Good Day!
History:
The board was not booting, upon opening it the fan was spinning but there is no PPVCC_S0_CPU. PP1V05_S0 was 0.550v. PP1V05_S0 Diode Mode = 0.007v , Resistance = 3.4ohm. ALL_SYS_PWRGD = 3.340v. I suspected it was a short on the PP1V05_S0, so I lifted L7630 and found the 3.4ohm short on the Load Side. I injected 1v on the rail and it was only taking 34mA. After this I returned L7630 and investigated the U7600 (TPS51916). It has VREF (1.8v) and REFIN pins. And sure enough, the REFIN voltage is just 0.550v. That is why there is ALL_SYS_PWRGD, because it thinks it is doing its job. So, I measured the Voltage Divider resistors for the P1V05S0_FB. R7612 is out of spec. I removed it but then it was measuring correctly (50.1kohm). So I returned R7612 and removed U7600. Short on the PP1V05_S0 rail was gone. I soldered a new TPS51916, powered it on and now I'm getting 1.055v on PP1V05_S0. PPVCC_S0_CPU is also at 1.702v. Fans are spinning.
Problem: No Chime, No POST
Status:
Magsafe = Green to Orange LED
Fan = Spinning
Image = None
Backlight = None
USB Mouse = No LED
Caps Lock = No LED
Shift + Power = Fan turns off
SMC Reset = Fan turns off while holding keys and starts again on release
PRAM Reset = No Response
Board is very pristine.
J6100, U6100, U1900 are very clean. Traces are good too.
Tested SPI Termination resistors, all match value from the schematic.
Probing SYSCLK_CLK32K_RTCX1, I get ~32kHz
Voltages (I'm sorry if this is too much, I just want to put out as much information):
PPBUS_G3H = 8.58v
PP3V3_S5 = 3.343v
PP5V_S5 = 5.101v
PP3V3_SUS = 3.342v
PCH_INTRUDER_L = 3.115v
RTC_RESET_L = 3.359v
PCH_SRTCRST_L = 3.354v
PCH_INTVRMEN = 3.248v
PCH_DSWVRMEN = 3.251v
S5_PWRGD = 3.368v
PM_DSW_PWRGD = 3.406v
PM_BATLOW_L = 3.356v
PM_RSMRST_L = 3.315v
PM_PWRBTN_L = 3.403v
SMC_ONOFF_L = 3.413v
PP3V3_S4 = 3.336v
PP5V_S4RS3 = 5.104v
PP3V3_S3 = 3.341v
PP1V8_S3 = 1.800v
PP1V2_S3 = 1.202v
PP5V_S3_RTUSB_A_F = 5.104v
PP5V_S0 = 5.098v
PP3V3_S0 = 3.339v
PP1V05_S0 = 1.050v
PP1V5_S0 = 1.506v
P5VS4RS3_PGOOD = 3.339v
P1V8S3_PGOOD = 3.340v
DDRREG_PGOOD = 3.340v
P1V05S0_PGOOD = 3.341v
ALL_SYS_PWRGD = 3.346v
CPU_VCCST_PWRGD = 1.019v
CPU_VR_EN = 1.053v
PPVCC_S0_CPU = 1.700v
PP0V6_S0_DDRVTT = 0.600v
CPU_VR_READY = 1.051v
PM_S0_PGOOD = 3.410v
PM_PCH_PWROK = 3.410v
CPU_VIDALERT_L = 0.098v
CPU_VIDSCLK = 1.050v
CPU_VIDSOUT = 1.050v
SMC_DELAYED_PWRGD = 3.406v
PM_PCH_SYS_PWROK = 3.409v
LPC_PWRDWN_L = 3.343v
PLT_RESET_L = 3.344v
PLT_RST_BUF_L = 3.336v
EDP_PANEL_PWR = 0v
SMC_LSOC_RST_L = 3.397v
SMC_MANUAL_RST_L = 2.812v
SMC_RESET_L = 3.370v
PM_SYSRST_L = 3.337v
CHGR_RST_L = 3.378v
SMC_CPU_VSENSE = 1.698v
SMC_P1V05S0_VSENSE = 1.055v
PP1V05_SUS = 1.058v
Is the EDP_PANEL_PWR supposed to go up after the POST? PPVCC_S0_CPU should also be 1.85v? What should I test for next? Thank you in advance!
