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NEC APC IV - an early 286 PC

dhau

dhau

Experienced Member
Joined
Feb 13, 2018
Messages
323
Location
Toronto, ON, Canada
I recently bought NEC APC IV 286 PC running at 8 or 6MHz. I've dumped the BIOS, so people can use it to fix their computers. This BIOS is very similar to IBM PC AT 5170. If I remove WD1002-WA2 floppy/MFM controller card, it starts complaining about "Disk controller failure".

PhoenixBIOS-v1.57-1986-opt.jpg

View attachment PhoenixBIOS 286 v1.57 1986.zip

I ended up replacing the original BIOS with PhoenixBIOS A286 1.01 from minuszerodegrees.net. Now I can boot from an IDE HDD and use built-in BIOS setup.
 
tipc said:
APC III & IV are some of the grooviest peecees. I never had a IV and I'm jealous. But let me ask this, does the Mobo use a chipset?
Click to expand...

I can see three Chips and Technologies chips, but can only read one, the others are under drive bays. The one I see says P82A204.

If I understood the Wikipedia article on NEC PC-9801 series right, APC IV is the export version of domestic NEC PC-9801 VX.
 
I picked up a couple of these recently. I need to power them up and see if they work. One has a seagate ATA/XTA compatible drive in it, that I’m going to liberate and hopefully use on my Compuadd 810. I’ve get the utility floppies for diags and running setup, if you wanted to run the original BIOS. I can send you images of them.

0A5F8E32-1797-4CE0-AE56-674D95C8CF75.jpeg
 
@jafir: Please and thank you! I would love to get the setup software. My box looks much bigger though. Please check what version of BIOS your boxes have. Mine was 1.57 from 05/13/86. The date time is clearly seen even in split roms near the end of the file.

Here is how my APC IV looks. Sorry about front panel and case, I'll take another photo once I put it together.

NEC APC IV 1024 opt.jpg
 
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That looks to me like a PC AT clone, not a member of the PC9801 line, which uses C-Bus expansion cards and isn't remotely hardware compatible with a 5170.

The 9801VX C-Bus expansion bay can be seen here. The EGA card pictured above is for an ISA bus machine.
 
Speaking of EGA, the owners manual for mine show the monitor that goes with it, called the “advanced color monitor” or something like that, and it’s an original NEC multisync. I picked one of those up too, but it’s “dead” and has no stand.
 
Chuck(G) said:
That looks to me like a PC AT clone, not a member of the PC9801 line, which uses C-Bus expansion cards and isn't remotely hardware compatible with a 5170.

The 9801VX C-Bus expansion bay can be seen here. The EGA card pictured above is for an ISA bus machine.
Click to expand...

Of course it's an IBM PC AT clone. No one would buy some weird incompatible system in North America. However I'm pretty sure most chips are shared between early NEC APC IV 286 and PC-9801 VX.
 
There should be 360K images in that archive too. I believe they have the same contents.
 
The cards, and all functionality of the original APC (built in crt) was on the cards, were nearly the size of multibus. The APC III used c-bus for ancillary functions. Mine has the 8087, sound and SLE compatibility contained on cards. Most of the computer proper was on the motherboard.
 
Chuck(G) said:
I don't know--I've never seen any.

But the APC 1 original was, in fact a real C-Bus machine, so properly a member of PC98 clan.
Click to expand...

dhau said:
Of course it's an IBM PC AT clone. No one would buy some weird incompatible system in North America. However I'm pretty sure most chips are shared between early NEC APC IV 286 and PC-9801 VX.
Click to expand...

Lol tell that to all the people who bought Tandy 2000s, TIPCs, Sanyo MBCs, and NEC APC IIIs, and the list goes on for some time.
 
At my first job out of Uni I used to support SCO Xenix 286 on APC IV's with Stallion multiport serial cards in them, running our company's Project Home Building cost-estimation software (written in RM Cobol).
I don't recall having any problems with them at all (apart from Xenix uucp being flaky, so what's new) and they were quality machines. The company was in financial trouble and was acquired by the second company I worked for, which was doing Windows 2 and 3 programs and the old Xenix and RM stuff and piles of hardware was chucked. I ended up with a Unisys 5000/50 (NCR Tower) as well, wish I still had that. I am sure I still have the Xenix 286 floppy install set somewhere, I know I still have a Xenix 86 set.
 
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I discovered yesterday that my wide APC IV from 1986 won't work with most VGA cards with 64KB BIOS, i.e. two 27256 chips. It looks like the second half of VGA BIOS is "under" the system ROM BIOS. This affects ATI VGA Wonder XL24 for example.

One card with 64K BIOS worked after I used the switch settings to put it into a basic VGA mode - Headland VRAM 2 (HT209 chip).

All my single BIOS 32K chip cards worked fine, but they have slower BIOS, running in 8-bit access mode.
 
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