Hi people ,
I'm working on a mpu for my Embryon and now I'm stuck. When I bought the machine the mpu was completely locked up (no flicker, led lit). There was a little bit of acid damage so I got to work. I measured the 5 volt on reset on the chips so I thought the reset was okay. Cleaned up the damage, replaced all the sockets and changed a PIA and that got me a flicker on the LED, succes . Now after the flicker the led waits a while and then just turns on. So I don't get the first flash which would be a problem with the roms. I allready saw that the roms were in bad shape so had ordered them earlier. While waiting I cleaned up the pcb a bit more and made the jumper changes so when the roms came I could just pop them in and see if it worked. I've been working on it for a few days and worked very precise. Then came a new PIA and my new roms (home version 9) checked the rom type and jumpers once more. And installed, hoping it would work but ofcourse, it didn't after this I've been checking a lot of traces, continuity and looking over my work again. I can't find anything wrong.
It still gives me a flicker, pause and then a lit LED.

Does anybody know what I'm missing? Any clue what to look next for? Is there some kind of continuity chart to check roms?

Thank you all in advance

Thank you for the quick response. I checked all the voltages at the beginning. Didn't check them again after cleaning the board. I will do that and will let you know. Thank you for the guide, looks like good reading material. I allready found some stuff I haven't read before.

Problem solved! very happy with it. Thank you Atari Daze, you provided the exact document I needed. In the repair guide there is a continuity chart I needed and with this I was able to check all data lines. Found a break in an adress line. Even after I found it, it was not possible to see without measuring it. It was the pcb tunnel close to the battery terminals.