History:
The board was not booting, upon opening it the fan was spinning but there is no PPVCC_S0_CPU. PP1V05_S0 was 0.550v. PP1V05_S0 Diode Mode = 0.007v , Resistance = 3.4ohm. ALL_SYS_PWRGD = 3.340v. I suspected it was a short on the PP1V05_S0, so I lifted L7630 and found the 3.4ohm short on the Load Side. I injected 1v on the rail and it was only taking 34mA. After this I returned L7630 and investigated the U7600 (TPS51916). It has VREF (1.8v) and REFIN pins. And sure enough, the REFIN voltage is just 0.550v. That is why there is ALL_SYS_PWRGD, because it thinks it is doing its job. So, I measured the Voltage Divider resistors for the P1V05S0_FB. R7612 is out of spec. I removed it but then it was measuring correctly (50.1kohm). So I returned R7612 and removed U7600. Short on the PP1V05_S0 rail was gone. I soldered a new TPS51916, powered it on and now I'm getting 1.055v on PP1V05_S0. PPVCC_S0_CPU is also at 1.702v. Fans are spinning.
Problem: No Chime, No POST
Status:
Magsafe = Green to Orange LED
Fan = Spinning
Image = None
Backlight = None
USB Mouse = No LED
Caps Lock = No LED
Shift + Power = Fan turns off
SMC Reset = Fan turns off while holding keys and starts again on release
PRAM Reset = No Response
Board is very pristine.
J6100, U6100, U1900 are very clean. Traces are good too.
Tested SPI Termination resistors, all match value from the schematic.
Probing SYSCLK_CLK32K_RTCX1, I get ~32kHz
Voltages (I'm sorry if this is too much, I just want to put out as much information):
PPBUS_G3H = 8.58v
PP3V3_S5 = 3.343v
PP5V_S5 = 5.101v
PP3V3_SUS = 3.342v
PCH_INTRUDER_L = 3.115v
RTC_RESET_L = 3.359v
PCH_SRTCRST_L = 3.354v
PCH_INTVRMEN = 3.248v
PCH_DSWVRMEN = 3.251v
S5_PWRGD = 3.368v
PM_DSW_PWRGD = 3.406v
PM_BATLOW_L = 3.356v
PM_RSMRST_L = 3.315v
PM_PWRBTN_L = 3.403v
SMC_ONOFF_L = 3.413v
PP3V3_S4 = 3.336v
PP5V_S4RS3 = 5.104v
PP3V3_S3 = 3.341v
PP1V8_S3 = 1.800v
PP1V2_S3 = 1.202v
PP5V_S3_RTUSB_A_F = 5.104v
PP5V_S0 = 5.098v
PP3V3_S0 = 3.339v
PP1V05_S0 = 1.050v
PP1V5_S0 = 1.506v
P5VS4RS3_PGOOD = 3.339v
P1V8S3_PGOOD = 3.340v
DDRREG_PGOOD = 3.340v
P1V05S0_PGOOD = 3.341v
ALL_SYS_PWRGD = 3.346v
CPU_VCCST_PWRGD = 1.019v
CPU_VR_EN = 1.053v
PPVCC_S0_CPU = 1.700v
PP0V6_S0_DDRVTT = 0.600v
CPU_VR_READY = 1.051v
PM_S0_PGOOD = 3.410v
PM_PCH_PWROK = 3.410v
CPU_VIDALERT_L = 0.098v
CPU_VIDSCLK = 1.050v
CPU_VIDSOUT = 1.050v
SMC_DELAYED_PWRGD = 3.406v
PM_PCH_SYS_PWROK = 3.409v
LPC_PWRDWN_L = 3.343v
PLT_RESET_L = 3.344v
PLT_RST_BUF_L = 3.336v
EDP_PANEL_PWR = 0v
SMC_LSOC_RST_L = 3.397v
SMC_MANUAL_RST_L = 2.812v
SMC_RESET_L = 3.370v
PM_SYSRST_L = 3.337v
CHGR_RST_L = 3.378v
SMC_CPU_VSENSE = 1.698v
SMC_P1V05S0_VSENSE = 1.055v
PP1V05_SUS = 1.058v
Is the EDP_PANEL_PWR supposed to go up after the POST? PPVCC_S0_CPU should also be 1.85v? What should I test for next? Thank you in advance!
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