I have checked my old notes for the 2001. The original 2001 has no empty sockets for additional ROMs, but there is a connector on the right side of the computer for bus expansion. That does have selector lines for expansion ROMs. If you have the version with the 2316 ROMs, there is a modification that will allow you to put expansion ROMs on the circuit board. The ROMs are selected in 4K banks, even on the original 2001. Two sockets are selected in each 4K bank, except $E000. The 2316 ROMs are wired to respond either to the upper or lower half of each bank. You can replace the two 2K roms in one bank with a 4K EPROM, in either socket. You now have a free socket. You now need to cut the bank select line for the empty socket and jumper it to the appropriate select line on the 74154 at G2. On Thu, 1 Oct 2020, Rhialto wrote: > On Sun 27 Sep 2020 at 05:46:27 -0500, vossi wrote: >> Hello, >> >> I'm very interested in option rom's for the pet2001. >> I think there's not much available because the 2001 has no option rom >> sockets! > > Huh? The 2001 motherboard had empty sockets for 4KB blocks at $9000, > $A000 and $B000, from the very first model onwards... but now that I > think of it, there were variants of the board, with 2 different types of > ROM and 2 different types of RAM chips... maybe the variant with the 2 > KB ROMs didn't have space for empty sockets? > > These ones are probably for "New ROM" (because there is a DOS Wedge > included in the description), but you can have a look: > http://www.geocities.ws/davegostelow/PETroms/PETroms.html > > -Olaf. > -- > Olaf 'Rhialto' Seibert -- rhialto at falu dot nl > ___ Anyone who is capable of getting themselves made President should on > \X/ no account be allowed to do the job. --Douglas Adams, "THGTTG" > wlevak_at_sdf.org SDF Public Access UNIX System - http://sdf.orgReceived on 2020-10-04 11:00:03
Archive generated by hypermail 2.3.0.