820-00165 no boot

wgaca

Member
Originally there was damage on Y1905, U3510 and C7540. Very isolated damage.
Nothing looked corroded, just cleaning the liquid stains (probably had sugar) was enough to see that the parts were not visibly damaged.

I will post the measurements, but keep in mind that I already tried replacing Y1905, U1900 and I checked with another bios to ensure that's not the issue.

PPBUS_G3H - 8.58V
PP3V3_S5 - 3.3V
PP5V_S5 - 5V
PPVRTC_G3H - 3.3V
PP3V3_TBT_LC - 0.5V

SYS_CLK_CLK25M_X1 - 0.6V-0.7V
SYS_CLK_CLK25M_X2 - 0V

RTC_RESET_L - 3.3V
PCH_INTVRMEN - 3.2V
PCH_INTRUDER_L - 3V
PCH_SRTCRST_L - 3.3V
PCH_DSWVRMEN - 3.2V

PP3V3_SUS - 3.3V
SPI_MLB_IO3_HOLD_L - 3.3V
SPI_MLB_CLK - 3.3V
SPI_MLB_IO0_MOSI - 3.3V
SPI_MLBROM_CS_L - 3.3V
SPI_MLB_IO_MISO - 3.3V
SPI_MLB_IO2_WP_l - 3.3V

PM_SLP_SUS_L - 3.3V
PM_SLP_S5_L - 0V (Pulsing on start)
PM_SLP_S4_L - 0V (Pulsing on start)
PM_SLP_S0_L - 0V (Pulsing on start)

PP3V3_S4 - 0.34V (Pulsing on start)
PP3V3_S0 - 0V (Pulsing on start)
PP5VS4_RS3 - 0V (Pulsing on start)
PPVCC_S0_CPU - 0V (Pulsing on start)

I figured many rails are present for a second on charger connect while writing this post.
Is there any way I can find what is causing it to pulse without measuring every capacitor on the board for short?

Resistance to ground:

PP3V3_S0 - 2.2k
PP5V_S0 - 3.6k
PPVCC_S0_CPU - 8.4 ohm

The board takes 0.02 Amps when connected to a power supply with a MagSafe cable.
 

2informaticos

Administrator
Staff member
Be sure all SPI Bus Series Termination resistors are good, as their traces too.
Clean/remove J6100.

Do you get pulse at pins 7 & 3 of U1950?
 
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