Re: Unitron EPROM writer?

["Tim Haynes" <trhaynes@yahoo.SPAMBGONE.com>]

Mark,

Thanks for the compliment - the scans did turn out quite good, I think.
Amazing that you can read the socket designation on the empty socket under
the ZIF!  I can't even make out anything at all that from the scan, but you
hit it almost on the money - it's 74LS74.  I presume that these chips can be
bought somewhere even if they are necessary.  I didin't take them out - the
board came that way.  I think I'll scan some more boards and put them up for
people to comment on - a few of them are real mysteries to me!

If you need scans with different perspectives (perhaps good head-on closeups
of the header sockets?) just let me know.  In fact, I'll do a close up of
the header right now.

I'm going to put some new card scans up, and have set up site for them to be
viewed.  Check out:
http://hsr.dhs.org/apple2/.

Thanks for your help and advice!  I REALLY appreciate it!!

Thanks
Tim

I think
"Mark Cummings" <NOTfigjams@primus.com.au> wrote in message
3bc85fc4@news.iprimus.com.au">news:3bc85fc4@news.iprimus.com.au...
> Tim,
>
> Excellent pictures, I'll see how I go. BTW nice blue, you don't see that
too
> often in A2 circuit boards.
> Building the header will be a piece of cake, designing it... now that'll
be
> the hard (read fun) part.
> I'll post back here if I need any more info, like where the tracks go on
the
> component side, which are a bit hard to see when they dissappear under
> things.
> One thing that does worry me is the missing chip under the ZIF socket.
Looks
> like it says 74LS14 or something. Also the 7406 missing above the EPROM.
Did
> you take these out or were they missing when you got it ?
> That switch on the end definately looks like it's for Read/Write mode. And
I
> would say that red LED will come on for Write mode.
>
> Mark
>
>
> Tim Haynes <trhaynes@yahoo.SPAMBGONE.com> wrote in message
> news:HuOx7.184580$sM1.51956121@news3.rdc1.on.home.com...
> > Hey Mark,
> >
> > Okay, I finally got scans of the Unitron.  Here they are:
> >
> > http://hsr.dhs.org/~timh/UnitronFront.jpg
> > http://hsr.dhs.org/~timh/UnitronBack.jpg
> >
> > What do you think - is building a header within the skills of someone
who
> > can work a soldering iron and order parts from www.Digi-Key.com (just
got
> > their catalog in the mail.  Holy chips batman!)
> >
> > Cheers!
> > Tim
> >
> > "Mark Cummings" <NOTfigjams@primus.com.au> wrote in message
> > 3bc442b6@news.iprimus.com.au">news:3bc442b6@news.iprimus.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
> > >
> > >
> >
> >
>
>