 1 is faulty, the signal is clipped at 500mV and the trigger has a negative value, is there anyone who can give me a suggestion or tell me where I can find the electrical diagram of the system board?Thank you
Charger Bosch GAL18V20 - Page 1
Forum section: electronics / repair

author: maher471
author_rank: Contributor
timestamp: January 05, 2022, 12:47:34 pm
content: Hello, I ask for your help to determine the type of transistor T5, T7 (SMD code MK3C) and help me understand the operating role of the set T5, T7 and R23, R33 in the schema.To simplify the repair I made the Reverse Engineering to make schematic, I join the diagram and other photos in the attachement;thanks in advance.

author: maher471
author_rank: Contributor
timestamp: January 05, 2022, 12:49:26 pm
content: Components Reference 1

author: lunacyworks
author_rank: Contributor
timestamp: January 06, 2022, 05:57:14 am
content: What software did you use for your diagram?

author: maher471
author_rank: Contributor
timestamp: January 06, 2022, 08:18:29 am
content: sPlan70

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 06, 2022, 10:40:55 pm
content: IMHO just PNP get controlled by IC2 as its base is IC2 output, to control / vary resistance || to load which in turn to control / vary load V which in turn to control load I (=VL/ RBatt internal R)It's cascaded to fine / enlarge the control (Q5 Q7)Please don't do incorrect label/symbolPlease correct label/symbol :Transistor : QTransformer : Tetc

author: maher471
author_rank: Contributor
timestamp: January 07, 2022, 11:42:50 am
content: Hi,1- Can you be clearer, more details, (It's cascaded to fine / enlarge the control (Q5 Q7))2- for the incorrect symbol it's not me, i use the Splan 7.0 to make the schematic

author: abdulbadii
author_rank: Frequent Contributor
timestamp: January 07, 2022, 02:58:06 pm
content: I meant this cascading is to fine/filter or get finer in control as PNP Q5 ouput, C, to Q7 input, Emust identify IC2 as soon as pos.there must be s.o. to find the setting for correcting the label

author: maher471
author_rank: Contributor
timestamp: January 07, 2022, 04:26:06 pm
content: i have try some combination : dual NPN : not work / dual PNP : work well / dual N-Mosfet : Not work / dual P-Mosfet : not tested (I do not have) but i think it will be work –what you suggest to me, uses two PNP or P-Mosfet (high-value resistor 4k7 driving)

author: inse
author_rank: Super Contributor
timestamp: January 07, 2022, 04:34:56 pm
content: Wow to both of you - Maher for his reverse engineering efforts and Bosch for design-to-cost efforts.There is not even any control of the charge current, the limitation is done by the primary current limit of the power supply.T5 and T7 could only be PNP or PMOS transistors, I havent come across SOT23's capable of switching 2A yet.The charger specs says it charges a 2Ah battery in ~1hr.I can imagine R33 is to provide a minimal current to measure the battery voltage without applying charge current.T7 will bypass the resistor for charging.T5 will turn on the charge current and possibly include a backup switch function for safety.

author: maher471
author_rank: Contributor
timestamp: January 08, 2022, 07:45:30 pm
content: thanks for the complimentfor information only the transistoe A19T is sot23 30v/4A
Charger IC for banggood lamp - Page 1
Forum section: electronics / repair

author: gaminn
author_rank: Frequent Contributor
timestamp: March 16, 2020, 11:37:35 am
content: I bought this lamphttps://www.banggood.com/XANES-24C-30W-COB-LED-Work-Light-Waterproof-Rechargeable-LED-Floodlight-for-Outdoor-Camping-Hiking-Fishing-Emergency-Car-Repairing-p-1537792.html?rmmds=myorder&ID=513344&cur_warehouse=CN(the red one) and instantly fried charger/step up IC.It is SOIC 8 IC, just 4c9d3z marking on the bottom side. Is it possible to buy this IC or whole PCB somewhere?
Charging cells in 2 laptop battery packs - Page 1
Forum section: electronics / repair

author: Shpeccy
author_rank: Contributor
timestamp: December 22, 2022, 09:29:23 pm
content: Hi. I was a bit curious as to why batteries in two different laptop batteries weren't charging so I'm looking for some opinions what to do with them and if they are salvageable.First up cells from a 34GKR E7440 packAs you can see two cells are swollen. Their voltage is 0 but I'm still not sure if they are safe to handle. I'd like to know how I can dispose of them.I can't seem to find replacement cells of the same type. I read somewhere the BMS is designed with a cell in mind so you can't mix cells though I'm not sure if I can just replace all cellsThe other two cells seem fine. They measure at 4.1V so they look like they are charged.The cells seem to be wired 2s2p so I'm also wondering can I wire the cells in series in order to use the pack at reduced capacity.Second pack is 722297-001 BL06XL from a dell laptopNo cell seems swollen although some measure a voltage below 2V. Most measure at around 1.5V while some measure 1.2V.My idea is to use side cutters to free them from the BMS then charge them with TP4056 boards and put them back on the BMS but I wanted to consult the forum on what to do before I start a lithum fire.Any and all suggestions are appreciated

