View Full Version : IBM 5170 Piggyback Ram Substitution

March 1st, 2016, 06:05 PM
I have a buddy who isn't local to me who is having trouble getting his 5170 up. It's throwing parity errors and his machine is early enough that it uses those ZA1250NL piggyback DIP-16 chips. I've yet to find any indication on how to substitute them. He has heard word that the more available M37S64A's might work and you should be able to mix the two types but has no confirmation on this.

March 1st, 2016, 09:49 PM
Replacements are shown at [here (http://www.minuszerodegrees.net/memory/41128.htm)], where the '*' column contains a "Yes".

March 1st, 2016, 09:50 PM
There's at least one Canadian seller offering them NOS (http://www.ebay.com/itm/Texas-Instruments-ZA1250NL-TI-Piggyback-RAM-New-Rare-IC-Chip-Semiconductor-/201370205138)

But there are substitutions. See here (http://minuszerodegrees.net/memory/41128.htm) (I see that someone beat me on this one by a minute :) )

March 2nd, 2016, 07:45 AM
That chat was precisely what I was looking for. I wonder why Google didn't catch it.
Anyways, thanks both you.