Macbook pro A1278 no power with led green on magsafe

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

voltages don't change while shorting power on contacts

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

voltage here before and while and after shorting smc bypass:

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

0 volts with or without smc bypass

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

check L4901 for voltage. if present reflow smc.

check also if l4901 is not shorted.

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

i can't find L4901

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

great news! i reflowed smc with 300 degrees and flux. It turn on now!
thank you dellxps15

[ktmmotocross]

Re: Macbook pro A1278 no power with led green on magsafe

300? aint that little high for ic?

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

great news! i reflowed smc with 300 degrees and flux. It turn on now!
thank you dellxps15

l4901 marked on that picture, but really glad u fixed that macbook. u saved a lot of money

300? aint that little high for ic?

with macbook i reflow using 380-400° on my hot air station atten 8586 as macbook absorbe heat very much. ofcourse each soldering station has it's own temperature calibration.

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

i have installed Yosemithe OS, but the sound is disabled andi can't activate it because the icons are blank.

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

try a pram reset. also a smc reset.

[opethfan]

Re: Macbook pro A1278 no power with led green on magsafe

thank you

[bluestone]

Re: Macbook pro A1278 no power with led green on magsafe

I have some issue with mine too, it can't recognize the battery, I have replaced the battery, tried the power reset still not working, any ideas

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

open your own thread with model board, picture and description of problem.

[ithelp]

Re: Macbook pro A1278 no power with led green on magsafe

making measure all around the board without a logic is no sense. this big thing with all 0 volt is lan filter..... useless to measure for now.

i asked for 2 measure on these 2 coils (inductor) in my previous post.

next report voltage on green zone.

total 2 measure+ 1 ground.

u should have on green spot (white fuse) 12.5 volt ;
3.42 on the other green marked area.

if u have 3.3 volt on coil, u have 12.5 volt on that green marked fuse, and if u have 3.35 or higher (not over 3.42) u can put a fan, some ram slot, lvds connector with lcd and short that circled 2 dot on mainboard with a wtezer (smc bypass) and see if macbook start normally.

before all that, make sure u understand that procedure right. shorting those 2 pins should make your macbook start, so put fan, ram ecc ecc and be carefull to not short anything else. put all component on a non conductive zone.

u can try with magsafe only,with battery only , and with both.

any throuble, ask before act.

hi
there on my Macbook pro no voltage on fuse and tune on pad (points)
Please advice me how i check further.( and near dc jack one fuse is giving voltage.)

[dellxps15]

Re: Macbook pro A1278 no power with led green on magsafe

Forgot to say that macbook was repaired by solder a wire to bios that had broken pad under it.

For ithelp better open another thread so we all can help .and also provide board code as 820-xxxx