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 '_at_' 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.
http://www.parse.com/~ddunfield/museum/index.html
Received on Tue Jul 20 2004 - 19:16:12 BST