v7 GH-022 dead after mod

I've got a V7/8 GH022 with a gap bios (080)

I've fitted a ripper chip and when powering on its dead. no logo. i found out if i disconnect the O wire it boots up and the logo appears. ive dedone all the wires and also tried another chip. still the same prob. also checked around the O point with a meter. no shorts.

any suggestions?

did you bridge the solder points on the ripper chip

yip.

also just tried a nh9 (the only other chip i've got lying around) - gives the same problem.