MBP 17 A1261 Dead- No Start- Voltage Issues

[triplelucky]

Hi, Im working on an older 2008 non unibody Macbook pro 17, model A1261. I have 18.8 V to pins 7 and 8 on the logic board power connector J6990 but no voltage on pins 1 and 2.

I have no voltage to U7600 on the LIO board.

It appears that the 5V is down. I am trying to figure out where/ how the 5V is supposed to be coming from the 18.8 V

I am currently not understanding if the 5v is supposed to be being regulated from the 18.8 on the logic board and sent over to the LIO or what.

I have 3.3V on the logic board PWR ON jumper pads.

I have the logic board and LIO board out on the bench with 85W magsafe, no battery, and have no power to HD or fans etc. No response from shorting PWR ON pads.

The logic board is 820-2262-A and the LIO is 820-2274-A

Any helpful ideas would be appreciated.

Thanks