Gradius II board problem

[VectorGlow]

I have a Konami Gradius II (Vulcan Venture) boardset that goes through the usual 'RAM ROM CHECK' routine then comes up with:

ADDRESS ERROR

PC 00034DF9

D0 00000000 A0 7357305A

with various results all the way down to D7 and A7

Trouble is that I simply cannot figure out what is causing this - RAMs and ROMs are fine, support chips APPEAR to be fine (but most of them are the dreaded Fujitsu TTLs so that doesn't bode well), no apparent shorts or track breaks, all sockets are good, etc.

The fault is definitely on the main CPU board.

Any ideas please? Maybe if I had a 68000 pod for my Fluke I could socket one (or both) of the 68000s and do a bus test, RAM and ROM tests, etc. But I don't, so I can't.

 

[cliff_poole]

I don't have any suggestions I'm afraid but I do have a working board and a 'scope if you would like me to check anything ?.

I soo wish I had a 68000 pod too, bus faults on 68000 boards are a complete nightmare. Once, I did managed to track down an address bus fault on a Gauntlet board using a 'component tester', attachment on a 'scope (works the same way as a Huntron tracker). It turned out to be a slight scuff on the underside of the pcb causing a bit of resistance between two tracks.

 

[VectorGlow]

Thanks for the offer, I'll have another prod at it in a few days and give you a yell if need be.