author: TheMG
author_rank: Frequent Contributor
timestamp: December 22, 2022, 10:39:26 pm
content: The cells that are at zero volts can be disposed of the same way you would dispose/recycle any other li-ion battery. Negligible chance of these spontaneously combusting, as there isn't any energy left and in order to ignite there needs to be enough energy in the cell to create enough heat for the cell to vent and ignite the vented gasses.I would not attempt to recharge the cells that have dropped below 2V, over-discharge is damaging to li-ion cells and that does run some risk of fire I'm some cases if the cells are recharged from this excess discharge condition. If the battery pack's BMS won't allow the cells to be recharged after they have dropped to such a low voltage, there's a reason for this.
Chassis Feet for FLUKE 540B and FLUKE 343A - Page 1
Forum section: electronics / repair

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: November 17, 2021, 06:51:58 pm
content: most often, the chassis feet are missing from old FLUKE equipment. these are *.stl files for1. FLUKE 540B (set of 4), best to be printed in TPU95. 40% infill, brim recommended.2. FLUKE 5450A (1 piece), best printed in PLA or PETG, 40% infill. TPU95 isn't rigid enough. also fits 343A and other instruments in same chassis, and has side-rail for intrument-stacking. needs raft and brim to print properly. the three locator pins are slightly too long, simply snip to desired length.

author: tautech
author_rank: Super Contributor
timestamp: November 20, 2021, 08:44:40 am
content: We have a sticky thread for these such things.Suggest you also post here where it's easy for anyone to find.https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/
Chassis Rivet Removal. - Page 1
Forum section: electronics / repair

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 31, 2020, 03:26:10 pm
content: The component rivets inside the old tube chassis I am restoring were of soft brass and drilled out easily.Now I am trying to replace two RCA jack plates (**) on the vertical rear plate of the chassis.These are not accessible on the dimple side , inside of the chassis.The outer side rivet heads are chrome plated brass, domed, and a lot harder.There are six to remove. On two attempts the drill has started off centre , now the rivets are spinning.I though I would ask here of anybody with rivet removal experience, before purchasing a small cut-off saw.Thanks for any info.(**) The RCA jack plates do not work with present day RCA plugs with 1/8 inch. 3.2 mm pins.The jacks have a ceramic bushing with 4mm bore, and the spring contact is also oversized and does not contact.A banana plug (4mm) dia, engages properly.

author: CJay
author_rank: Super Contributor
timestamp: December 31, 2020, 03:41:56 pm
content: I've had good success with 'difficult' rivets and a pair of sacrificial wire cutters to cut the back off them but you say that's not accessible.I think perhaps a dremel and cut off disk to take the head off it might be a good idea but if you can't risk damaging the chassis or sockets then a needle file would also work

author: bob91343
author_rank: Super Contributor
timestamp: December 31, 2020, 07:56:28 pm
content: I've had the same problem many times. First try with a pair of cutters to grab the head and squeeze it out of shape. Maybe you can crush it enough to push it through the hole. Or cut off the head. Or distort it enough that it won't spin when you drill it. Or grind off the head. It would help if you could reach the back side and stop it from spinning. If you use a sharp drill and very little pressure it might not spin, at least long enough to remove some material.

author: mag_therm
author_rank: Frequent Contributor
timestamp: December 31, 2020, 09:23:53 pm
content: Thanks, Bob and CJ for the replies.I will try again. I see some little diamond wheels on Amazon.
Chauvin Arnoux C.A 6545 5kV Megger - Page 1
Forum section: electronics / repair

author: Mad Axeman
author_rank: Contributor
timestamp: December 22, 2023, 05:38:04 pm
content: We've got a Chauvin Arnoux CA 6545 5kV Megohmmeter that's developed a fault. Initial fault was it wouldn't IR at 5kV, zero volts even with probes open circuit. The 500v, 1kV and 2.5kV were fine. It was sent off for repair and we got told it was too old and parts were no longer available. Not being one to throw things away I took a look. Since it came back from repair(!) it had developed 2 more faults. It wouldn't charge (blown fuse on charge board) and all ranges now showed a 'Fuse G' fault. According to the manual this fault refers to the ground terminal fuse. After a bit of checking I found a cracked resistor which I replaced. It now works on 500v & 1kv but shows 'Fuse G' on 2.5kv and 5kv. There's a heat shrinked package (red package in last 2 pictures) connected between 'G' and '+' which contains 5 x 222 6Kv caps wired in parallel and 2 x 10k resistors (1 each side of the caps). I didn't have a capacitance meter with me to check these. Anyone have any experience of these meters and can shed some light on my next move or have a circuit diagram???

