Re: EPROM Programmers AP64e MPC APEP and YKH128

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

hi Wayne,

> Hi Everbody,
> I have three EPROM programmers I could use a little help with.

sorry to hear of your 3x EPROM Programmer woes. hope this will at least help
you get your AP64e going:

> 1) an AP64e dosen't seem to work. replaced all small chips and 6821 with
> good ones. NO dice so, Breadboarded a ROM reader and all I get are one
> or two identical codes, doesn't seem right. Could some one send a ROM
> dump of their EPROM. (By the way great AP64e docs on the web, someone
> (sorry forgot name) did great work there !

I'd like to know how far you got when you say it doesn't work ? maybe I can
be of more help then.
a few guesses are that you don't have the dip-switches correct, or the
Programming Voltage is not working or adjusted wrong. go to the diagram
below to work out where to adjust it. IIRC ~25.0V at the top of the wiper of
the Potentiometer. this info is not in the manual. yet... (:

anyway the Manual:
http://home.iprimus.com.au/figjams/apple2/AP-64e.PDF

Wayne Stewart also has another version of this book on his "organised" site.
:)

the Circuit:
http://home.iprimus.com.au/figjams/apple2/AP64Ecct.PDF

haven't done a complete EPROM dump yet, it's a bit of a catch 22 to get an
EPROM image when you only have one working Programmer, but I have captured
enough of it from memory to make another EPROM and then put that back in to
read the original completely. ie so far I only have captured the 256 byte
SLOT space and the 2K Expansion ROM out of a 8K EPROM (2732). the is 7x256
bytes missing.

if you need help or any measurements done to compare to your card, let me
know and I will see what I can do. (email me at figjams AT primus DOT com
DOT au)
it is very important to get the dip switches right. I found that out after I
first got my card and misunderstood the instructions, and actually had the
dip switches opposite to what they should have been. after now drawing out
the circuit I can see there is potential to damage chips if the dip-switches
are in the wrong positions. this is why I added a note into the book where
the dip switch settings are on page 3. I would also recommend switching off
your Apple before changing dip-switches to prevent damage to the card/or
Apple.

> 2)MPC AP-EP This one doesn't have a EPROM so I'm assuming it has to have
> 3) YKH-128 This is the nicest one Will allow me to burn 128k chips. (for

sorry can't help with these two.

> So there I am 3 cards - No way to read defective EPROM with the other
> two. and no way to use the other 2 to make REV C scsi chips.  Help!

There is some work being done between Laine Haughton & myself on a mod for
the AP64e to do 27128's and 27256's. not sure when I will get time to
continue on that yet, but I did post a question a while back, asking if
anyone can tell me what component is fitted at location D2. On the drawing I
put ZD2, which may be wrong. On my card it is simply a signal diode 1N4148
(to clip any negative going pulse from Vpp), but there was a suggestion that
it may be a Zener on some cards. if you can tell me what your card has at D2
(near the bottom of the DIP switches) then that will help me. If you don't
know a close up picture or just the codes on the diode may be enough.

Mark
down under (: