Help with Apple2 clone "Orange Peel" - test-drb@ccmp.vtda.org

20 Jul 2004

At 20:42 18/07/2004 +0100, you wrote:
...
   Btw, do you
(or anyone) have the pinout for 4564 DRAM's?  I'm wondering
 if they are in backwards (as noted previously, someone "worked" on this
 unit) - 16 pins, showing +5 on pin 8 and Gnd on pin 16 - backward to 
That is the conventioanl pinout for 64K DRAMs (like the 4164). The old 
3-rail 16K ones (4116, etc) had -5V on pin 1, +12V on pin 8, +5V on pin 
9 and ground on pin 16 (this is burnt into my brain). 

I don't think your RAM is in backwards. Certainly don't turn it round yet!

-tony 
Hi Tony,

Thanks - I hadn't "turned them around" as I wanted to be sure before doing
anything
that could cause more damage than may or may-not have already occured. I did recall
that some 5v DRAM's had "weird" pinouts.

Looks like the machine is zeroing RAM (causes a screenfull of '@' on apple
display),
and then getting "lost" before it ever makes it to the disk ROM (or at least
doesn't
turn on the drive motors) - Bad RAM would have explained that nicely (bad stack)
- I'll do some more conventional debugging to see what it is accessing and see where
that takes me.

Regards,
Dave
-- 
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.
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