Repair a water damaged Macbook. Is it worth it? - Page 1
Forum section: electronics / repair

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: October 29, 2013, 02:28:38 pm
content: Hello!I got a water damaged macbook I want to repair. I opened it and found nothing obvious.Than I removed all the components and saw the backside of the logic board. It was quite dirty.I scraped some of the dirt with a little screwdriver off.Then I reconnected all the components and connected the power supply. There was no effect when I pushed the on button. The power supply works with with another mac, so I know it works. In addition, the screen is damaged. You can see a lot of tiny bubbles in the panel.Maybe it still works, but I can not test it as long as the logic board is not working.When I will have the macbook repaired, I either want to used it or sell it on ebay. I found a macbook that is working on ebay:http://www.ebay.de/itm/200980412901?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648The seller writes that sometimes the screen does not work or shows green rows. He sells the macbook for 200€ as an auction or 300€ if you want to buy it immediatly. Does it is more trouble than its worth to repair the macbook with the macbook from ebay? Or can I maybe repair the logicboard of my macbook? Is it very likely than components were dameged when the water went inside the macbook? Are there any fuses on the pcb that protect the components on the pcb? Can you give me instructions what I could check? I have a soldering iron, a scope and a multimeter.

author: ablacon64
author_rank: Frequent Contributor
timestamp: October 29, 2013, 02:44:14 pm
content: If you aren't experienced with laptop repair it could be a nightmare, macs are the most difficult laptops to fix, specially because of parts you don't usually find on stores or even ebay.The laptop should have been totally dehumidified before turned on, you may have permanently damaged it (well, maybe not "permanently" but at a point that's not financially viable anymore).

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: October 29, 2013, 03:01:56 pm
content: I have never repaired a notebook, only older machines like a scope and gameboys that had not such midget components. The notebook was in stand by mode when the water went in. It had not been turned on for half a year since it was damaged.

author: divelectservices
author_rank: Contributor
timestamp: October 29, 2013, 04:30:18 pm
content: Well at this point you have two options.You can replace the LCD screen and the logic board as assemblies. This will likely cost close to or more than you could buy a good used working one.You could learn how to do component-level repairs including reballing large BGAs, troubleshooting missing clock signals and voltage levels, etc. All without any type of service data or schematics. Parts will be difficult to near impossible to identify or obtain. You need to have plenty of spare parts and boards laying around!I do this almost every day.

author: ablacon64
author_rank: Frequent Contributor
timestamp: October 29, 2013, 05:05:52 pm
content: Quote from: Heribert Hechtersheim on October 29, 2013, 03:01:56 pmThat's not good also, half a year is a lot of time for corrosion to spread among the tiny components, including under BGAs. Wet laptops should be dried as fast as possible.Like divelectservices pointed, it's not a task you'll learn fast. I've been doing this for a living for about 12 years and still avoid water damaged units (just because time is money).

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: October 29, 2013, 05:11:34 pm
content: Quote from: divelectservices on October 29, 2013, 04:30:18 pmThank you for your answer!I would prefer repairing it on component-level because like you said, replacing the parts does not teach me anything and is not worth it. But that seems to be very challenging. I would like to start repairing it and stop it, if it gets to frustrating. Could you help me and tell me the first steps I have to check? I would really appreciate that.I forgot to mention that the lamp on the charger doens't light up when you plug it on the macbook.

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: October 29, 2013, 05:19:03 pm
content: Quote from: ablacon64 on October 29, 2013, 05:05:52 pmThank you for your reply!My brother put the laptop on the heating after it was damaged. What tools would I need to repair the Macbook? A heat gun? What can I check to get a better view of what is damaged and how much work and time I have to put into this project.

author: ablacon64
author_rank: Frequent Contributor
timestamp: October 29, 2013, 08:23:53 pm
content: Tough question. You can try analysing some laptops schematics (Google that) to try to understand how they work. Besides that, a strong knowledge on digital and analog electronics and patience (lots of it). You can also look for individual components datasheets to get to know what they do, how they are powered, what kind of signal(s) it needs to do its job, etc.