author: m k
author_rank: Super Contributor
timestamp: December 27, 2023, 06:35:56 pm
content: No experience nor schematics but arcing is clearly an option.Maybe it has some insulation problems.If so then possibly not very easy task.That line of 22ohm resistors, is the last one replaced?

author: Mad Axeman
author_rank: Contributor
timestamp: January 03, 2024, 09:23:36 pm
content: Yes, the last resistor was found to be broken when it came back from a quote for repair. Was fine when it went! I haven't had a chance to look at the unit since I posted my message but my next plan is to swap out the 5 x 222 caps (in the red heatshrink) between 'G' and '+'.

author: Mad Axeman
author_rank: Contributor
timestamp: January 05, 2024, 05:02:19 pm
content: I think I may have got to the bottom of the problem. I swapped out the 5 x capacitors and 2 x resistors and gave it a try. No more 'Fuse G' error message. 2.5kV range now works. 5kV tries but bombs out with a low battery error after trying to ramp up the voltage. Looks like my next job is to source a new battery and try again.

author: m k
author_rank: Super Contributor
timestamp: January 06, 2024, 01:32:41 pm
content: So a good guess is that the repair place tried to boost the battery with a charger and burned the fuse.How they broke the resistor is another thing, maybe all of those old mass resistors are more or less fragile.

author: Mad Axeman
author_rank: Contributor
timestamp: January 06, 2024, 02:57:54 pm
content: I was thinking of replacing all of those resistors. I had to buy them in a pack of 10 so I've got plenty there.
CHAUVIN ARNOUX CA 6411 Ground Tester - Repair - Page 1
Forum section: electronics / repair

author: 2X
author_rank: Frequent Contributor
timestamp: September 28, 2024, 07:01:06 pm
content: Hello,I have the “CHAUVIN ARNOUX CA 6411 Ground Tester” and when the jaws are closed it shows that are opened and also when jaws are closed, I am hearing a noise tic tic… like a relay open and closes periodically. Ι can’t open the jaws to see what is inside… does anyone open these jaws?Also, I made a schematic from the PCB that the connectors of the Jaws are connected but I didn’t find something and I replace all the chips with brand new except from these two (same) in the yellow circles where I can’t find a datasheet (Image 5). Any ideas for troubleshooting?

author: 2X
author_rank: Frequent Contributor
timestamp: September 28, 2024, 07:04:21 pm
content: At the attached files are all the datasheets that I found.

author: Catiablackcat
author_rank: Newbie
timestamp: December 04, 2024, 09:11:19 am
content: Hello, I am working right now with the same equipment but it is probably a lower version since I have more ICs in the pcb.I have noticed that if you do not have the clamps perfectly aligned and tightened during assembly you will get this error, but it does not work in all cases.In case you could solve the fault you could tell me how you did it.Best regards
Chauvin Arnoux E3N - Page 1
Forum section: electronics / repair

author: mendip_discovery
author_rank: Super Contributor
timestamp: February 01, 2024, 07:10:58 pm
content: So I have a Chauvin Arnoux E3N but it's got a broken coax at the end of the strain relief.Annoyingly I can see a screw that would allow me to get to the end of the cable where I might be able to repair the wire but I cant get to it becuase the handle is in the way.So anyone got any tips on how to take this thing apart?

author: Greybeard
author_rank: Frequent Contributor
timestamp: February 02, 2024, 04:02:25 pm
content: Pictures, please...

author: mendip_discovery
author_rank: Super Contributor
timestamp: February 02, 2024, 06:28:11 pm
content: So I had a go this evening at taking it apart. They really don't want you fixing these things.Managed to get the covers off the side, they lift up a little then rotate and ping off. On one side you can see a screw for a pot to adjust it.I manged to lever the case enough to get one side over the peg but the other side wouldn't go and I didn't want to break it. Might give it another go in a moment.

author: mendip_discovery
author_rank: Super Contributor
timestamp: February 02, 2024, 06:29:22 pm
content: Some pics fell off the last post.

