Hello all, i have a High Speed pinball giving me problems. When i turn on the game, the all bulbs lite but no displays and no sound. Probably no cpu boot. I checked all voltages and appear to be good, unplugged all connectors and reseated, no change. When the upper diagnostics switch on CPU board is pressed, i get a test sound, when i press the lower switch i get a code 8. Any ideas how to proceed.

First of all, tx for your inputs.

Wayout:
the 5v measures 4.99 at 1j17 with no ripple and 4.92 (clean) at pin 1 of U26 /U27. The 12v measure 12.69 with .2vac. not sure if that not good.. the -12v measures -14.27 with .04vac
i checked the clock signal, its there, checked the Reset line and it goes high and stays there.
i momentarily pulse pin 40 of U15 to gnd, i get a tiny buzz sound and nothing else happens.
Question is now, whats next?

Uncivil, yes i did remove rom chips, cleaned leads gently with a small copper brush. No change.

Hey Wayout, success! all working. After doing the cpu troubleshooting and seeing what i could look at, i was able to get with local repair guy who had a High speed pinball. Plugged his roms in and cpu booted. Apparently my roms when bad. Weird, but they are 30 years old. Learned a little on troubleshooting along the way.
Tx for your inputs and time, really appreciate it. Thats why i just recently joined pinside because alot of good people on here and also knowledgeable.
Thanks again, Joe