Hi
When I upgraded my A4000 from the 030 to the 040 I not only had to add two extra support pins to the processor board but also set the jumper at J100 Clock90 source to 2-3 External 040 and also Jumper at J104 CPU clock source to 2-3 External. I also changed Jumper at J151 to 1-2 200NS. That support of the processor can be very important and seating is everything. Also there can be issues with the general support of the motherboard in the casing. Mucking around with differing boards does need an element of care really... so I would check all the jumpers for the various board configurations. I would also check the seating of the ROM chips.
Its just that you may think its to do with jumper settings, but by taking stuff out and putting it back in you actually cure the problem by other means. i.e. by actually seating the processor board along its full length properly. Those plastic support legs are quite important.
I had a terrible problem with a Cyberstorm earlier this year with this very same problem.
scuzz
