J4105 boot problem

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   My J4105 (fw 1.40) has a strange behaviour at the boot.
The first time I boot after a prolonged poweroff time, the board shutdowns before the beep and just before "Press F2.... etc".
If I press the power button again, everything is fine.
If I reboot from inside the os (Win10-64), everything is fine.
If I shutdown the system, disconnect the power cord for a couple of minutes, connect it again and then power on the board, everything is fine.
But if that pause becomes 10 minutes, the problem appears again.
I suspected a psu related problem, so I tested with another psu, no results.
I made a ClearCMOS, no fix.
It seems as a capacitor need to be charged first, but the board is new and there's no cap with evident signs of failure.
Any idea?

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mmassimo Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04 Jul 2020 Status: Offline Points: 4	Post Options Post Reply Quote mmassimo Report Post Thanks(0) Quote Reply Topic: J4105 boot problem Posted: 05 Jul 2020 at 12:33am
	My J4105 (fw 1.40) has a strange behaviour at the boot. The first time I boot after a prolonged poweroff time, the board shutdowns before the beep and just before "Press F2.... etc". If I press the power button again, everything is fine. If I reboot from inside the os (Win10-64), everything is fine. If I shutdown the system, disconnect the power cord for a couple of minutes, connect it again and then power on the board, everything is fine. But if that pause becomes 10 minutes, the problem appears again. I suspected a psu related problem, so I tested with another psu, no results. I made a ClearCMOS, no fix. It seems as a capacitor need to be charged first, but the board is new and there's no cap with evident signs of failure. Any idea?

NNEERR Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 30 Sep 2018 Status: Offline Points: 20	Post Options Post Reply Quote NNEERR Report Post Thanks(0) Quote Reply Posted: 08 Jul 2020 at 7:08am
	It's not clear to me what "poweroff time" means. "Soft off" or "Mechanical Off"? If it's "Mechanical Off" it's the behavior of this board also at me (where I don't know if this is works-as-designed or just a strange behavior; I also don't like it!). I think it is PSU related if it is about "Soft Off". It seems the PSU doesn't provide the necessary power to the board when switched off ("Soft Off", state G2/S5, see https://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface#Global_states). Maybe it provides enough power only for around 10 minutes (e.g. by a filled cap or so). BTW: My boards are working fine with internal DC/DC boards (like "Pico PSU") and my external AC adapters (Inter-Tech cases with included DC boards).

mmassimo Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 04 Jul 2020 Status: Offline Points: 4	Post Options Post Reply Quote mmassimo Report Post Thanks(0) Quote Reply Posted: 11 Jul 2020 at 8:51pm
	Thank you for your reply. For poweroff I mean power cord disconnected. So your board has the same behaviour as mine, it seems something by design. I've to correct my first post. When board shutdowns, it happens just before the beep. I performed a test with a PicoPSU, but I got the same result as with ATX psu.