Re: Unitron EPROM Writer UPDATE

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

Hey Mark!!

Thanks so much for this great information.  I will look at the component
side of the Unitron and try to get you this information as soon as possible.
I have to head out the door just now, but wanted to thank you for the effort
and report that my IIgs network is amazing fun!  Just wish I had more time
to play with it!!  That's the good thing about winter coming up - lots of
evenings indoors.  Heh heh... :)

Cheers!
Tim

"Mark Cummings" <NOTfigjams@primus.com.au> wrote in message
3bd2c91c@news.iprimus.com.au">news:3bd2c91c@news.iprimus.com.au...
> Tim,
>
> I have been working on those scans to draw out some kind of circuit
drawing.
> While the back is pretty easy to follow, I'm afraid it's impossible to
> follow the tracks on the component side without actually having the board
in
> hand.
>
> Unfortunately while that close up scan does make it easier to read the
IC's,
> it's still pretty hopeless trying to see where those tracks go in the
> shadows or under chips.
>
> So far I don't have enough of the circuit to come to any conclusion, but
if
> you can trace (follow) some of the tracks on the component side that may
> help. I assume you know how the chips pins are numbered. If you can remove
> the chips temporarily that may help, just keep a note of where they go and
> which way. Also that ZIF might get in the way, my AP-64e EPROM programmer
> has a socketed ZIF so I can pull it out, the Unitron one appears to be
> soldered onto the board.
>
> this is what I need to fill in some of the gaps:
> where do the following tracks go to (if they exist) on each of the
following
> ?
> (BTW if the track goes to a passive component, like a resistor or
capacitor,
> forget that and keep following it to a chip leg if applicable). Some may
go
> to a few places.
>
> 1. Socket 08 pin 1, 5, 6 & 12
> 2. Socket 16 pin 3, 11 & 12
> 3. Socket 32 pin 2 & 3
> 4. Socket 64 pin 1, 3 & 6
> 5. ZIF Socket pin 2, 26, 27 & 28
> 6. 7406 pin 1, 3 & 7
>
> Although I can't see these can you confirm the following:
>
> (A9) ZIF pin 24 - 4040 pin 14
> (A8) ZIF pin 25 - 4040 pin 12
> (A7) ZIF pin 3 - 4040 pin 13
> (A6) ZIF pin 4 - 4040 pin 4
> (A5) ZIF pin 5 - 4040 pin 2
> (A4) ZIF pin 6 - 4040 pin 3
> (A3) ZIF pin 7 - 4040 pin 5
> (A2) ZIF pin 8 - 4040 pin 6
> (A1) ZIF pin 9 - 4040 pin 7
> (A0) ZIF pin 10 - 4040 pin 9
>
> I'm still working on the theory that the header will be wired as:
> 1-14
> 2-13
> 3-12
> 4-11
> 5-10
> 6-9
> 7-8 (although I'm not sure if this last connection is used)
>
> The chips you need were:
> 7406 - quad NAND gate Open Collector (don't use any other type or the
smoke
> will get out)
> 74LS74 - dual D Flip Flop +ve edge triggered.
>
> I am not sure why +12V is supplied from the Apples bus pin 25, unless the
> programmer also programs 12V EPROMs. Most older EPROMs were 21-24V. This
> might complicate the issue, although I'm hoping if you can supply some or
> all of the above answers it might become clear.
>
> BTW: Congratulations on getting the GS networked to your Win2K PC, I bet
> that has taken your fun to new heights, and this little EPROM project will
> probably take a back seat for a bit.
>
> Mark
>
>
>