Very interesting notice El mié., 17 jul. 2019 15:23, Stephen Adolph <[email protected]> escribió:
> Kurt, no problem at all. You've done some nice work to accomplish this. > Very cool. Steve > > On Tue, Jul 16, 2019 at 11:26 PM Kurt McCullum <[email protected]> wrote: > >> I wanted to give my thanks to Stephen Adolph for tracing down the bank >> selection pin on the NEC main board. After some testing and a small bit of >> soldering I can confirm it works. For mine I have SARDOS on Bank 1 and >> UR-2 on Banks 2&3. >> >> For those interested in this modification the instructions are below. >> >> 1) Solder a wire to the underside of pin 15 on U53. You will need a >> couple inches of wire. I used AWG 26 wire. >> 2) Replace the 27C256 32k EPROM with a 27C512 64k EPROM. The lower 32k >> will be the EPROM for bank 1 and the upper 32k will be the EPROM for banks >> 2 & 3. (I have the binary image if anybody wants to make one) >> 3) Bend pin 1 of the 27C512 EPROM out so that it wont go into the socket. >> 4) Solder the wire from U53 to pin 1 of the 27C512 EPROM. >> 5) Insert the EPROM into the socket making sure pin 1 is clear >> >> Cold start the machine and you now have 2 ROMs to work with, each with >> it's own bank of memory. Enjoy. >> >> Thanks again Steve! >> >> Kurt >> >
