Won't boot - no display, solid white light. Fans spin up and gets loud.

Hi Everyone,
I have a Core Duo 20" that won't boot. The display won't light up, and the white light stays on the whole time. No chime. Fans start slow, but then gradually gets very loud after over the course of a few seconds.
I've began taking it apart. One suspect area is the DC/DC Inverter board. The POWER_GOOD line is only showing 0.16V. Most power supplies uses signaling between 3V and 5V so I'm suspecious of this 0.16V POWER_GOOD signal.
Can someone help chime in (no pun intended), or verify the POWER_GOOD signal voltage of an early 2006 iMac Core Duo (2105)?
THANK YOU!
Yue

By the way, I've done AppleOption+PR (from my LCII days!), and have removed the logic board battery, waited, reinserted and retired without success. Thanks!

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http://discussions.apple.com/message.jspa?messageID=13240047#13240047
https://discussions.apple.com/message/15223603#15223603
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Won't boot - no display, solid white light. Fans spin up and gets loud.

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