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Everything is working perfectly fine but I just can't see anything. Apple said it had water damage and to buy a new one. I just can't see buying a new one if it works fine with the exception of viewing it. Can I just replace a light?
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Be careful. We just replaced the screen on our Ipod Gen 4 to try to address the backlight problem, and the new screen had the same problem. It seems like this is a problem with the Gen 4's, but it is unrelated to the screen. We have tried adjusting the brightness and turning off the energy saver, etc. Nothing works.
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I agree with Melissa and Oldturkey, I have a few logic boards that do the same thing. I'm wondering if the powering circut for the backlight goes bad easily. Most of the ones that have this issue have some signs of water damage, so I assume the power circut goes bad on the logicboard or there is a bad connection to the LCD screen.
crwdns2894046:0crwdne2894046:0
Cmd, I was just wondering about something. You know about the iPod touch having issues with the 6R8 backlight coil shortening out and rendering it useless. Now I know I have a fix for that somewhere in my "Magic Notebook" Do you have a Nano logic board handy to check if that one has a coil similar to the 6R8. May be the same fix could be applied to that......
I have a good 4 or so boards with the same issue as the orignal poster and a few with click wheel issues (with good click wheels). To answer your question, I do have extra boards around for ipod nanos, but I have not worked on any iPod touchs. I would be interested in that fix for the touches to attempt on the nanos I have. I do know they have multiable coils on the main board. If I remember correctly, 2 are located on the back side near where the battery is soldered on and one on the oppsite side. All appear to be the same size but haven't had time to look into it further.
the fix is also applied for the iPhone 3Gs...:) here is a link to it. http://blog.techsick.com/guides-tutorial...
Nice find, too bad they don't say where they are pulling the power from, if it is long lasting, and the voltage.
Also since LEDs are used for the backlight, I would assume they don't go out very easy. I read about 8.5V DC on the unit I have here, and was able to test the backlight with 7.5v DC to 9v DC with no issues. See photo for test locations on LCD.
http://img810.imageshack.us/img810/208/n...
Next would be to find the direct connect on the board, and provide power there to see if the ribbon cable is getting connection. If all of that tested good, then I would say 95%+ chance the coil is bad.
Warning: the above test is easy to slip up and short something out, make sure the LCD is NOT connected to the main board while testing, I do not know if any damage would result. Also provide power for as short of time as possible since the current is not controlled and could reduce the life of the LEDs very quickly.
You can also test the coil with a multimeter. Of my readings on two ipods i have here, they should read 0.4 to 0.6 ohms. If it reads very high or no connection it is bad. I learned this trick when I worked on PS2 lasers and their coils, and related system issues.
Now that I think about it, the old PS2 V9/10 and V12 fix for the laser coil issues might be a good idea for these iPods. I don't know enough about them, but basically the fix was to cut the trace that gave the laser coils up to about 9v and dropped it down to around 7.5v via resisters.
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I do wholeheartedly agree with Melissa, Just had the same experience on 3 different Nano's. All three had the same problems and on further examination upon disassembling the Nano's I found corroded cables on the LCD ribbon. What is noteworthy here is that none of them had any known previous water damage. The ribbon is attached to one of the inner layers of the main circuit board. It's not possible to replace just the cable.I did replace the screens and cleaned the corrosion as good as I could and got one working but had to replace the other main boards. I would still go ahead and try it :) The cost for the display really wasn't that bad and it might just be a good challenge. Good Luck...
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Hello Friends,
change the coil below the display-ribbon.
It works fine. I´ve got this problem a serval times.
Greetings !
Joy
crwdns2894046:0crwdne2894046:0
Joy,
can you send me a picture and the details of the coil please?
Please ask Questions as comments only Answers belong here.
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