G4 logic board question

[John McGibney]

The logic board fried on my G4 tower. Its the 400mhz gigabit ethernet model.
I'm hoping somebody here knows what circuit fried so it doesn't happen again
if possible. The fried components are labeled C1559, C1562 & C1570. They
appear to be related to the AGP slot as best as I can tell.

I replaced the stock ATI card with an ATI 8500 card. If the video card is
bad I don't want to fry another board if I can help it. Any experts know
what's up? I can send pix if needed.

TIA
John