author: mendip_discovery
author_rank: Super Contributor
timestamp: February 02, 2024, 06:46:22 pm
content: So I hit it with a hammer...

author: mendip_discovery
author_rank: Super Contributor
timestamp: February 02, 2024, 07:02:23 pm
content: and I am in,Turns out the core wire of the coax has broken.

author: Greybeard
author_rank: Frequent Contributor
timestamp: February 02, 2024, 07:04:14 pm
content: There are very similar Agilent, Fluke and Instek current clamps:

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 03, 2024, 12:43:55 pm
content: Going by the internal photos I believe Chauvin Arnoux are the OEM.Je ne dis pas ça par Chauvinisme

author: Greybeard
author_rank: Frequent Contributor
timestamp: February 03, 2024, 10:49:05 pm
content: Quote from: shakalnokturn on February 03, 2024, 12:43:55 pmYou're probably correct.I found this post here in the forum:Quote from: HighVoltage on August 10, 2016, 06:32:22 pmhttps://www.eevblog.com/forum/testgear/suggestions-for-dc-current-probes/msg1001757/#msg1001757The service manual including schematics of the AEMC Model SL261 can be found here:https://www.manualslib.com/manual/1561143/Aemc-Sl261.html?page=2#manualLast page of the service manual:Quote
Cheap 18650 work light mode controller?  - Page 1
Forum section: electronics / repair

author: Australia-learn
author_rank: Contributor
timestamp: March 29, 2025, 05:14:47 am
content: Hey guys. Brand new on the site. Lots of usefull info once I get some time to read.Anyway I'm just repairing for the fun of it. I'm doing all types of stuff🙂.Anyway got a cheap 18650 work light here that the main IC was getting red hot. 8 pin IC.It's running 2 PnP transistors and 1 P channel mosfet.Couple of resistors and stuff. Every component tests fine so I believe it to be the main IC that's died.Anyone got any clues as to what it may be? (See photos)I believe it has modes via a tactile switch.-also awear the charging IC is missing. I'm looking thrugh my scrap pile for a replacement 🙂.Go easy please. I'm awear it's probably a waste of time and bla bla. But I want to learn. And I get satisfaction from repairing stuff. Even if its only a $3 flash-light🙂.I got many other little projects here i need help with. Should I just add them here or start a new thread for each? Thanks

author: fant
author_rank: Contributor
timestamp: March 29, 2025, 08:35:06 am
content: No Photos.please attach pictures

author: Australia-learn
author_rank: Contributor
timestamp: March 29, 2025, 01:22:18 pm
content: Having trouble uploading pictures. See if this works 😐

author: tunk
author_rank: Super Contributor
timestamp: March 29, 2025, 04:40:46 pm
content: If you don't find that chip, you could try to bypass it and usea mechanical on/off-switch. You may have to experimentand/or replace the 1Ω resistor.

author: Australia-learn
author_rank: Contributor
timestamp: March 29, 2025, 09:57:29 pm
content: Oh yes I can easily bypass it however I would like to have the modes back. Had hi-low. And red. and there is a little led at the end, so 4 modes.Having a 4 position switch might be a bit cumbersome 😅

author: fzabkar
author_rank: Super Contributor
timestamp: March 29, 2025, 10:46:45 pm
content: Quote from: Australia-learn on March 29, 2025, 09:57:29 pmIt sounds like the IC may be a custom programmed microcontroller.

author: Australia-learn
author_rank: Contributor
timestamp: March 30, 2025, 07:06:28 am
content: Damn. I never really knew about these custom programmed chips. Always thought a chip was a mass production type thing. This repair world is gonna be a bit tricky if every IC is customised 😬.Come on China. Go back to basics 😅
Cheap and cheaper, mini Solar LED light repair - Page 1
Forum section: electronics / repair

author: electr_peter
author_rank: Unknown
timestamp: October 15, 2022, 11:48:15 am
content: Solar chargeable LED light for keychain stopped working, while similar one still works. Construction is identical in both with the same case*, PCB* and solar cell. 1st unit charges in the sun, while 2nd unit is dead because it usesnon-rechargeable battery, has no diode installed and solar cell is not connected.Repair is easy, though.These LED lights seem to be marketplace special - functionality depends on the cheapest components available that week. Did rechargeable batteries run out? Place non-chargeable ones instead and remove (i.e. save few cents) diode and few connecting wires while you're at it. LED light still kinda works on coin cell. There is no obvious way to test if solar cell is connected.Overall, these cheap mini LED lights are acceptable if solar cell works and you can get them for low price. Otherwise get something better.* - cases and PCBs have minor differences

author: electr_peter
author_rank: Unknown
timestamp: October 17, 2022, 07:05:39 pm
content: Earlier hand crank LED flashlight that stopped working was repaired. Internal 3.6V 40mAh NiMH battery was flat becausedynamo circuit was wired wrong(in short circuit)and thus did not charge battery.I strongly do not recommend this type of flashlight - bad quality and usability.

