For reference I tried another motherboard on 1 address line and got a more better result on the same settings, so I think pulse view can see ok

treeman wrote on 2023-06-10, 01:06:

https://i.ibb.co/cYMn65G/6th.png […]
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You have to zoom all the way in at the start of the sequence.
>D5 = pin 20
>D4 = pin 22

Now we can see there is D4 D5 activity after all
We know board is not starting so obviously there wont be continuous access. We are interested in seeing if there is an initial attempt to read bios - 5 byte access at FFFF0h. What can be happening:
- no activity at all, cpu might not be running at all
- few initial bytes are fetched but bios/motherboard databus is corrupted and computer immediately crashes

Ok I tried the clockgen chip now to see how good the multimeter was.

Looks like you were right rasz, shows signals on 8mhz 25mhz and 33mhz

8mhz

25mhz

33mhz

D7=Refclk

So like you are saying good chance a data line from bios to chipset or from chipset to cpu or worst case chipset itself is losing the information.
No pinout for this chipset also available.

However it has been great to learn new things here, and as always im not writing it off for the 50th time ill check chipset pins and try trace a few data lines etc

maybe oneday ill stumble onto a replacement chipset too