Macbook Pro 13" A1278 (Mid 2012) no signs of life

[dellxps15]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

NO STUFF for r7093, so not present.

on page 3 there is power sequence.

for me is a bad u7200 as on fase 7 you have P3V3S5_EN that on fase 7 become P3V3S5_EN_l that is present in q7220 and q7221, but on sequence 8 PP3V3_S5_REG no present on l7220, so focus on that page 66

hope that help

[pearman]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

Thank you for helping me, I hope we can figure this out

For U7200 Pin13/EN0 is master enable and it is 0.3v (VO2/PP3V3_S5_REG will be off).

Master enable signal comes from U7941, Pin03, P5V3V3_REG_EN, which is low.
And since U7941 Pin02 is low, this seems correct behavior. Back to SMC 4900 not giving SMC_PM_G2_EN signal.

I checked that Pin14 SMC_BC_ACOK on U7000 is only 2.38v, and I assume this would need to be at least 3v for correct signal to SMC?
Could this explain why SMC will not give SMC_PM_G2_EN? Or should I dismiss SMC_PM_G2_EN for now?

R5087 has 3.49v on PP3V3_S5_SMC (PP3v42_G3h), and 2.38v on SMC_BC_ACOK side..

[dellxps15]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

try replace u7000, as smc_bc_acok comes out from u7000. and replacing it will probably fix the no magsafe green light

[dellxps15]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

looks like this video is focusing on the part you need ...

https://www.youtube.com/watch?v=WYcl2ZkqNjk

watching it and it perfect suit your problem :

[pearman]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

looks like this video is focusing on the part you need ...

https://www.youtube.com/watch?v=WYcl2ZkqNjk

watching it and it perfect suit your problem :

Nice. I have made order for the chip, but it'll take a few weeks, then we see.

[dellxps15]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

wich one ? u7000 ?

[dellxps15]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

remove u7000, connect battery only and see if u have 3.3 volt on 3.3 volt coil try to turn it on and see if it works with only battery.

[fabo99]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

Hello everybody,

Perhaps you can help me.

my logicboard 820-3115-b does not start anymore. MagSafe lights green when connected, the battery will not charge.

U7000 voltage all pins okay
U6990 pin 3 has over 15 volts but should have about 3 volts right?
when I pin 3 fair the MagSafe Led goes off

what do you think is U7000 & U6990 defect

[madjid911]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

hi
my motherboard 820-3115-b is defective, f7040 = 0.30v, I changed the u70000 and l7030 but no change f7040=030V, Any ideas?

[hackintoshmalang]

Re: Macbook Pro 13" A1278 (Mid 2012) no signs of life

i have mbp a1278 core i7 (820-2936-B) ...mine is missing PP5VS3_Vo1...on pin 24 U7200 (TPS51125)...could it be because bad chip or something else?....because on pin 7 P3V3S5_VO2 is present...