author: electr_peter
author_rank: Unknown
timestamp: October 28, 2022, 05:07:38 pm
content: TechBenchvideo shows identical fake solar flashlight from inside (i.e. non-rechargeable battery, unconnected solar cell).What's inside a fake solar flashlight (#013)
cheap asian supplier for EL electroluminescent backlight (or LED replacement)? - Page 1
Forum section: electronics / repair

author: Greybeard
author_rank: Frequent Contributor
timestamp: August 24, 2021, 05:44:02 pm
content: I need an EL backlight panel ~80x125mm for an Optrex DMF 682A liquid crystal dot display.I searched ebay for chinese suppliers, but they were 12-20$ +19%VAT (not much cheaper than local suppliers in Germany).Is there something like a LED replacement for such EL foil type panel? Panel thickness is max. 2mm.Can I cut EL foil to needed dimensions?Do I need to seal cut edges? Zinc sulfide is said to be hydroscopic.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 24, 2021, 06:02:31 pm
content: Quote from: Greybeard on August 24, 2021, 05:44:02 pmYesQuoteYes, but not sure how practical it is to get a good enough seal - laminating pouch perhaps?

author: james_s
author_rank: Super Contributor
timestamp: August 24, 2021, 06:46:25 pm
content: About 10 years ago I replaced the EL strip backlighting the display in my Pro-2004 scanner radio. I bought a strip from China, cut it to size with scissors and folded a strip of clear packing tape around the whole display in an attempt to seal it. I actually doubt the tape accomplishes much, it's not going to keep humidity out. So far so good though, it doesn't get a great deal of use but it still looks as good as the day I installed it.

author: Greybeard
author_rank: Frequent Contributor
timestamp: August 25, 2021, 12:59:05 pm
content: It's nice to hear of a working "tape sealed" EL strip after ten years!Laminating pouchesYes, I thought about laminating, because the defective original EL foil looks like a laminating pouch.I'm not quite sure, how laminating pouches work exactly. Is it 2 layers of one material, that is molten by heat and pressed together, or is it 2 outer layers of non-melting material and one or two additional inner layer(s) that are molten and then pressed together?What about using clear nail polish or cellulose lacquer to seal the cut edges?

author: james_s
author_rank: Super Contributor
timestamp: August 25, 2021, 04:52:47 pm
content: Laminating pouches are a sheet of material that has been folded in half with the inner sides coated in a heat activated adhesive. You open it up, insert the item you want to laminate, fold it back closed and then run it through the machine which has heated rollers that fuses everything together.I'm not sure I'd want to try coating the edges with something liquid, that may flow up inside the EL strip by capillary action.

author: Greybeard
author_rank: Frequent Contributor
timestamp: August 25, 2021, 05:59:15 pm
content: Then laminating the cut sheet probably is the way to go.I hope the hot rollers will not degrade the performance of the "phosphor" (=zinc sulfide).

author: james_s
author_rank: Super Contributor
timestamp: August 25, 2021, 07:34:02 pm
content: Well it only takes a few seconds to go through the machine. I suppose you could pick up a small cheap strip and run it through the laminator at various speeds and temperatures and see when/if it fails or noticeably degrades.
Chinese 24V SMPS Failure s-360-24/NxP365SP-V03 - Output Coil Failure - Page 1
Forum section: electronics / repair

author: xfd1001
author_rank: Newbie
timestamp: March 02, 2022, 06:47:00 pm
content: Hello,I have one of those cheap 24V switch mode power supplies in use for the LED lighting, it has been running 2 years but now it has come near to it's end.The big output coil started overheating, the output is fluctuating between 23-28V, caps look all good.Can anyone point me in the right direction?It's a bit hard to see in the pictures due to the light; under the coil the PCB has discolored because of the extreme heat.Update:Found this schematic online of a similar power supply and it doesn't make any sense to me how the coil can overheat that much...

author: tunk
author_rank: Super Contributor
timestamp: March 02, 2022, 07:40:00 pm
content: Even if the "caps look all good", they can be bad:https://www.eevblog.com/forum/repair/help-with-power-board-of-old-bernina-sewing-machine/

author: xfd1001
author_rank: Newbie
timestamp: March 02, 2022, 07:57:39 pm
content: Thanks for your reply and the post; I just checked the 3 output caps with my ESR meter and all 3 caps come out as goodJust don't understand how it can be the ferrite; there must have been some significant current running for it to heat up this much

author: TheMG
author_rank: Frequent Contributor
timestamp: March 03, 2022, 12:56:44 am
content: Don't overlook the smaller electrolytics on the primary side, they can be a common cause of malfunctioning SMPS.The output inductor overheating could be related to the failure, or could just be bad design and it always runs toasty.

