I don't have an 8300 here but web8201.net has some detailed technical docs. Here is a page describing the PROM as 128k
http://web8201.net/NEC8201emulation.asp Kurt -----Original Message----- From: M100 [mailto:[email protected]] On Behalf Of Stephen Adolph Sent: Friday, February 17, 2017 2:53 PM To: Model 100 Discussion <[email protected]> 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 > >
