Re: Unitron EPROM writer?

["Mark Cummings" <NOTfigjams@primus.com.au>]

> Good advice!  I thought about trying this the other night -- after I had
put
> away the machines with convenient slot access!  Well, I tried again
tonight
> in a IIe that I have.  The card wasn't getting recognized in slots 3, 4,
or
> 7.  Then I hit paydirt in slot 2!  I think it has to do with whether I had
> the card turned on or off during bootup (yeah, the card has an on-off
> toggle!  Crazy).

My card has an ON/OFF toggle and matching LED, but that is used to turn on
the programming voltage to the EPROM for burning them, nothing to do with
disabling the card. To read EPROMs the swith stays OFF.

>  I think I need to flick the card on while the machine is
> booting - if I leave the card in the "on" position before booting, it
> doesn't actually come on.  If I want too long to turn it on, it doesn't
get
> recognized.

Strange

> Anyway, when I do pr #2 and get into the software, all I get is a very
> simple screen (but hey, at least it's a screen!!).  It says:
>
> EPROM WRITER USE PR#1-PR#7 ROM SIZE:
> 2708=1 2716=2 2732=4 2764=8
> ROM SIZE?

This is basically all they do, so I think that is all you need. funny that
it says PR#1 to PR#7 and only works in slot 2. maybe it is conflicting with
other cards. I have discovered by accident that mine doesn't like my AHS
card.

> If I hit "?", I get a little menu:
>     1) WRITE
>     2) READ
>     3) COPY
>     4) MON
>
> Hitting 4 drops me into the monitor.  I haven't played too much with the
> other options, but they seem to be very particular about the memory
regions
> that you are interested in reading/writing/copying.

normally you drop into the monitor so you can access the disk drive for
reading and writing data which is stored in regular RAM. That's why you need
to boot a DOS/ProDOS disk first otherwise you have no way to save your data.
OK, except for the tape routines in ROM :)

> I think that the four sets of numbers refer to 4 empty sockets on the
board,
> numbered "08", "16", "32", and "64".  They are 14 pin sockets, but are
quite
> distinct from the large EPROM socket (which has an open/shut lever, kind
of
> like a ZIF socket on a PC motherboard).  There are other populared 14 pin
> sockets, but I don't think they are related to these empty ones - I can
> transcribe their markings, if that sounds interesting.

Sounds like your burner uses a 14 pin header socket (dongle) which is
plugged into the appropriate 'type' socket to get the right voltages to the
right pins on the EPROM ZIF socket. you WILL need that bit to get it to
work. They should be easy enough to make, but you will need advice from
someone who has that exact model so you can copy the dongle. Most likely
it'll have a 14 pin header and a few jumpers or resistors, maybe with a
plastic hood.

There is one other way to make this dongle but it would require analysing
the circuit board to see where the tracks go between the ZIF and the 14 pin
'type' sockets. or in other words a circuit drawing. If you can't find a
someone with the info you are after I may be able to help, but at the very
least I would need a closeup scan of the card from both sides showing the
ZIF and the empty 'type' sockets.

Mark