item - vintage NOS 8pc lot of 256x4 28pin 80ns ZIP dual port VRAM-DRAM (Fast Page Mode) memory for some legacy video cards and computers. Each chip is 1Mb (1 megabit) thus 8 chips equal 1 megabyte (non-parity).

NOTE: (from online)...

DRAM organized as 262144 words of 4 bits each interfaced to a serial-data register or serial-access memory (SAM) organized as 512 words of 4 bits each. Supports 3 types of operation: (1) random access to and from DRAM (2) serial access to and from the serial register (3) bi-directional transfer of data between any DRAM row and the serial register. Can be accessed simultaneously and asynchronously from the DRAM and SAM ports, except during transfer operations.

In past, the main use of this chip was as VRAM memory on many 3rd party video cards that often came with 1MB soldered on and 1-3MB of open sockets that allowed user upgrade (some boards were thru pin and req'd soldering). Offhand, I'd guess most video cards that used these were in the Mac camp, the likes of Radius, RasterOps and SuperMac.

cond - xlnt functional & cosmetic cond - NOS in original tubes

      1 MB non-parity lot specs :

  • 8pc 256x4 bit ZIP chips
  • 5v dual port VRAM-FPM DRAM
  • 28 pin, tin leads
  • 80ns access time
  • Micron MT42C4256Z-8 - USA

    will post 9pc parity lots per request

returns - NO returns unless defective - 30 day warranty

shipping USA - USPS 1st Class - no charge local pickup - combined shipping whenever possible (will refund excess on multi BIN items) - usually ship within 2 days of payment - will ship in original tubes, or cut down tubes pending order quantity and destination.

shipping International - USPS Int'l 1st Class to Europe, Canada, Australia & Japan, please email for other locations. Label will show actual item cost (not gift) and buyers are responsible for any import tax. Major USPS rate increase early 2016 - no more oz rates, now single rate up to 1/2 lb. (8 oz) then rates per lb. Will combine shipping whenever possible and subsidize the 1st 1/2 lb. into a flat rate of $12 for all countries (wait for invoice if multiple items).

payment - PayPal only - please remit within 3 days

comms - Please keep pre & post sales comms within ebay messenger, will respond within 24 hrs.


Personal Profile: middle-aged tech with a flair for legacy stuff