This is a bare PCB for a ROM Board that is compatible with the Acorn System Computer.
The only option for fitting EPROMs to Acorn System
computers is the single socket on the CPU Board or the two sockets provided on
the 8K RAM/8K ROM Board, they never produced a ROM only board, the only other
option is to use the Control Universal CUMEM Board. I do find though that I am regularly swapping out EPROMs
e.g. to switch between COS / DOS or BASIC extension ROMs so decided to make a
board that would hold several EPROMs with front panel switching to select what
you wanted. So this board has ten EPROM positions and I also managed to
fit in an 8K RAM !
There are four rotary switches on the front panel that
can select the EPROM/RAM for each of the four 4K banks at C000 to F000 as
follows:
-
S1 selects between two EPROMS at F000 (Banks 1 and 2)
e.g. COS and DOS
-
S2 selects between two EPROMS at E000 (Banks 1 and 2)
e.g. NFS
-
S3 selects between three EPROMS (Banks 1 to 3) or RAM
(Bank 4) at D000 e.g. BASIC Floating Point Extension or ONLIBASIC
-
S4 selects between three EPROMS (Banks 1 to 3) or RAM
(Bank 4) at C000 e.g. BASIC or ADE
The board only accepts 2532 EPROMS and not 2732 (sorry
but that's what I tend to use on all my machines).
I have a range of replica or compatible PCBs available, mainly for the early Acorn System Computers range but also for the later Atom, BBC and Master computers as well as many Econet components and some early SC/MP based items e.g. the MK14 Computer.
Not all of these boards may be in stock, if you wish to buy an out of stock board drop me an email and I will reorder.
Further details can be found on my website, including all the Schematics and BOMs (Bill Of Materials).though you'll have to search for it because I can't put a link here - try 'acorn system computers website'.
I will combine postage on multiple items, please ask for a total before paying as I cannot combine postage after you have paid !
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