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: October 29, 2013, 09:36:39 pm
content: Your best bet is to ask on the macrumors forums.Ive recently fixed an A1278 with water damage,though nowhere near as bad as yours.http://forums.macrumors.com/showthread.php?t=972699Youll also find various schematics there .Good luck with it .EDIT: Clean up the board with isopropyl alcohol and a brush and see how bad it looks .The hardest part will be identifying all the parts that need replacing.Make a decision,try and repair it or salvage as many parts as possible to sell on,namely the HDD,memory,dvd , keyboard, and the logic board even in its present state would sell.

author: kripton2035
author_rank: Super Contributor
timestamp: October 29, 2013, 09:46:09 pm
content: you need isopropylic alcool (IPA), a toothbrush or an ultrasonic bath (or both)you spray the ipa on the corroded parts, then brush with energy and rince again with ipathen a bath some minutes with ipa under ultrasonic pulsesyou let it dry some hoursand you try to power onsometimes you have to start this over 2 or 3 times, depends if you have some "alive" signs or not.the display is dead you must buy another part but for the logic board it's not totally lost IMHOgood luck.

author: amyk
author_rank: Super Contributor
timestamp: October 30, 2013, 11:07:45 am
content: Macbooks are one of the easiest to find schematics on (next to Dells) because of their popularity... I don't know what exact model you have but e.g. try Googling "K36 MLB" which appears to be the '07 model. It's figuring out which parts are which on the non-silkscreened () PCB that is the main issue.If you don't already have familiarity with PC architecture and its troubleshooting (because Macs are PCs now) then this might be a good time to start learning... either way, give it a good clean first.After you get it cleaned, then start checking the power rails first. Laptops have around a dozen but just start at the main ones (B+, V+ -- battery/DCIN) and work your way down to the standby rails, then the runs.QuoteThat iscontrolledby theEC,which should be powered by one of the standby rails. You'll need to do more exploration from there, but the preliminary steps here are to make sure the standby subsystem (EC, charger, standby regulators) is all OK first.

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: October 31, 2013, 09:49:38 pm
content: Thank you all very much for your answers!Quote from: ablacon64 on October 29, 2013, 08:23:53 pmI googled and found the schematics for my model. It is an Apple MacBook Unibody A1342 (K87):http://schemalaptop.blogspot.de/2013/03/apple-macbook-a1342-mlb-k87-macbook.htmlI will attach the schematics here too.Quote from: fluxcapacitor on October 29, 2013, 09:36:39 pmI bought isopropyl alcohol on Amazon:http://www.amazon.de/gp/product/B001FSXLMU/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1I poured a bit IPA on the pcb and cleaned it with an electric toothbrush.The result does not satisfy me. Dust is still sticking on the pcb and components and the fluid left some lines on the surface behind. Maybe I have to repeat the process more times or pure more IPA on the pcb.For now, I will keep the parts. If I fail repairing the macbook, I will try to sell them.Quote from: kripton2035 on October 29, 2013, 09:46:09 pmI will try to repeat my cleaning. Sadly, I don't have an ultrasonic bath. How can I get the dust away which sticks on the PCB and the components?I found the first "alive" signs. When I connected the power supply, I noticed that the led of the magsafe connector glowed very very dim.I think that normally the connector should fade green and glow more brighter.Quote from: amyk on October 30, 2013, 11:07:45 amThat makes sense! I will try to start checking the powerrails. One problem I have is that I create very fast shorts with my multimeter probes. They are just too chunky. I switched to my scope which has smaller probe tips. The first thing I measured was the output of the power supply when its connected. The voltage drops down around every second/half a second (forgot my time/div setting).Thank you for the links, I will try to get the green light glow bright first.

author: DL8RI
author_rank: Regular Contributor
timestamp: October 31, 2013, 09:58:19 pm
content: Hi,if you want to go radical do it in the dishwasher (Glass-Program). That sould clean anything, after this into the oven at 50°C or if you have this "Nachtspeicheröfen" at home on one of these. Then total drying for days.Another Idea, less crazy, would be the TFT-Spray from Kontakt-Chemie. Optional: After cleaning pour with clean water and a brush, don't be shy but try not to dump coils, transformers, switches and so on.And, dry, dry, dry. At least 3 days on a warm spot.

