Ah, OK; we know that there are four 32KB ROM pages (plus one 32KB Option ROM slot); if the ROM0 socket is 32 pins then that (plus Kurt's reference) would suggest that everything is in one 27C1001 EPROM (with presumably a second 28 pin socket for the Option ROM.)
Unfortunately at this time I don't have any 27C1001s or the means to program them easily, so I'm afraid I can't help after all; hopefully someone else can help out. Sorry Fred, m ----- Original Message ----- From: "Stephen Adolph" <[email protected]> To: "Model 100 Discussion" <[email protected]> Sent: Friday, February 17, 2017 5:52 PM Subject: Re: [M100] Parts for an NEC PC-8300 > from my perspective- > > * there is a single socket ROM0 for the main ROM > * ROM1 is for option roms. > * there is no other ROM in the unit. > * it is a 32pin socket, and so it must be no larger than a 64kB rom. > Not likely to be 32kB. > * i'd bet that OUT163,2 sets A15 on the socket. > * no idea what the pinout is but it could be deduced quickly. I think > since the PC8201 uses normal pinouts, so too does the 8300. > > So my bet would be a 27C512 would do it. It is possible however that > it is still just a 32kB rom. Perhaps OUT163,2 sets a signal on the > PIO or otherwise that the processor can check, to decide what mode it > should be in. > > Steve > > > > On Fri, Feb 17, 2017 at 4:19 PM, Frederick Whitaker > <[email protected]> wrote: >> Mike >> >> There are places for two ROMS. In the regular PC-8300 there is only one ROM >> used for Basic. >> 83100 - 438 >> N83A Basic >> 1986 >> Microsoft >> 8649 - Z69 >> >> In the other unit, which no longer has it's regular ROM, there are two ROMs >> D276256D-20 >> D276256G-25 >> >> I hope this helps. On the PC-8300 there is a wide access on the back with >> three screws. Only two ROM sockets are visible and usable without >> dismantling the case. >> >> I hope this helps. >> >> Fred Whitaker >> >> >> On 2/17/2017 2:15 PM, Mike Stein wrote: >>> >>> Looks like it's up to you, Fred: >>> >>> Can you open up the 8300 and tell us exactly how many and what kind of >>> ROMs or EPROMs are in there, i.e. any labels and/or part numbers? >>> >>> Since at least one is custom firmware it's probably in an EPROM (as >>> opposed to a ROM) and will probably have a standard number like 27C512. >>> >>> From what I've read it looks like there should be three 28-pin sockets >>> with a 27C512 in two of them and the third one empty or with an Option ROM >>> in it. >>> >>> Let me know what you find. >>> >>> m >>> >>> ----- Original Message ----- >>> From: "Fred Whitaker" <[email protected]> >>> To: "Model 100 Discussion" <[email protected]> >>> Sent: Sunday, February 12, 2017 3:32 PM >>> Subject: Re: [M100] Parts for an NEC PC-8300 >>> >>> >>>> Mike >>>> >>>> I don't have an image. I don't know if the ROM you are referring to will >>>> do the job. The 8300 ROM is bigger than the 8201, but I believe it uses >>>> the same chip as the 8201. >>>> >>>> I was under the impression that someone had uploaded a copy of the 8300 >>>> ROM contents, but I don't remember where or when. >>>> >>>> I could send you one of my ROMs, from another machine, but I don't know >>>> if that would help. >>>> >>>> Fred Whitaker >>>> >>>> On 2/11/2017 7:48 PM, Mike Stein wrote: >>>>> >>>>> Hi Frederick, >>>>> >>>>> If you can send me or point me to an image of that ROM I can probably >>>>> burn an EPROM for you, assuming it's a JEDEC-standard 27xxx type. >>>>> >>>>> m >>>>> >>>>> ----- Original Message ----- >>>>> From: "Frederick Whitaker" <[email protected]> >>>>> To: "Model 100 Discussion" <[email protected]> >>>>> Sent: Saturday, February 11, 2017 6:27 PM >>>>> Subject: [M100] Parts for an NEC PC-8300 >>>>> >>>>> >>>>>> I am interested in a replacement keyboard for my NEC PC-8300. I also >>>>>> need a new Main ROM, When I received this machine it had a specialized >>>>>> ROM in it. It will not boot. >>>>>> >>>>>> If I had those two items I could use this machine. I have asked in the >>>>>> past if anyone could make a main ROM for this machine but never >>>>>> received >>>>>> an answer. >>>>>> >>>>>> Fred Whitaker >> >>
