Hello,
Working with an 820-00165 that has green light/orange light, fan spin, and boot chime but no display. Connecting to an external monitor works and the blinking folder shows up on the external monitor. F7700 has 8.57V on both sides but PPVIN_S0_SW_LCDBKLT at pin 1 of L7701 is 0V. PPVIN_S0SW_LCDBKLTFET going to pin 4 of Q7706 is 8.57V. BKL_EN at U7701 is 0V. PP5V_S0 at U7701 is 5.128V and PP3V3_S0 is 3.4V.
I'm thinking that there may be a short to ground based on getting a small tingle while resting my arm on the chassis and taking a measurement. The short might then be causing U7701 to not turn on the display. However, I can't find the short anywhere on the board. Nothing is extremely hot. Aside from measuring component to component, is there a good strategy for finding a short that would affect the display?
Steve
Working with an 820-00165 that has green light/orange light, fan spin, and boot chime but no display. Connecting to an external monitor works and the blinking folder shows up on the external monitor. F7700 has 8.57V on both sides but PPVIN_S0_SW_LCDBKLT at pin 1 of L7701 is 0V. PPVIN_S0SW_LCDBKLTFET going to pin 4 of Q7706 is 8.57V. BKL_EN at U7701 is 0V. PP5V_S0 at U7701 is 5.128V and PP3V3_S0 is 3.4V.
I'm thinking that there may be a short to ground based on getting a small tingle while resting my arm on the chassis and taking a measurement. The short might then be causing U7701 to not turn on the display. However, I can't find the short anywhere on the board. Nothing is extremely hot. Aside from measuring component to component, is there a good strategy for finding a short that would affect the display?
Steve