author: TheBorg
author_rank: Frequent Contributor
timestamp: October 31, 2013, 11:09:43 pm
content: Quote from: DL8RI on October 31, 2013, 09:58:19 pmSeconded. I've done a couple macbook repairs, though none for very bad liquid damage. After you clean the board with any liquid you should let it dry a while.

author: Stonent
author_rank: Super Contributor
timestamp: October 31, 2013, 11:43:05 pm
content: A lot of that crud is dissolved minerals and electrolytes in tap water.You can use distilled water sold specifically for steam irons (and it should say on the jug) to rinse the water soluble minerals.Basically want to wash away the stuff the IPA would not clean. And once it looks as clean as possible then dry it the best you can, then pack it in a bag of dry rice to absorb the water.Anyway, that would be my next step if it were me and I was determined to try to get it working.

author: Bryan
author_rank: Frequent Contributor
timestamp: November 01, 2013, 09:10:16 am
content: Define "water", was it saltwater, then forget it the corrosion will only continue over time. I see a lot of corrosion which seems to suggest that either it was immersed in saltwater or water very, very high in minerals.

author: amyk
author_rank: Super Contributor
timestamp: November 01, 2013, 11:52:19 am
content: The "power system architecture" page of the schematic will be very useful for figuring out where to look for voltages.That F2117LP BGA is the EC. MC34845 below it is the backlight controller.Seeing as the LED on the power in connector is controlled by a digital protocol and it's turning on (under control of the EC), indicates there is some sign of activity and the EC might be running - you can scope the center pin on the connector to confirm the communication.

author: user23
author_rank: Newbie
timestamp: November 01, 2013, 12:53:34 pm
content: Hello to the Forum!!and about the macbook, i have just fixed a water damaged macbook. i did not got so mutch water as your machine but it did not work anymore. so the macbook was a total failure anyway. I decided to go for it and try to fix it the simple way, and hell yes it worked!!!!the macbook did have the problem that it wont charge anymore, the rest was fine. and it has same kind of corrosion inside...what i have done:take out the mainboard, clean it very good with some kind of PCB or electronic cleaner, brush all corrosion away, and then put it in to you'r ReflowOven... yes sure I dont have a ReflowOven as well... just put it in your oven, 230C for 15 minutes.let it cool down and reassemble the blody mainboard and see if it works...and yes, my macbook works again now, but since it was in the oven the wireles and Bluetooth dont work anymore... all the rest is now working again...gooooood luck!

author: HooRide
author_rank: Regular Contributor
timestamp: November 01, 2013, 03:30:04 pm
content: I have repaired at least 10 Apple laptops with water (water, margaritas(working on thesis, ha!), coke, etc.) damage.Some of the smaller spills that were handed to me within an hour of the incident were just a matter of cleaning the PCB with distilled water or PCB cleaner, a soft brush and then letting them dry.The badly damaged ones or the ones that sat for days before I could get to them are usually hopeless and even if they turn on after doing the above they may have intermittent problems.I would replace the logic board with one off eBay; and probably the LCD.

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 02, 2013, 03:35:36 pm
content: Quote from: DL8RI on October 31, 2013, 09:58:19 pmThank you for your suggestion. I decided to put my main board in the dishwasher too. Now I put it on the ground and let it dry because we have floor heating.Quote from: Stonent on October 31, 2013, 11:43:05 pmI didn't want to spend money again for distilled water and dry ice. The ipa was already an expensive purchase and I was very lazy. So I just put it in the dish washer.Quote from: Bryan on November 01, 2013, 09:10:16 amMy brother said it was a bottle filled with tap water which opened up in his bag.Quote from: amyk on November 01, 2013, 11:52:19 amThank you for your suggestions. I will check that when the board is dry again.Quote from: user23 on November 01, 2013, 12:53:34 pmThank you! What oven mode did you use? Circulating hot air or heating from above/below (I don't know the technical terms in english)? In circulating air mode, our oven can only get up to 190° C. Does gravity affect the components on the bottom side when the solder is liquid?Quote from: HooRide on November 01, 2013, 03:30:04 pmUnfortunatly, I have not found any good offers on ebay yet.

