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If 3V3_S3 is present then 5V_S3 should be there too. The enable for both comes from SLP_S4, 5V_S3 enable is inverted by Q7911. Measure voltages on Q7911 and Q7221.
There is not a short on the 5v_s3 rail. In diode mode 5v_S3 is showing 0.153v.
In voltage mode I get 0.18v on 5v_S3 and 5.02v on PP5V_S5.
Resistance to GND on ENTRIP1 is 78.6 kohms
I have already replaced U7200 and that didn't fix the issue. Actually before replacing U7200 a couple of days ago I was getting 2.55v on 5V_S3 and 5V_S0.