7 Sep
2016
7 Sep
'16
4:18 p.m.
On Wed, Sep 7, 2016 at 3:43 PM, CuriousMarc <curiousmarc3 at gmail.com> wrote:
Yep, the NEC uPD416D's are what we have in the Alto we recently restored.
And yeah, it takes awhile, but it's worth the effort :).
Have fun!
- Josh
> On Sep 5,
2016, at 9:30 AM, Josh Dersch <derschjo at gmail.com> wrote:
>
> At the LCM, I used an Apple II to test out the Alto's memory -- the
> Alto II XM uses 4116 RAM chips. I swapped in a row at a time and wrote
a
> little BASIC program to test for obvious
errors. This was
> time-consuming, but eliminated the obviously bad chips, which helped
immensely.
Oh, that's so simple and clever! Are these 16k chips? I don't have an
Apple II,
but I wonder if I could use the same trick and
plug them in my HP 85
for which I just managed to burn the service ROM, which has a memory
test built in.
Josh,
I checked, and the mysterious HP 1818-1396 or 1818-0341 RAM chips used in
the HP-85 appear to be NEC uPD416-2 or MOSTEK 16k chips. They appear to be
pin for pin, voltage and speed compatible with the MOSTEK 4116-3 used in
the
Alto. So it looks like I could check the Alto Xerox II-XM RAM chips on my
HP-85.
8 at a time, that might take a while :-). Thanks for the tip, I'd never
have
thought about it!
Marc