This thread being Xerox 16/8, I am having documentation problems with a recent 16/8 purchase that came with the Expansion Module (EM-II?...Xerox ID metal chassis tag shows product code is F89). I can find little to none in documentation, so detailing in hopes of expanding the knowledge base.
Assembling the system yields "Rom Error", with failure to initialize (no beep at power on, just this printed error message. Located the error message in the 820-II BIOS code, but that's about all. I suspect the switch settings may be wrong on one of the following cards below. There is a 2732 EPROM inside the EM-II chassis, perhaps an option ROM that is not getting read. Disconnecting one of the cables to the EM-II chassis allows the system to initialize and beep "OK".
This EM-II product had a fairly short life cycle before Xerox backed out of the product line. Mine has multiple problems I need some help with. (Did Xerox ever get to the Documentation phase on this project? Did they release it? Maybe RANK Xerox in Italy, France or the UK?)
-There is the interface card that plugs into the smaller expansion connector of the 820-II board (8086 slot).
*there is an 8 position dip switch at U-3 that I need to verify is set correctly, BUT no schematic or documentation on this card. The card number is 140P83074A
DipSw on my card is set with 8=on, all others=OFF
(This is the card that the 2 long cables plug into that interface to the rear of the EM-II chassis. The bus connector on the
main CPU card is the same one that the 8086 card would plug into).
-There is no schematic found of the circuit card inside the EM-II chassis that the cables plug into.
*There is yet another DIP switch on this circuit card that the cables interface to...need to verify settings.
(My DipSw at U14 is set switches 3 and 8 = ON, all the rest=OFF)
(Board number = 140P83147A) This board also contains a PAL or 2, a 2732 EPROM, a 40 pin SASI interface, a 50 pin
header (?), header to interface to a 5 slot bus that the 8086 plugs into.
-My Shugart model 712 ST-506 HD (11Mb) powers up, then powers off squealing.
The disk controller is a stand alone 5.25" form factor WD 1002-05G capable in hardware of supporting 3 st-506 drives and 2-4 floppy drives (probably 2).
I have seen descriptions of 1HD+1FLoppy, but not a 2 Floppy setup (there is only room for 2 half height devices in the alloted space in the drive bay). FYI, My floppy is a Shugart SA455-3AA, DS/DD (verified works on an IBM XT.) (Will verify the WD Disk controller works on a Kaypro 10).
Questions I seek to answer:
-What is that 50 pin header for on the EM-II board?
-Will the BIOS actually support more than one ST-506 device connected to the WD1002-05G controller board?
(Chassis ribbon cable openings on the back of the chassis)
-How many floppies can be supported via the WD controller? 1,2,4?
-What other cards were developed for adding into the 8086 5-slot bus?
-Is the ROM code for the EM-II circuit board archived somewhere so I can check the checksum on the one I have?
-There are 2 10-pin headers on the cable card that plugs into the CPU box 8086 slot (the ribbon cable card). J3 and J4.
What is their purpose?
-With the 5.25" floppy residing in the EM-II chassis, will the standard 820-II floppy controller card with 1797 floppy controller chip driving dual 8" drives still work with the EM-II?
Unrelated to the EM-II (but not totally off topic):
Anyone have an elegant ram upgrade daughter card for the Xerox 8086 CPU card? A Xerox version or an adaptation, or am I looking at wire-wrapping up a plug-in 128K memory card?
Any help or comments are appreciated.