Uni, did you try the IIsi using the Vampire Video for the test? If, so slap a Pivot card in there, unhook the cable from the onboard connector and test again.

Done that way, you ought to have a much better chance of it working.

edit: I finally put the probes onto the memory pins of both banks and MDU.

MoBo powered down:

_____74ALS245 buffers at rest

__________Bank_B_pin_4_A0 -> MDU_pin_70

__________Bank_A_pin_6_A0 -> MDU_pin_69

So Bank A Addressing is indeed separate from Bank B Addressing with the buffering ICs in this state.

Can I safely add power from an outside source to the 74ALS245 bus buffer ICs to test the other two states? Individually or separately? Alternately, I could remove de-solder/isolate/power up the VCC leg of the appropriate 74ALS245 a/o DRAM IC? Most radical approach would be to desolder the and 7fALS245 and build a test circuit board with an old school 74LS245?

edit: Does anyone have a link to such a DIY bus testing circuit board, such would be a tremendous help in ferreting out the address and control lines for the 2300c and 1400 for the Video and PCMCIA hacks. [] ]'>