New finds: enough Torch stuff to sink a battleship

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Sun Jun 29 17:00:01 2003

> > The VME interdace is a DIN41612 plug and a few buffers. AFAIK all
> > production machines had it fitted.
>
> fair call. Don't know why mine wouldn't, even if it were a prototype - if the

No idea... What (if any) chips are missing from your Stickleback, other
than the Ethernet chipset?

> circuitry's there on the card why not install the chips and sockets? Strange.
>
> > Yes, it's analoge RGB at TV rates + 2 syncs + drive for a piezo speaker.
>
> Ok. The Torch monitors I have all need seperate syncs - explains the RGB board

I thought that at least one of the monitors actually started by combining
the syncs to make composite sync (and thus you could feed composite sync
in on one of the pins). I will have to dig out the schematics...

The monitor I am thinking of is almost entirely a Sony chassis, with a
little Torch PCB at the input carrying the 8 pin DIN socket and
connectors to the monitor video board (flat in the bottom) and the speaker.

> > There's an 8 pin power connector on the stickleback. Is is connected to
> > anything other than the PSU and the battery? The touch-switch circuitry
> > is on the PSU board, and sends an interrupt over one pin of that
> > connector (I can dig out schematics/pinouts if you need them).
>
> *wanders off to check...
>
> Just PSU and battery. Connections as follows:
>
> ^- front of board
>
> GND o o +5V
> GND o o +12V
> BATT o o -5V
> +5V o o nc
>
> v- rear of board

I think that 'NC' pin is for the interrupt input from the touch switch.

>
> The battery is obviously wired to ground too. 12V from the PSU also runs to the
> battery via a lot of black insulation tape; I haven't looked what's under there
> yet...

If it's like the production PSU, little more than a diode and a resistor
in series... Watch out -- if the NICd goes open-circuit, then the clock
chip might end up getting 12V....

> Yep it is - says so on the board :) I have the manual for the Xebec interface
> to which it plugs into and that's definitely SASI / ST506. There's not much to
> the SASI board as it turns out - see earlier post; most of it turned out to be
> comms circuitry for driving the modem and nothing to do with the drive
> interface. Far as the SASI side of things is concerned, it's just some octal
> buffers, latches and the like; only about ten LSxx ICs.

One question? Is there a ROM or EPROM on this board connected to the 1MHz
bus side of things? The reason I ask is that there's some feature of the
BBC micro where you can get it to execute code from a ROM in one of the
1MHz bus address spaces after a reset, if you hold one of the interrupt
lines low or something. I wonder if that's where it gets the hard disk
drivers from...

The Torch _SCSI_ interface just has a normal sideways EPROM (SCSIFS) in
one of the Beeb mainboard sockets, BTW...

> >> I do have a spare hard disk labelled as Quad X, those tape drives and
> >> controller boards, a surplus Torch-stock PSU, complete ROM set, and the
> >> complete schematics for the QX VME card. I'll just go build myself
> >> one... ;-)
> >
> > Good luck in finding that custom chip (oh, what did they call it?) that
> > handles video, etc...
>
> the Openchip? True. I do have the programming guide and the spec (which I

That's the one...

> believe you said that you had), but unfortunately not the chip. I bet the guy I

YEs, I think i have some data on that somewhere. I also have _one_ of the
chips, in the QuadX board.

> got this stuff from has a whole pile of them!

If so, try to grab them :-)

> > The Manta is something I know nothing about, so if you have technical
> > docs I'd be interested in probing you for information...
>
> yep, I do - no schematics though :-)

Argh!

-tony
Received on Sun Jun 29 2003 - 17:00:01 BST