On Thu 01 Oct 2020 at 15:18:40 +0200, Francesco Messineo wrote: > PCB #320008 (the first 2001 released) has no empty ROM sockets. It > uses MPS6540 ROMs that are 2Kx8 each. > I have seen quite a few of them (and I own a 2001 with this motherboard). > There are other 2001's PCB revisions that use 2316 ROMs, I have never > seen one of these, but the schematic seems to imply they didn't have > any empty ROM socket too. It has been a while since I was at the computer club at school (1980 to be precise), where we had old-ROM PETs with the built-in cassette, but I was sure that they already had free ROM sockets. But looking at zimmers.net pub/cbm/schematics/computers/pet/2001, I could find no sign of that. I have here just a board 320132, which on zimmers.net described as "Schematic 320130 for assembly 320132 with 6540 roms and 2114 ram". Somebody has removed all ROMs in the H row from it before it got to me. It has 7 ROM sockets, indeed not enough to have spares if each socket contains 2 KB. > 2001N have $Bxxx, $Axxx and $9xxx empty ROM sockets (or just $Axxx and > $9xxx if one installs basic 4). The 2001N PCB uses 4Kx8 ROMs with a > single 2Kx8 one at $Exxx socket. On the other hand, in .../computers/pet/2001N/320349.pdf for example there are 3 spare ROM sockets. Maybe we had already this model in "old ROM" configuration. -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"
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