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Originally Posted by A1082  |
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I successfuly fixed my ACD what was dark and made 1short/1long/1short blinks.
I'll make pictures and post them here, but in short:
- replaced failed "1117-3.3SJ" LDO regulator [5V to 3.3V] located in a middle of main PCB.
This time I used slightly modified LM1086 what should handle max 1500 mA instead of 800 mA by original. |
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THANK YOU, A1082!!! Another satisfied "customer" for whom your fix worked like a charm.
Also, many thanks to
Freakin for the really detailed and accurate disassembly instructions (see message #11 in this thread). I probably would have broken something if not for his help.
I too have a 23" Apple Cinema Display A1082 which one day went black and made the LED power indicator blink in the pattern short-long-short. The Apple tech note on this exact symptom, which is at:
Apple LCD displays: Power light flashes
says: "Make sure you are using the correct power adapter with the display."
Now, since I never had any other power adapter, I knew that I
had to have the correct one (A1097 90W). I therefore figured that the power adapter is probably defective. I bought a new one from Apple support (of course, the 3-year AppleCare had expired about two months prior) and eagerly plugged it in - only to get the same symptoms (black screen, short-long-short blink on the LED).
Then I found this message thread.
Since I am reasonably handy with a soldering iron, I thought I would give it a try. The idea of A1082 to substitute a higher-amperage equivalent (LM1086) for the original part (LM1117) sounded like a good one - if these things are burning out for many of us, a heftier part might be more reliable. As was noted previously, the case size is a bit of a problem - the LM1086 comes in several case variations but they are all larger than the original, and the spot where it is soldered on the board is very cramped.
Rather than try to file down the case (and risk going too deep and hitting the important bits), I soldered extension wires to the LM1086 and "mounted" it off the upper edge of the circuit board using electrical tape. I used the TO-220 case variant, which is a LOT larger than the original.
It sure ain't pretty but it works perfectly. See attached photo. Actually, it's downright ugly. The replacement part is wrapped in several layers of electrical tape to prevent shorting to the surroundings. There is a black cloth tape with foil inside that shields the upper part of the board wiring - I peeled it back as shown in the photo and then pressed it down again to hold the new part in place.
By the way, if anyone else wants to try this - there are various electronic parts suppliers where you can get these things. I used Newark Electronics (which is actually located in Chicago) - they have it for $2.50 in single quantities.
NATIONAL SEMICONDUCTOR|LM1086IT-3.3/NOPB|IC, LDO VOLT REG, 3.3V, 1.5A, | Newark.com
I also attached a picture of the lower right corner of the opened-up case, showing the two mini connectors and the sliding latch that
Freakin refers to in his instructions. I thought it might help folks to visualize this before opening it up.
Also attached is the first page of a product data sheet for the LM1086 - you can get the whole thing at:
LM1086 - 1.5A Low Dropout Positive Regulators
Thanks again for a great resource. I only wish I had found this site earlier in my quest - I would have saved the $$ of buying a new power adapter that I don't need.