author: tunk
author_rank: Super Contributor
timestamp: March 03, 2022, 12:13:15 pm
content: Wouldn't really know, but if you have some contact cleaner,maybe you could try it on the adjustment potentiometer?
Cheap chinise buck converter power supply odd failure - Page 1
Forum section: electronics / repair

author: justin66
author_rank: Regular Contributor
timestamp: October 01, 2020, 08:20:12 pm
content: Hello guys, i have bought cheap buck converter cc cv module. It failed on me after a couple.of short circuit tests. It came out to be choke short. I fixed it. For temporary use i fited irf50n06 transistors, the power supply was fine and managed to withstand many short circuit tests. So i decided to put very good, low rdson transistors irfb3077. The first short circuit test and the main buck converter chip blown xl7005, should i try fixing it again? Or is this module is just crappy design? It says it has over current protection.€ 15,33 5%OFF | WZ5020L WZ5012L DC DC Buck Converter CC CV Step-down Power Module 50V 20A 1000W Adjustable Voltage Regulated power supplyhttps://a.aliexpress.com/_mOyQgkX

author: thm_w
author_rank: Super Contributor
timestamp: October 01, 2020, 10:17:23 pm
content: Did you remove that capacitor on the left side?They say it has overcurrent protection but they don't specifically mention output short circuit protection. Its possible if its using software control to limit the current, a short could still cause damage, vs a slight overcurrent condition.
Cheap clock repair, why?? - Page 1
Forum section: electronics / repair

author: joeqsmith
author_rank: Super Contributor
timestamp: July 25, 2021, 07:45:10 pm
content: My wife was given a clock many years ago. One of the trinkets from a previous job so had some sentimental value. It stopped working today and noticed a bit of acid but no apparent damage. Cleaned it up and replaced the battery but it wouldn't run. Cheap plastic works that snaps together. popped it apart and bits flew all over the desk.Acid had damaged a but of the PCB where the battery contact mates to it so I just tinned that. The real problem was it had damaged the coil winding. I thought I would remove a half turn, but that was a bust. The wire is about the thickness of my whiskers. Razor blade was used to scrape off some of the insulation, cleaned and tinned then added about an inch of new wire. A bit of clear nail polish to secure it.Then the task of figuring out where all those bits fit.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 25, 2021, 07:47:56 pm
content: Finishing up. This was a bit of an odd ball works and I wasn't able to find pictures of one. Maybe these pictures will save someone the pain of repairing one of these cheap clocks.

author: floobydust
author_rank: Super Contributor
timestamp: July 25, 2021, 07:51:37 pm
content: I also got a clock to repair, the 'sentimental value' kind of thing. I did research and found there are only a few standard clock mech's used. Mainly the mounting for the hands, shaft length.Because the gears simply wear out, I ordered a few from Ali and it was much less hassle at maybe $3.Newer clock mechs do not have a 1PPS tick tick tick solenoid but instead some kind of silent smooth movement, like a motor running, still 1.5Vedit: It's got a chime? That would make it harder to source.

author: Runco990
author_rank: Frequent Contributor
timestamp: July 25, 2021, 09:13:17 pm
content: Normally I don't repair a $2 quartz movement, but I have one clock where they screwed up and produced an extremely accurate one..... so when the battery (Duracell of course) exploded WHILE STILL RUNNING.... I had to save it. This crap movement is accurate to a minute or two a year. TOTAL screw-up! I'm milking it for all it's got!

author: joeqsmith
author_rank: Super Contributor
timestamp: July 25, 2021, 09:23:57 pm
content: It has a beeper for an alarm. The ones I am used to seeing have a single nut that holds them to the clocks face. This one has has three screws that secure it to to the face. It may have been custom as I wasn't able to find a match.
Checking equivalent parts for an arcade monitor chassis - Page 1
Forum section: electronics / repair

