Will not turn on after attempting to change backlight fuse

[cosmicvoyager]

Greetings,

My screen was black. I could see with a flashlight that the computer was on. I determined the back light fuse was blown.

When I tried to desolder it, I shorted to nearby component. The motherboard was not unplugged from battery.

Now, absolutely nothing happens when I press the power button. Can anyone please point me to where the problem is likely to be now?

Thanks

[goontron]

Re: Will not turn on after attempting to change backlight fuse

Well, that small chip next to it looks like it may be cratered. Or that may be some flux stuck on it.. Im not intimate with iDevices, so iCouldn't tell you what that is....

[ktmmotocross]

Re: Will not turn on after attempting to change backlight fuse

it may be driver fot the main power woltage because power connector is near on the other side of board.

give us full board marking to check what is that component.

ah sorry i see the marking on board now

[ktmmotocross]

Re: Will not turn on after attempting to change backlight fuse

looks like it is LCD backlightdriver. if u burnt it because u have high voltage on fuse, it can shorting VCC line.

[cosmicvoyager]

Re: Will not turn on after attempting to change backlight fuse

looks like it is LCD backlightdriver. if u burnt it because u have high voltage on fuse, it can shorting VCC line.

Thanks for reply. Yes, it is the backlight fuse. I think I shorted F9700 to R9755. So PPBUS_G3H to ground. I am using schematics for the first time. I am wondering what the most likely damaged part is. I guess I need a mulitmeter.

http://www.apple-schematic.se/board/...o-13-mid-2012/

[ktmmotocross]

Re: Will not turn on after attempting to change backlight fuse

u will neeed much more than multimeter to solve this problem. i think u cannot repair it.

[raajkumar]

Re: Will not turn on after attempting to change backlight fuse

Disconnect the battery first then disconnect the LVD Connector. Now connect battery again try to switch on. If its works Capacitor short on lcd backlight area(its located behind the screen ) . Usually backlight fuse will not blown itself without shorting capacitors located below the screen.

[simplylcd]

Re: Will not turn on after attempting to change backlight fuse

I have a Mac Book Pro Mid 2015 A1398 , I have the audio jack stuck in optical mode , I replaced the jack and now the stuck in optical mode is gone. The Mac Book used to chime when powered on , but now does not.

But the sound still does not work from internal speaker or jack , if I connected Bluetooth headphones the sound works , if I plug a USB-Audio adapter the sound works.

I have checked the following :

Ok was checking voltages at C6600/C6601 = 3.3v and pin 10 audio jack same , then checked back to R6322 missing board revision / R6324/R6325/C6212 all 3.3v checked PP3V3_SO_AUDIO_ANALOG =3.3v checked C6302 =1.5v fed from U6200 checked pins 1-6 as follows 1=1.5v 2=0v 3=1.2v 4=3.3v 5=0v 6=4.9v pins 1 and 3 should be 4.5v , checked capacitor C6203 connected to pin 3 and both sides shorted so removed , need to check R6200 and C6200 I think it should be 4.5v and not 3.3v I think going to pin 4 u6200


Checked all components now L6201/C6213/C6214/C6212 = 3.3v

C6216/C6217/C6218/L6201 =0v should be 3.3v traced back to audio chip (u6201) and no vref should be 4.5v but output =0v does it mean the audio chip u6201 is faulty and need replacing or u6200 that powers the chip if I feed 4.5v direct to c6213 to put 4.5v there will it damage anything ???

I have found that the power chip U6200 is not output the correct 4.5v , traced back to Pin 10 of the sound chip and no voltage out.

Is it the Cirrus Logic power amp IC or some thing else, I can only find 1 fuse on the board are there any more.


Also no the display has failed when I was checking voltages back to the LCD connector 5v feed.

It is a A1398 , 820-00138-A logic board MBP Mid 2015.

Any help would be great