> > On Sep 5, 2016, at 9:30 AM, Josh Dersch <dersc...@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