author: Unknown
author_rank: Unknown
timestamp: November 02, 2013, 04:26:57 pm
content: So to repair water damage, which might have created shorts because dissolved salts remain after drying, you rinse it with more water with the same salts and then dry it to make sure all dissolved salts get deposited on the board? Distilled water costs less than €1 per liter last time I checked.

author: user23
author_rank: Newbie
timestamp: November 02, 2013, 04:34:02 pm
content: Thank you for your suggestions. I will check that when the board is dry again.Quote from: user23 on November 01, 2013, 12:53:34 pmI put the PCB on a sheet of regualr paper, heat from above/below, and I dont know the best temp to use... and i think the oven temp is not that precise, so you have to test. and take all parts away from that PCB (i.e. heatsink, battery, stickers with serialnumber.., some parts get installed after the Reflow process and are not heat stable....

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 02, 2013, 05:18:43 pm
content: Quote from: alm on November 02, 2013, 04:26:57 pmI was too lazy to buy distilled water.Quote from: user23 on November 02, 2013, 04:34:02 pmDo I have to desolder the white plastic connectors(USB, LAN...)?

author: kripton2035
author_rank: Super Contributor
timestamp: November 02, 2013, 08:18:02 pm
content: Quote from: Heribert Hechtersheim on November 02, 2013, 05:18:43 pmyou wont be able to do it without very expensive professionnal equipment...I have a wmd3 weller worth $2000 and wasnt able to desoldier an audio jack from a macbookpro board... and it was a defective board so I didnt have to care about the surrounding components !

author: user23
author_rank: Newbie
timestamp: November 03, 2013, 10:48:59 am
content: no, all parts solderd on the board are heatresistant... they have gone through the reflowoven...

author: amyk
author_rank: Super Contributor
timestamp: November 03, 2013, 01:46:29 pm
content: Quote from: user23 on November 03, 2013, 10:48:59 amWith a specific temperature profile, however. They're not designed for anything more than the bare minimum necessary to survive one round of reflow.I would strongly not suggest going over 100°C, just to bake out the moisture.

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 08, 2013, 02:20:16 pm
content: Hey, I am back!I decided not to put the logic board again into the oven and startet to measure it. I did what amyk said and looked at the "power system architecture" page of the schematic. Then I found a broken 1 ohm resistor which was protecting the 3.425V "G3Hot" Supply. I shorted it with my multimeter and the current was only about 4 mA so I oversoldered it. I will replace it with a smd resistorbut I don't have them in stock.Then I was able to start the macbook. I heard the typical mac start sound, but the display was black. The color changes from dark green to black when it starts. I assumed that the backlight is broken. I searched on the pcb and found another broken fuse(F9800; 2A 32V) which was protects the LCD Backlight Driver (MC34845). Again, I shorted the fuse with my cheap multimeter on 10A range but this time I wasn't lucky. The current was higher than 2A so I quickly disconnected the multimeter. How much current should it normally draw? The voltage is 12.6V.Now I will check if any discrete components in the backlight driver circuitry are damaged or if the ic is the damaged part(How can I proove that?). It could also be possible that the LEDs or something else which is located on the screen is causing the problems.Thank you all for your previous help. I will appreciate further help, ideas and suggestions.

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: November 08, 2013, 02:35:25 pm
content: http://forums.macrumors.com/showthread.php?t=972699&page=10read post # 238The thread is over 60 pages but your model will be amongst them ,with part numbers ,pinouts,datasheets,pictures, and schematics etc .

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 08, 2013, 03:20:11 pm
content: Does it work with an external monitor?

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 08, 2013, 03:37:05 pm
content: Quote from: fluxcapacitor on November 08, 2013, 02:35:25 pmThank you! The picture that was posted showes exact the same fuse I found. I measured the current again between the fuse's ends. It was about 5A. But I saw no backlight.Quote from: NiHaoMike on November 08, 2013, 03:20:11 pmI don't know that at the moment, because I don't have the right adapter for my monitor. But I ordered one which I will receive tomorrow. Till now the only thing I can notice is the mac start sound and hard drive activity.

