21MX proms (per request

[Glen Slick]

On Tue, Sep 8, 2015 at 1:19 PM, Sean Caron <scaron at umich.edu> wrote:
> The median listing price for them on eBay for a 29B with pack seems to be
> around $3-400 which IMO is a little steep for a 30+ year old PROM
> programmer. Hopefully your best offer successfully accepted was much lower!
> I think the part cost on the PROMs pales in comparison.

You can currently buy a BP Microsystems CP-1128 for $38.50 shipped on eBay:
http://www.ebay.com/itm/181853494660

For the HP 21MX PROMs being discussed it supports at least the following:

256x4 tri-state output
AM27S21
DM74S287
82S129 / 82S129A

512x8 tri-state output
AM27S31
DM74S474
82S141

1024x8 tri-state output
AM27S181
82S181 / 82S181A / 82S181B / 82S181C