820-3115-b restarts

[tech]

neat and clean 820-3115-b board turns on and chime sound coming, but chime sound repeats display not switching
no voltage drop found all coming continously even it chimes again and again
tried clear me but no changes.

 

[2informaticos]

Tried one RAM module at time?
Still restarts starting in SMC bypass, or safe mode?

 

[tech]

tried with different ram slotes
display not coming
only repeated chime sound

 

[tech]

also the same happens in smc bypass mode

 

[2informaticos]

Did you test the board alone on the desk?
Don't connect anything, apart of charger, speaker and USB tester.

Any history available?

 

[tech]

yes tested board with dc jack and speaker only

 

[tech]

same conditon

 

[2informaticos]

Did you clean ME on its BIOS, or tried full new (clean) BIOS?

Check if SMC_ONOFF_L is steady high.
Also check SMC_TPAD_RST_L.

 

[tech]

yes tried me bios /another working bios but same result
all voltages steady including SMC_ONOFF_L ,SMC_TPAD_RST_L.
I changed smc still same condition

 

[2informaticos]

Check PCH's RTC signals if steady.

 

[tech]

RTC_RESET_L
PCH_SRTCRST_L
PCH_INTRUDER_L
PCH_INTVRMEN_L
all remains steady and 3.3v

 

[2informaticos]

CPU core cycles?
Also monitor PLT_RESET_L.