author: MrKnockoff
author_rank: Newbie
timestamp: December 29, 2022, 10:09:21 am
content: Hi Everyone,I'm repairing an arcade monitor chassis and I've had to use a few equivalent parts. I wanted to check that I have picked the correct ones that are compatible.I needed a replacement for a fs14sm-16a (N-Channel MOSFET Transistor) and this seems to be a IXFH14N80P.Vds match, 800V, Vgs match +/- 30v, Id match 14A and also Rds(on) match 0.7 ohmAnything else I need to consider here?I also needed a replacement for 2sc5144 (Horizontal deflection output) which seems to be a FJL6920TU.Vcbo match (1700v), Vceo higher (600 vs 800) and Vebo higher (5v vs 6v). Ic is the same, 20A DC, but pulsed is 30A vs 40A. Pc is the same, 200W.Will this function the same, or do I need to consider the rest of the circuit?I also needed a replacement for a KA3842B (SMPS Controller) which seems to be UC3842B (High Performance Current mode PWM Controller).The supply voltage matching (30v), output current match (1A), analog inputs are slightly lower, -0.3 to 6.3v vs -0.3 to 5.5v, but power dissipation matches at 1.2 W (well 1.2w vs 1.25w close enough).Have I done the correct parameter matching here? I wanted to double check with someone before I go blowing up the chassis.

author: fzabkar
author_rank: Super Contributor
timestamp: December 29, 2022, 05:29:51 pm
content: ISTM that your substitutions are OK. Some line output transistors have base resistors or a diode between C and E, but yours are straightforward. That said, I always hate subbing these transistors because I am never sure how they will function. I suggest you run the monitor for a minute, switch it off and then feel the temperature of the transistor. If it runs cool, then soak test it for a few hours.I would also suggest that you test and replace any high ESR capacitor in the drive section, and reflow the solder to the pins of the drive transformer even if they look OK.Edit:I recommend that you avoid Chinese sources. Too many fakes ...

author: MrKnockoff
author_rank: Newbie
timestamp: December 29, 2022, 10:09:34 pm
content: Thanks fzabkar. I've already done a full replacement of the capacitors and all parts are from the major parts suppliers, mouser, digikey, wes components etc. It looks like it failed and someone tried to get it going by doing insane things like shorting the in rush current limiting NTC etc. That resulted in blowing several IC's like the PWM controller etc. Lots of soot around the flyback which I have already sourced too. Hopefully I'll get it back running.
Cheesy charger circuit - Page 1
Forum section: electronics / repair

author: PaulAm
author_rank: Frequent Contributor
timestamp: January 23, 2023, 10:05:20 pm
content: I had to repair the charging circuit on an old Wavetek CATV meter. When I pulled out the manual and looked up the circuit, I couldn't believe they cheaped it out that badly. This was for a 15V Nicad battery pack.I resisted the urge to improve things and just found a couple of replacement lamps in my spares,
Cherchez la capacitor - Page 1
Forum section: electronics / repair

author: 5U4GB
author_rank: Super Contributor
timestamp: December 24, 2024, 12:42:10 pm
content: Thought for the day: In detective fiction, a standard cliche to find the motive for a murder is "cherchez la femme". In electronics when something dies it's cherchez la capacitor.(le condensateur if you want to get pedantic).

author: bairdbankovic
author_rank: Newbie
timestamp: December 25, 2024, 11:45:35 pm
content: Like the analogy -- I'll have to use that

author: Analog Kid
author_rank: Super Contributor
timestamp: December 26, 2024, 12:20:45 am
content: Then there's Walt Kelly'sChurchy La Femme:

author: timeandfrequency
author_rank: Frequent Contributor
timestamp: December 26, 2024, 09:38:53 am
content: Quote from: 5U4GB on December 24, 2024, 12:42:10 pmOr actually if you want to write it correctly in French
Chevy Volt Shift to Park Repair - Page 1
Forum section: electronics / repair

author: carlover72
author_rank: Newbie
timestamp: December 03, 2021, 07:50:08 pm
content: Hi all,To anyone with a Chevy Volt experiencing shift to park issues... I recently read this articlehttps://lemonlawexperts.com/a-shift-in-focus-for-chevrolet-shift-to-park-defect/which mentions that the tsb Chevy has released says to add an in-line shifter wire harness jumper between the console harness connector and the shifter base connector. Saw some posts on here about the problem, but never saw this solution in the forum- not sure if it will actually fix the issue, but wanted to include it for anyone having these problems in case you wanted to try it out. Seemed to work for me.
chieftec cft-850-14c sudden shutdown with or without load - Page 1
Forum section: electronics / repair

