ENSONIQ DP/4 - Random attenuation on Data lines

[StEeLz]

Hi Gang,

I am trying to troubleshoot an old Audio equipment with no boot / no display symptoms. So far I have found one dead RAM chip.
However, I am still finding some weird behaviour on the MC68B03P I/O pins.
As you can see on the pictures attached, I have some weird and random attenuation that doesn't seem right.
Some High signals are peaking at 3.6V, and some others are at 5V as expected. I have traced the signal and removed all the surrounding components to only leave the CPU and the 2 EPROMS.
I have swapped the CPU for multiple variants, and tested the EPROMS, everything seems to be OK, yet I'm curious.
If those attenuated signals seem to be within specs, what would cause this?
Looking forward to your thoughts!
Cheers

[m k]

Lower picture has something I'd say is faulty, those that are not coming down and 3,6V is a bit high for high impedance.
Overall shapes should also be more retangular.

Have you just tested those ROMs and not changed them?