I am working on MacBook 12" A1534 2017 820-00687-B assuming that the logic board is same as 820-00244-B. It was not powering on. I did a ultra sonic cleaning of the motherboard since I saw some traces of liquid spill. Tested out of the casing, all worked fine & display was working 100% well. When I installed it again, no display. So I again was removing the logic board & while removing the keyboard connector I saw little smoke off the connector. I started to check the voltages again. 3.3volts is perfect but 5 volts rail fluctuates on & off on coil L7670 (PP5V_S4)., 5V come & goes again. I did not find any short to ground on this rail. Any tips or guidance will really be appreciated. Thanks in advance.
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MacBook 12" A1534 2017 820-00687-B
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Re: MacBook 12" A1534 2017 820-00687-B
Ok 'mon2"., on the EN1 pin of U7650 (PM_SLP_S5_L) the voltage toggles on & off, even on pin 7 & 8 same thing voltage toggles.. But EN2 (S5_PWR_EN) pin 21, here the voltage is constant 3volts, this is why I am getting the 3.3v perfectly. Next to check I think "PM_SLP_S5_L" from where it genereating or some rail. Please inform me.. Thanks
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Re: MacBook 12" A1534 2017 820-00687-B
The CPU may be defective as reported by more seasoned techs on this forum but hate to believe it. It is a show stopper of an issue if true.
Our fancy BGA rework station should land next week and we are looking forward to complex repairs like CPU rework / reflowing. Has multiple HD vision cameras to perfectly align the balls once we clean the drop site.
2) What is the voltage on PM_SLP_S5_L ? nearly 2.9 & then drops
What is the voltage reading once this rail settles ?
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