Compaq Deskpro 386s/20n: More RAM

13Oct/162

Compaq Deskpro 386s/20n: More RAM

This has been a challenge. The user manual only really indicates the spare-part numbers for modules, but searching for those proved difficult. Therefore I went in for the lucky dip and purchased whatever I could find on eBay.

First was a cheap batch of unknown SIMMs. They all turned out not to work. I then purchased 2x4mb EDO SIMMs specifically by Compaq, but they didn't work either. There's a few FPM SIMMs below that should work... maybe they've been damaged by static or are of the wrong spec. Seems like I need compaq-certified FPM and hopefully I've now ordered the right parts.

Here's what I've got, what worked and what didn't. I've used the DRAM info page at retro hardware to try and determine the module information.

Update: There's a link here at efetcher that indicates I need parity RAM.

Module details	Chip details	Status
Original 2mb SIMM (256kbit x 4) x 16 = 1mbit x 16 = 8MB x 2 = 2mbyte	HY4424 COMP#118689-001 KM44C256BJ-8 (x16) KM41C256J-8 (x8)	Works - 2mb

Compaq 2x4mb EDO SIMMs	Compaq 185173-002 - EDO - 4MB Fujitsu 814405C - 60 9269 F98 (8 chips)	Does not work

Could be SMART CQ SM5321000W-7 1mbit x 16 = 2mbyte x 2 chips = 4MB	HY5118160 JC - 70 9545A KOREA (2 chips)	Does not work

4MB DRAM	Singapore TM248GBK32U-60 9706 TM5418169DX (4 chips)	Does not work

4M bit dynamic RAM organized 1,048,576 x 4-bit 4mbit x 8 chips = 8mbit (1MB) x 4 chips = 4MB Maybe EDO?	HY514400A J - 70 9512B KOREA (8 chips)	Does not work

IC 4M X 4 FAST PAGE DRAM Another 4MB FPM?	VG2617400EJ ABORL1 - 6 (8 chips)	Does not work

4M bit dynamic RAM organized 1,048,576 x 4-bit Officially EDO. 16 chips = 8mb.	SEIWA - Made in Japan HY514404A LJ - 60 9461C KOREA (16 chips)	Does not work

4M bit dynamic RAM organized 1,048,576 x 4-bit Officially EDO. 16 chips = 8mb.	4mb 72-pinn PARITY SIMMs	WORKS! - 8mb