Imac not turn on - 820-2494A

Incopia2

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#1
Motherboard 820-2494A
Problem = Not turn on, no work.
Signals cheked:
All signals about power, SMC_ONOFF_L, LID singnal, VCC, AVCC and vref to SMC, and a lot signals about power init.
All Oscillators about SMC, 32,768khz, MCP 25Mhz, and 20mhz osc...
Power supplies about boot secuence. 1.1v - 3.42v - 12v...

all signals even the oscillators seem to be fine, I have decided for a small difference in some signals controlled by the SMC, because they had small voltage differences, and some small oscillation.

I tried first to heat the smc, but it has not worked, finally I have rework the smc and it has worked, I had serious doubts about smc and mcp because the signals with small diferences are shared.


WhatsApp Image 2018-08-24 at 13.31.49.jpeg

WhatsApp Image 2018-08-24 at 13.40.16.jpeg
 
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