Macbook a1466 issues

[ohspecial1]

Hi Folks

I have 3 of these lousy macbook air 2017 models

1st 1 did have a light but no more

this was the readings before i lost charge light

PPVRTC_G3H should be 3.3v is 2.7v

R6125-R6120 BOTH MISSING

R6121 + R6126 BOTH MISSING OR REMOVED

RTC_RESET_L – 2.7V

PCH_SRTCRST_L-2.7V

PCH_INTVRMEN_L-2.7V

PCH_DSWVRMEN_L-2.66V

PP3V3_S5= 3.3V

PM_DSW_PWRGD-3.37V

PP1V8_S3= 0V

PP1V2_S3=0V

 

[2informaticos]

First of all, welcome to the forum!

Be sure all SPI Bus Series Termination resistors are in place and have good traces.
What is exact PPBUS_G3H voltage?

Resolder U1900 first; you may need to change it.
Reball SMC, if you note corrosion near it.

 

[ohspecial1]

Hi no voltage on ppbus_g3h checking on the fuse

3.3v on pp3v42

i will check

I will also look as i have 3 of these with 3 issues

 

[ohspecial1]

Hi
Have removed u1900 was 2 pins short on there via solder bridge just wondering if to buy a replacement or refit it

 

[2informaticos]

Resolder it and post its voltages.
Also post diode mode to ground at C7140.
If no short, check U7100 basic voltages; 1, 2, 3, 9, 12, 13, 14, 15, 17, 19, 20, 27.

 

[ohspecial1]

thx i will check just have to order a replacement as all the legs fell off lol

any idea on the 2 other a1466

They are both intermittent work sometimes

 

[2informaticos]

Did you open new thread with other A1466?

 

[ohspecial1]

No i havent opened any other yet

 

[2informaticos]

Please don't put more than one board in a thread.

 

[ohspecial1]

Hi
Have redone the u7100 hopefully its soldered ok not my strongest point using hot air on ics

Nothing on ppbus

c7140 is a dead short

 

[2informaticos]

So you have short to ground on PPBUS_G3H?
What is exact ohm resistance?
Remove F7140 and check which side the short remains.