I'm putting together another SE/30 reloaded and populated it to the point where it should chime. However, I'm getting absolutely no activity on the address bus when scoped at the CPU. The symptoms are a simasimac image and no chime of any kind because the CPU isn't walking the address bus and executing ROM code. Troubleshooting steps I've taken:
I did make a stupid booboo when powering this board on for the first time. I put the 32Mhz oscillator in a makeshift socket for reasons and that socket didn't have anything under the little plastic standoffs on the bottom of the (grounded) metal oscillator body. This allowed the 5v metal pin socket hole to touch the oscillator body, shorting 5v to ground. The trace going to the oscillator's 5v pin (above L14 in the picture) burned up, breaking continuity between L14 and L13 and cutting power to the oscillator. I found the problem with my nose and restored continuity:
But, since that was the first time I powered up the board, I don't know if the current problem was caused by that mistake or already present. Did I fry something, or did that trace act like a fuse?
What should I be looking at that could cause no address bus activity when the CPU isn't in reset, isn't halted, and has a clock signal?
- checked every PLCC pin for continuity
- checked for shorts between adjacent pins (solder bridges)
- checked for shorts between adjacent vias
- tried 3 different CPUs
- replaced all of the PALs with newly-programmed ones
- verified CPU /RESET line is high
- verified CPU /HALT line is high
- verified CPU has a clock signal and power
- checked voltages
- stared at the board for a long time
I did make a stupid booboo when powering this board on for the first time. I put the 32Mhz oscillator in a makeshift socket for reasons and that socket didn't have anything under the little plastic standoffs on the bottom of the (grounded) metal oscillator body. This allowed the 5v metal pin socket hole to touch the oscillator body, shorting 5v to ground. The trace going to the oscillator's 5v pin (above L14 in the picture) burned up, breaking continuity between L14 and L13 and cutting power to the oscillator. I found the problem with my nose and restored continuity:
But, since that was the first time I powered up the board, I don't know if the current problem was caused by that mistake or already present. Did I fry something, or did that trace act like a fuse?
What should I be looking at that could cause no address bus activity when the CPU isn't in reset, isn't halted, and has a clock signal?