820-4924 with corrosion around U3220 and U3320, no Magsafe LED or boot. I replaced those ICs and got the unit to boot fine, but without keyboard or trackpad. While testing, I did not have the fan attached. Before I could start troubleshooting the KB/TP issue, I had to go take what I thought was going to be a short phone call. I forgot to disconnect from power and the board ran fanless for over 90 minutes. When I came back, it was pulling about 10ma and missing all S4 and lower rails including PM_SLP_S4_L. The behavior was mimicking the symptoms in this other thread, so I followed the same troubleshooting steps... https://boards.rossmanngroup.com/threads/820-4924-missing-pm_slp_s4_l.57094/
Bottom line is that it appears to be a dead PCH. I haven't tried heating the PCH with flux applied, not sure how to do that without affecting the CPU in a negative way.
Did I fry this thing by running it without a fan for 90+ minutes? I would have assumed that the CPU would have throttled down according to heat sensor input.
Don't feel too badly for me, this is a board from an eBay machine I bought to practice on, so I'll just consider it a learning experience if it ends up being a dead PCH.
Bottom line is that it appears to be a dead PCH. I haven't tried heating the PCH with flux applied, not sure how to do that without affecting the CPU in a negative way.
Did I fry this thing by running it without a fan for 90+ minutes? I would have assumed that the CPU would have throttled down according to heat sensor input.
Don't feel too badly for me, this is a board from an eBay machine I bought to practice on, so I'll just consider it a learning experience if it ends up being a dead PCH.
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