Looks that way; what confused me was that there are images out there (even with the Y2K adjustment) that are labelled 27C512.
m ----- Original Message ----- From: "Stephen Adolph" <[email protected]> To: "Model 100 Discussion" <[email protected]> Sent: Friday, February 17, 2017 8:26 PM Subject: Re: [M100] Parts for an NEC PC-8300 > VT simulates it with 4 rom banks. > so, .. it must be 128kB. > > I just have no idea what the pin assignment on a 28 pin socket could be. > > ..Steve > > > On Fri, Feb 17, 2017 at 8:20 PM, Stephen Adolph <[email protected]> wrote: >> ROM0 is 28 pins. I went downstairs to open it up again and count... >> can't be 27c1001. that's 32 pins as you say Mike. >> >> so, still a mystery. >> >> I thought maybe it could just be a 64k ROM - that clearly can fit in a >> 28pin socket. >> >> Steve >> >> >> On Fri, Feb 17, 2017 at 8:13 PM, Stephen Adolph <[email protected]> wrote: >>> oh that's very interesting. ok. I wonder what the pin assignment is. >>> >>> what does the 8300 need 96k of rom for 8300 mode for, vs only 32k rom for >>> 8201? >>> >>> a schematic would be golden. All I can say is there is no other ROM >>> on the board. >>> >>> Steve >>> >>> On Fri, Feb 17, 2017 at 6:51 PM, Kurt McCullum <[email protected]> >>> wrote: >>>> 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 >>>>> >>>>> >>>>
