Date   : Tue, 20 Feb 2007 23:43:12 +0000
From   : hideki.adam@... (adam colley)
Subject: Some Beeb addons

Hihi

On 20/02/07, Kris Adcock <beeb@...> wrote:
[Snip]
> There's a Computer Village LVL DOS board, labelled "CVX7 Disc
> Interface". The controller on it is an FDC 1797, and there's a ROM
> marked "LVL DOS 1.00". How does this compare with the more usual 8271 or
> 1770 interfaces?

That's a double density DFS board, you can format disks to 10 or 16
sectors per track using the format commands in the ROM, I do not
believe it's 1770 compatible but it was so long ago I can't say for
certain (my school had those)

> There's a Computer Village sideways ROM board, with sockets for 16 ROMs
> - that can't be right, can it? There is also a row of 15 jumpers, each
> of which can be set north or south. Anyone know what they are for? Also,
> the 6502 processor and ULA are held on this board - the boards connect
> to where they should be on the main board. Is this just to make the
> board secure, or is the board doing something special that requires
> these ICs moving?

Got one of those

You don't need to change anything to remove it, it has 16 sockets
because it replaces the 4 sockets on the board.

The jumpers on mine are set to:

Reading from the left with the battery at the top left:

up, up, up, up, off, down, up, down, down, up, up, up

on mine the two sockets at the top left (the two to the right of the
battery next to each other marked Page &06 and &07) are populated by a
pair of 6264 chips to give you 16K of sideways RAM

removing it should be a case of moving the Basic and LVL DOS roms to
the usual 4 sockets and moving the 6502 and ULA back to the normal
places, that's all I had to do on mine, no jumpers or links to
set/clear

> Does anyone have scans of the docs for these items? The Beeb isn't
> really working properly (it never gets to a prompt - just makes a
> constant beep tone) and I'd like to remove them to clean the machine and
> help narrow down where the fault is - but I'm not sure about what
> jumpers I'd need to change on the board when I remove the ROM board.

No docs sadly although this one is surplus to requirements (it doesn't
work with GoMMC) so should your sideways rom board be dead, I can send
this one to you if you want it

I'd suggest reseating the chips, I'd then check the PSU (with a meter,
under load), possibly the 6522 chips, they are at least socketed so
you can shift them from a working machine temporarily to test them.

-- 
Hideki.Adam