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First of all, welcome to the forum!
I can't say to much, if you didn't tell us which kind of software problem noted on the machine.
Flashing BIOS and replacing SSD will erase any kind of "persistent memory" from the board.
You may have corroded traces, or components in backlight area.
As I said, backlight control comes from LCD assembly, through I2C bus.
If you see PWM activity from PCH, then the problem is between LCD and U8400.
Put some logic on your work.
I said all AWAKE and SLPS2R voltage have been confirmed; as you was able to see the machine in DFU mode!
However, is your choice, if you like to waste time checking them again.
You didn't check exact points expected for SSD voltage; but enough to see all missing...
Did you check with red probe at ground?
If PWM works, then you should have activity on I2C backlight bus too.
If not, there is a problem with LCD assembly, video connector, or U8400.
Did you try another small video cable with other LCD assembly?
"Post voltage and diode mode..."
With charger alone, the board turns on and restarts in few seconds?
Be aware, this board requires 85W charger to start (without battery).
SMC_RESET_L steady high?
Did you try SMC bypass ?
I really don't understand why do you insist to post Q7030 all pins voltage.
I asked about ONE voltage point (F7040).
If you like to waste time, is your choice.
So you get incorrect PPBUS_G3H voltage, 12.13V; no matters battery is connected, or not.
That means bad communication between SMC and...
"i removed the video card"
What this means?
The GPU is soldered on the MLB, there is no video card.
It can be disabled, as already posted on the forum.
Did you change C9560 before?
"Post F7040 voltage w/ and w/ battery connected."
If you've posted ONE voltage only, does this mean is the same...