820-01598 not booting but has power

[bdawg]

Hello, any help with this is greatly appreciated as always. This board has power but is missing ppvccgt_cpu_ph1 and ph2. The board is taking 20v / 450ma but has no chime, no video. Fan spins and CPU and surrounding components heat up. Resistance on L7410 and L7420 both read 2.8 ohms. I don't have another one of these boards so I am unsure if that is normal. And basically 0v on those. All other rails seem fine. Any suggestions from here?

Thank you so much everyone

[piernov]

Re: 820-01598 not booting but has power

https://logi.wiki/index.php/User:Pie..._I_solve_it.3F

[mon2]

Re: 820-01598 not booting but has power

For your logic board, review this power rail sequence chart:

[bdawg]

Re: 820-01598 not booting but has power

Oh I see... thank you very much for the info. I have determined I have no EDP_PANEL_PWR_EN coming from U0500 R0542 is fine. I am guessing U0500 is bad :/