820-3115 slow boot then stalls

[tlough75]

I have on the bench an 820-3115 that came in as not booting. when I opened it up to check things I noticed the hard drive was clicking, so I assume it is dead. Well A few times I turned it off and on and noticed when I plug in the MS the light stays green and the computer actually turns on. Is it supposed to do that? I have my own working machine and when I plug in the MS it does not turn on or fans spin.my question to this is are these machines supposed to do that? The other problem was the fan was spinning on high and it looks like it is going to boot but gets stuck. I checked the DC-IN and U7000 Resistances and they are 20.2 ohms and 3 ohms, which is normal. Should I be suspecting the ME? I have tried a new HDD and cables and nothing changed.

 

[tlough75]

Well not sure what I have done but it seems to be working now. I tried first a PRAM reset and then an SMC reset. An additional weird thing it would do is turn on even when I plugged in a USB device (External SSD). The SMC reset seemed to have fixed that issue. the Magsafe light also now goes from green to orange, showing it is charging the battery. Also, the fan is no longer spinning on high. All I have done was removed the board for bench testing, and tried to do an SMC Reset. I am able to turn it off and reboot to a test HDD to show that the cable is still ok. So it looks like the customer will have to replace the HDD only.

 

[2informaticos]

Any iCore MLB starts by itself when charger is connected, if no battery present.

SMC reset is needed only when main battery is present.
Once battery and charger are both disconnected, SMC_RESET_L signal goes low automatically.
This happended whrn you remove the board from case; not needed to did that.