KC Micro Tronix
Member
I was given a box full of MacBook board by one of my customers. They are boards that 'ALL" have been worked on "some brutally" by someone. I have fixed half a dozen of them or so and basically learned what I was doing on them. This weekend I was caught up on my work so I went digging in the "toy box" for something to do. Often I go back to boards I could not figure out a few months ago only to figure them out now that I have more experience but this one has me stumped. It is a 1.8G 8G board so I am really motivated to figure it out. I am currently out of these boards and need some badly.
Here is what is was doing when I first got my hands on it. "It would turn on for about 10 or so seconds "pulling lower than normal current 275mA instead of the usual 450-550mA" then it would shut off. The previous tech had bypassed SMC_DELAYED_PWRGD on U1950 by bypassing it so they could get PM PCH SYS PWROK out of the and gate. They ran a jumper from pin 6 of U1950 to pin 5 so PM S0 Good would complete the "AND" gate on U1950. I undid this do discover the PM PCH PWROK signal was not present.
I re-flashed the bios and this did fix this problem. I now get a PM PCH SYS PWROK out of U1950 with out it being hot-wired! I was excited but... Current draw is still lower than normal 275mA and after about 10 seconds or so it does power off again and cycle just like it did before I removed the hacked "And" gate.
The CPU never sends the EDP_PANEL_PWR signal to the display section.
Am I kicking a dead horse here? I really don't know where to look from here other than a SMC or CPU and I really don't want to go there and smoke another hour.
I would appreciate any guidance.
Here is what is was doing when I first got my hands on it. "It would turn on for about 10 or so seconds "pulling lower than normal current 275mA instead of the usual 450-550mA" then it would shut off. The previous tech had bypassed SMC_DELAYED_PWRGD on U1950 by bypassing it so they could get PM PCH SYS PWROK out of the and gate. They ran a jumper from pin 6 of U1950 to pin 5 so PM S0 Good would complete the "AND" gate on U1950. I undid this do discover the PM PCH PWROK signal was not present.
I re-flashed the bios and this did fix this problem. I now get a PM PCH SYS PWROK out of U1950 with out it being hot-wired! I was excited but... Current draw is still lower than normal 275mA and after about 10 seconds or so it does power off again and cycle just like it did before I removed the hacked "And" gate.
The CPU never sends the EDP_PANEL_PWR signal to the display section.
Am I kicking a dead horse here? I really don't know where to look from here other than a SMC or CPU and I really don't want to go there and smoke another hour.
I would appreciate any guidance.
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