author: montarbo
author_rank: Contributor
timestamp: May 29, 2019, 11:02:13 pm
content: Dear members,PSU which was used in PC since 2010 without problems. Recently I started getting random sudden shutdown. I narrowed it to the PSU. Unit tested in Another PC with same behavior, the PC itself runs without problem with Another PSU.The unit itself has CM6800G on the hot side on a daughter board. Protections done by PS229 and WT7518D on the cold side on another daughter board which also has fan control.The psu works fine for 10-15 min at load but shuts down either under load or as soon as it goes to idle, sometimes even without any load just shut down at idle. All caps on main board measured within specs (on and off board measured with ESR). I changed the caps on the protection board but they where all good just to bee sure. Still the same with shutdowns. Added a resistor in parallel to resistor in series with PGI of PS299 and raised the voltage from 1.16v to 1.32 volts. Changed PS229, Still the same behavior.Monitored the 5v stb,+3.3v, +5v and 12v with multimeters during 4 cycles of random shutdowns, two at load and 2 at idle. Nothing strange with those voltages just zeroing suddenly at shutdown though solid 5v stb at 5.18 all the time.The +5v at 5.19 - 5.20 at load - idle.+12v at 12.17 - 12.11 att load - idle.3.3v at 3.35-3.42 att idle - load.Any ideas where to look? anyone came across same problem?BR
China Xeltek Superpro 5K 6K CX DX Adapters Unmatched Adapter Error Fix. - Page 1
Forum section: electronics / repair

author: KG7AMV
author_rank: Frequent Contributor
timestamp: December 05, 2021, 06:19:52 am
content: I Did a little video and a blog post on theBlog Posthttps://www.stevenrhine.com/?p=60579I Hope it helps some people.
Chinese 852d+ rework station - Page 1
Forum section: electronics / repair

author: Tamasteve
author_rank: Newbie
timestamp: April 20, 2022, 07:16:28 am
content: Hi my hot air gun overheats(red hot) i checked triac and 1 piece was shorted but its for air pump. After some reading up i changed lm358 and moc3041 (as i read shorted phototriac causes full power) but its still over heats. I even bought new hot air gun bcos the old one's internal glass holder broke. But it still over heats. Its a 852d+ where do i go from here.Can u advice?
Chinese generator - Page 1
Forum section: electronics / repair

author: fant
author_rank: Contributor
timestamp: July 21, 2019, 03:10:10 pm
content: Good morning;I have bought with aliexpress a signal generator as the picture in the attachment.Powered, no sign of life.Contacted the dealer, no answer, and aliexpress refused to press the dealer to help me.From what I have seen and checked, seems to me that the firmware si corrupted or absent.So, anybody that bought the same generator, can make the dump of the FW?Here is the page of the generator:https://aliexpress.com/item/32949111006.htmlThank you in advance

author: testpoint1
author_rank: Frequent Contributor
timestamp: July 25, 2019, 03:59:28 am
content: return it, that is easy

author: FrankBuss
author_rank: Unknown
timestamp: July 25, 2019, 07:29:16 am
content: Usually Aliexpress has a good customer protection. But I bought once something from Alibaba, which is more informal, and the parts where broken, seller didn't respond. Had to refund it via my credit card company, but this worked.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 25, 2019, 10:27:18 am
content: Yean make your point and tell them it doesnt work, you want a refundAliexpress should protect you, it did for me, (very very long shipping, missing items, and one who did not work)Are the boards slightly disconnected, theres two stacked togetherand the lcd touch panel and drive signal, is it well connected too ??
Chinese plasma cutter/tig welder only getting a spark! - Page 1
Forum section: electronics / repair

author: Raylicker
author_rank: Newbie
timestamp: July 05, 2020, 11:22:29 am
content: Hi all, I have an Accurate Tools plasma cutter/tig welder that was working fine. I went to use it the other day and now only getting a slight spark from the gun, also getting a little shock from case.. Getting arc on those two poles inside and don't see any burnt or anything abnormal inside. Attached are some pics of it. Please anyone some help. Thanks for reading this.https://www.eevblog.com/forum/Smileys/default/scared.gif

author: EPTech
author_rank: Regular Contributor
timestamp: July 05, 2020, 02:21:20 pm
content: Hi there,Sounds like the HF pilot arc is working but you do not get the main arc. Many things can cause this. Blown rectifier diodes are the most common.Try measuring the voltage on the secondary side, while pressing the trigger. Do not measure at the torch or anywhere between the torch and the choke as this will possibly ruine your meter.You should measure around 70V open circuit. Depends from welder to welder. It wil drop conciderably once you establish an arc.Be carefull. You are measuring on a high engergy circuit. I advise using clamps to probe what you want to probe, then power on the unit, operate it, and then measure.Good luck.

author: trevatxtal
author_rank: Contributor
timestamp: July 05, 2020, 03:13:54 pm
content: Check the relays, common fail point.Watch them when you press the trigger.