a1278 emc 2351 bios needed ,

[highpulse]

Re: a1278 emc 2351 bios needed ,

well it worked turned on 2 times but VERYYYY STRANGE .. it turned on only by cheking values on TPS51125 , specially after meausuring pin 16 and pin 17 , it simply turned on , after that disconnected and tryed to connect it by shunting g3hot pads , but nothing happen , so ok , i cheked pins and noticed also that if no keyboard ribbon attached i got 3.40 on the EN0 pin of tps51125 ,
once i insert the ribbon cable , there is no longer EN0 values , as also it will not turn on in any way ..

meanwhile , i removed the tps51125 and reinserted a new one (brand new) sudently i just touched the VREG5 pin and i noticed i add 5 volts .. cheked vreg 3 , also 3.3 volts . ok made the shunt on G3hot pins and machine turned on ... now let me chek if machine turn on also with the keyboard ribbon added.
Well with the ribbon keyboard cable , machine loose the Vreg voltages to 0.60 volts , and not turning on , also g3hot stay on 1.66 volts , if i remove the keyboard ribbon , machine have correct vregs and turn on once i shunt g3hot pins
i guess its a shorted keyboard

[highpulse]

Re: a1278 emc 2351 bios needed ,

ok problem on keyboard or on off button , inserted te outher keyboard on this machine and on this machine the g3hot stay ok , with the outhe rkeyboard and turn on the machine .
thk for the help guys . any help or thing you need just let me know

[dellxps15]

Re: a1278 emc 2351 bios needed ,

cool, so problem fixed

congratz

new keyboard wont be a problem ( u can first try with ultrasonic) but a new one is about 65€ship included.

for the tps51125 i suspect u had cold solder, so old chip could be also good

[highpulse]

Re: a1278 emc 2351 bios needed ,

yes guess maybe a cold joint meanwhile they looked all fine , something got wrong for sure , about keyboard well client (store) will buy and replace , our job is done here thk mate once again


all the best

[dellxps15]

Re: a1278 emc 2351 bios needed ,

Really happy that all is working. It was a pleasure to do my Little. For a MacBook repair u can easly ask 150 250€ For repair if c2d or i5 i7 . I boufht many MacBook For practice as they are complicated in throubleshoting.

[highpulse]

Re: a1278 emc 2351 bios needed ,

yes im thinking in buying some lots for repair to learn more about mac repair thk for the help once again

[izzzzzz6]

Re: a1278 emc 2351 bios needed ,

Good work guys. This board seems similar to mine, i might try the board view to see if i can trace back my problem. I'm still looking for the 820-2565-A view for 2009 13" pro. What year was this board?
Thanks

[izzzzzz6]

Re: a1278 emc 2351 bios needed ,

The closest thing i could find to my blown fuse is not a fuse on this board but a diode which could be used as a fuse i have a white fuse which is blown near the display port but this board has D9701.
Seems to be a backlight power supply but on my machine everything has gone dead, no fans but i do have battery charging and charging led's seem to be working. If my fuse is also for a backlight then why would it have blown along with the rest of the boards power?