4638RE: [midatlanticretro] Cromemco People in the Audience?
- Dec 1, 2006Bill,
Thanks. I will let you know.
At 06:53 AM 12/1/2006 -0500, you wrote:
>The 16FDC design calls for lower density masked ROMs. As the higher density
>ROMs got cheaper, cormemco switched over to using them. The pins that are
>tied together are just unused address pins on the high density ROM. Things
>1 make sure that the "start address" switches on the ZPU are set correctly
>2 make sure that you are using the right DB25 connector (should be just a
> through cable) and that the cable to your terminal is "right way around",
> the TXD/RXD orientation of pins 2 and 3. I can never remember when you
> DCE (Data Computer Equipment) or DTE (Data Terminal Equipment). You
> only need TXD, RXD and ground (pin 7) between the computer and the
> Try sticking a NULL modem converter in the path and see if that helps.
>3 leave out everything except the ZPU, 16FDC and the 64KZ
>4 be sure the 64KZ is set to bank 0 (zero)
>5 check voltage levels on the bus
>6 gently "rock" (ease out and reinsert) socketed chips, especially TI (Texas
> Instruments) chips with tarnished pins.
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