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 08, 2013, 08:12:44 pm
content: I found the problem. The 50V output from the lcd backlight driver was shorted. I tooke the lid apart and found a partially molten connector:The missing pad sticks in the connectorNow I will order a new screen and a new cable. It will cost me about 60€.I shorted the blown fuse and measured the output of the 50v lcd backlight driver. It is only 37V. Will it rise when a load is connected to it?The circuit is shown on page 67 on the service manual:http://schemalaptop.blogspot.de/2013/03/apple-macbook-a1342-mlb-k87-macbook.html

author: ivan747
author_rank: Super Contributor
timestamp: November 08, 2013, 08:16:00 pm
content: Quote from: Heribert Hechtersheim on November 02, 2013, 05:18:43 pmSo you were too lazy to spend 1€ on that for your €300 repair? I think you have just ruined the board.Scrap the project. Forget it. The best thing you can do right now is buy 2 broken MacBooks and mix all the working parts together and sell the rest.Maybe you can use the case of your water damaged MacBook and buy a functional MacBook with a broken case.Oh and the battery is probably dead as well.Sent from my iPhone usingTapatalk

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 08, 2013, 08:29:18 pm
content: Quote from: ivan747 on November 08, 2013, 08:16:00 pmI am making progress, why should I buy a new pcb?What do you think got damaged during the washing?I discharched the caps before I put it into the dish washer.Tomorrow I will receive my display port adapter so I can hook the macbook up to my external monitor. Then I will see if everything works properly except the internal lcd or not.

author: amyk
author_rank: Super Contributor
timestamp: November 09, 2013, 02:20:07 am
content: Quote from: Heribert Hechtersheim on November 08, 2013, 03:37:05 pmIt's alive...QuoteThat's normal, it means the LCD is receiving the right drive signals. You should be able to read the display if you shine a torch at it.QuoteWhich one exactly? It might've been a current sense resistor, and in that case you definitely need to replace it with one of the correct value.QuoteIt's a constant current, not constant voltage driver. Either way the IC can produce up to 60V but it's also PWM'd so I wouldn't expect maximum voltage unless the brightness is also set to max.(Checking for shorts is somethinga thermal imaging camerawould be very useful for.)

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 09, 2013, 09:16:32 am
content: Quote from: amyk on November 09, 2013, 02:20:07 amI marked the resistor with an arrow. The ~1k vaulue was the value the resistor had before I oversoldered it.The output voltage is a bit lower then the 3.425V but still higher than the minimum so I think that is ok.Quote from: amyk on November 09, 2013, 02:20:07 amAhh, that makes sense. In the datasheet(http://www.freescale.com/files/analog/doc/data_sheet/MC34845.pdf) they also say that "The 34845 includes fault protection modes for LED short and open, over temperature, over current and over voltage errors." So hopefully nothing got damaged when I shorted the fuse.Quote from: amyk on November 09, 2013, 02:20:07 amYou are right, that would make fault finding a lot easier. And they are usefull for other things too like finding cold spots in the house.I read this really interesting thread in the morning, but unfortunately I don't have the money to buy an e4.

author: cosmos
author_rank: Regular Contributor
timestamp: November 09, 2013, 09:54:14 am
content: The MF marking and circuit position of R6905 makes me think it most likely is a polyfuse.edit:I had a recent use of polyfuses in mind when writing that and their part numbers all started with MF-something ... when looking again at the schematic the other resistors also have the same MF-LF naming and they are for sure not polyfuses. So scrach the above on polyfuse.R6905 is a simple 1 ohm 1/8W resistor in 0805.

author: ivan747
author_rank: Super Contributor
timestamp: November 09, 2013, 12:05:19 pm
content: That's surprising! The motherboard is working!? We'll congratulations, Truly believed you messed up the motherboard. As someone else said, your backlight is probably broken. Try to get the computer in a very right room and move the display until you have no glare and try to see if the display itself is working, you should see everything. Also try increasing the brightness. Mac's minimum brightness setting turns the backlight off.Sent from my iPhone usingTapatalk

