I'm having problems with an IO. My first conversion, including goo scraping,
went just fine. The second is proving to be a bit of a pain.
The system was definitely booting to the IO screen, I could get into the
BIOS, etc. before I started scraping.
I got all of the goo off. It looks clean. Nothing. Not even the power-light-
always-on that seems to indicate "BIOS chip not there."
I took a voltmeter and started prodding around the power circuitry starting from
the 19V in. I'm comparing the V3 (nonfunctional) to a functional V1. There is
definitely 19V coming onto the board, and there is definitely a 19V drop across
C234 (just above the right corner of the power connector) on both systems.
What is odd is the measurements I'm getting on R253/254 (or rather, the empty pads
for 253/254), just below the SODIMM at its center.
On the functional V1 I'm getting 3.2V on the lower 2 pads and 3.5V on the upper
two pads regardless of whether power is on or off. (Reasonable, somebody has to
feed the power switch circuitry). On the dead V3 I'm getting essentially 0V
on all four pads.
Is there the possibility that I've fried part of the power circuitry?
Is anyone out there an expert on analyzing/repair at this level?