820-00239-09 - A1706 continues chime sound

Removing J501 I could see the fans running, starting with low speed and keep increasing to high speed, No other difference.Battery connectors also removed, Doesn't made any change.
 
SMC_LSOC_RST_L stays high (3.9V).
BUF_SMC_RESET_L - This I couldn't measure Because the test points are located on bottom layer where I don't have access when the board is mounted
 
Let me elaborate a little more ,

When I power up its goes to two different scenarios
Scenario1- it goes to loop with a chime sound. When it is in the loop I can see there is the backlight.
Scenario 2 - When I try to start No backlight, Slowly CPU heat increasing and the fan works after some time.
 

2informaticos

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Check CPU core voltage in both scenarios.
Disconnect devices one by one and try to identify if boots, but not looping.

Did you try PRAM reset?
 
One more input - I have a strong feeling that scenario 1 and scenario2 are related to temperature. If the heatsink is hot it doesn't go to loop. Or else it goes to loop.

Regarding the PRAM reset - I could hear only one chime when I press all four keys, Keep waiting for the second chime but it's not happening. But I could feel the heat on the heatsink.
 
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