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 10, 2013, 02:40:49 pm
content: Quote from: cosmos on November 09, 2013, 09:54:14 amDoes MF stands for metal film? So the metall should get high-resistive when the current is too high?Quote from: ivan747 on November 09, 2013, 12:05:19 pmThank you! I did not believe it as well because I hooked it up to an external monitor and got no image, but then I put pressure on the gpu before I started the macbook and voila - I saw the desktop. I tightened the screws of the cooler and put the macbook back together. I don't know how permanent this fix will be. If it fails again I think I will put it into the oven.Quote from: ivan747 on November 09, 2013, 12:05:19 pmAs posted before, the leads for the LEDs at the LVDS connector on the pcb of the LCD panel were shorted and melted the plastic. I ordered a new cable and a new screen, because it has little bubbles inside due to the water.Everthing else(wLAN antenna, keyboard, touchpad, dvd drive) works fine.

author: TheBorg
author_rank: Frequent Contributor
timestamp: November 10, 2013, 10:33:51 pm
content: Really. There's not much here to say.First of all, when doing repairs like this please put in the time to do it right. Things like buying alcohol and distilled water? Not very hard to do, not all that costly (10 euros? maybe less). Washing the board with tap water introduces the same corrosives and minerals that destroyed the board in the first place. Not good.And alcohol, unless you buy a whole lot of it at an extremely high purity costs very little.It's a lot easier to help you get the whole thing working right if you slow down a bit and want to do it right.Secondly, one thing I learned on fixing these boards is to NEVER short out anything. Shorting out the fuse? Yeah, the problem was likely still there and you just blew the whole backlight circuit and the LVDS connector. Same with oversoldering components. They are there for a reason- its almost always better to wait a week and spend an extra 10 euros to get replacement parts than to try and repair the *entire* circuit later.That said, I'm surprised you got this far...Finally, I think the 50v you say the backlight needs is wrong, from what I have read this should be around 32v. Also, you should probably put some more thermal paste on the heatsinks and chips since you have washed the board so many times.

author: TheBorg
author_rank: Frequent Contributor
timestamp: November 10, 2013, 11:44:39 pm
content: Quote from: StevenWhitney on November 10, 2013, 10:56:40 pmYou said quite a bit.Ahh...Seemed less when I wrote it. Plus I was ranting a bit

author: amyk
author_rank: Super Contributor
timestamp: November 11, 2013, 09:06:53 am
content: "smoking out" bad components/shorts is an often-used technique for troubleshooting and it does work.

author: TheBorg
author_rank: Frequent Contributor
timestamp: November 11, 2013, 02:01:36 pm
content: Quote from: amyk on November 11, 2013, 09:06:53 amIn some instances, yes, this technique would work out quite well. However, I'd have to disagree for doing it here. Shorting out the fuse here with a potential short down the line could've very well had the OP replacing QFNs and green wiring traces. It's a great technique if you want to see if said component is causing the short, but can also cause bigger problems down the line. I've been a part of the macrumors backlight thread a while now, and I can say that shorting out high risk components (fuses especially) almost never works out well. I personally had to replace the backlight fuse in my macbook 3 times before I found the cause of the short.Then again, I'm not an EE...

author: Heribert Hechtersheim
author_rank: Contributor
timestamp: November 12, 2013, 02:04:43 pm
content: Quote from: TheBorg on November 10, 2013, 10:33:51 pmI think I would wash dirty boards again in the dish washer. Probably not if they have BGAs on them, because the dirt and moisture will maybe stick under the chips.If you dry the board after the washing, there is not much time for the metals to corrode.Quote from: TheBorg on November 10, 2013, 10:33:51 pmI cannot check every single component of the circuit when I work with such an overpopulated smd pcb. As a electronics beginner like me, I need very much time to figure out where components of the schematic are on the pcb.Before I shorted the fuse, I only checked how the components are connected. I must admit that I could have noticed that the LED cathode was shorted. It was a mistake that I didn't checked that.Now the connector is partially molten and I had to order a new one from Hong Kong which costs me 7€ and what is even worse: time (I have to wait maximal till christmas). I cannot say if the damage to the connector was done before by the water or after by me by shortening the fuse.Quote from: TheBorg on November 10, 2013, 10:33:51 pmYou are right, the 50V they wrote in the schematics would be too high. I disassembled the dirty screen and saw that the led stripe is splittet up into 6 lines which consist of 9 LEDs in series each. So if you say that every LED has a voltage drop of 3V you would need 27V per line to light the LEDs. If they cycle through the LED lines, the voltage of 37V I measured seems to be OK I guess. In addition, the voltage will probably drop if the LEDs are connected.