vinaypundith
New member
I have a 2017 13" MacBook Pro motherboard (model 820-00840-A) that won't turn on. I measured the PPBUS_G3H line with a USB-C charger connected, and get around 1.08V (instead of 12V?). No short to ground in this line - resistance measures 1K ohms rapidly increasing to infinity.
Fuses F3000 and F3100 are both intact - I resistance tested them. However when I test for PP20V_USBC_XA_VBUS (or the one for the other port) at either F3000 or F3100's terminals, I get zero volts at all. Measuring between ground and either of F3100 or F3000's terminals, I get a 22.8 ohm continuity. Is this a short to ground? How would I find this short? I see there are some adjacent capacitors, one of those?
I probed for PP20V_USBC_XA_VBUS at other adjacent points (including L3300 and L3400 solder pads - my board apparently never had these components) - no voltage at all.
Other nearby voltage rails I probed: USBC_XA_CC2 (and CC1 and CC1/2_CONN) fluctuating between 0.8 and 1.5V, SAVE_CC1A no voltage at all.
Anyone know what's wrong? Thanks in advance!
Fuses F3000 and F3100 are both intact - I resistance tested them. However when I test for PP20V_USBC_XA_VBUS (or the one for the other port) at either F3000 or F3100's terminals, I get zero volts at all. Measuring between ground and either of F3100 or F3000's terminals, I get a 22.8 ohm continuity. Is this a short to ground? How would I find this short? I see there are some adjacent capacitors, one of those?
I probed for PP20V_USBC_XA_VBUS at other adjacent points (including L3300 and L3400 solder pads - my board apparently never had these components) - no voltage at all.
Other nearby voltage rails I probed: USBC_XA_CC2 (and CC1 and CC1/2_CONN) fluctuating between 0.8 and 1.5V, SAVE_CC1A no voltage at all.
Anyone know what's wrong? Thanks in advance!