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OK, I removed Q7330/5. Seems they are fine...

i used a new LTC3851EUD chip... For Q7330/5. I cannot find CSD5886, is there any other replacement chip that i can use?

changed U7300, now pin 11 = 12v pin 10 = 5v pin 1 = 3.3v pin 4 = 0.216v PP5V_S3_REG = 1.378v Still not working

diode mode at pin 10 = 0.525 which is the same as known good board.

pin 11 = 12v pin 10 = 0.036v pin 1 = 3.3v pin 4 = 0v R7310 pin 2 = 3.3v, pin 1 = 0.647v Q7360 pin 1 = 0.647v, pin 3 = 0.014v R7305 ohm value = 7.6k (increasing and steady at 7,6k) but on known good it measured 15.41k issue?

diode mode to ground at L7320 = 0.07, a good known board has value 0.092 which basic voltages should I target for U7300?

PM_SLP_S3_L = 3.3v PPDDR_S3_REG = 0v PPVTT_S3_DDR_BUF = 0v PP3V3_S3 = 3.3v PP5V_S3_REG = 0v

L7920 = 1.1V When trigger SMC_ONOFF_L, PM_SLP_S4_L went from 0v to 3.3v and stay at 3.3v PP12V_S0 is also missing.

LED601 on. Checked SMC_ONOFF_L toggle 0v/3v but board does not respond. problem with SMC?

PP1V5_S0_AUDIO_DIG = 1.5v PP3V3_S0 = 3.3v PP4V5_AUDIO_ANALOG = 4.5v

sorry to dig up this old thread. I have changed the U6201 but it still the same...

unknown history.. minor corrosion around C4314/L4310, also C7524 and then some unknown liquid residue around C7623/Q7520.. I cleaned them off with alcohol. C7042 which is around U7000 seems to have corrosion around it...I have replaced C7042 and it seems to be ok now.. let me do some more testing..

without battery, when 1st plug in, I can hear the chime but screen is black and the fan will spin up for 5 seconds before it repeat, when it repeats, I hear no more chime. when plugged a battery, it will boot up, sometimes normal speed and sometimes very slowly, and it wont charge the battery...

Replaced R7052 and it is all good now. Thanks for the help.

ya i know from schematics R7050 + R7051 + R7052 should be 2.21ohm.. let me get a new multimeter, as now it is measuring 10.x ohm.. There is a glue blob around R7052 but I saw brownish shadow within it near R7052 pin2 .. when I cut open the glue blob I confirmed that pin 2 of R7052 was probably...

17/18 = 20 ohm 27/28 = 21.1 ohm

SMC_CPU_VSENSE = 0.65 - 0.95 fluctuate SMC_CPU_ISENSE =0v SMC_GFX_VSENSE = bouncing 0 - 0.7v SMC_GFX_ISENSE = 0v TP_SMC_P1V5S3_ISENSE = 0.27v SMC_CPUVCCIO_ISENSE = 0v TP_SMC_SA_ISENSE = unknown test point location SMC_DCIN_VSENSE = 2.82v SMC_DCIN_ISENSE = 2.1v and when lifting multimeter it will...

L7510/20 = 0.9v after 10s. L7550 = 0.44v at that time. machine did stay on in SMC bypass, PP3V3_S5_AVREF_SMC = 3.3v even when the fan stopped spinning..

R7402 is good and its traces and solder to pin 2/U7400 are good too. SMC bypass mode = fan stay on, USB storage has LED on too.

Q7550 pin 4 is connected to U7400 pin 12, when both are on the board, they seems to be shorted to ground(9 ohm). L7550 = 0V when on power. with Q7550 removed, the pin 4 solder pad have no short and when measure voltage it pulses.