RT PC Memory Expansion

2MB Memory Expansion
4MB Fast Memory Expansion
8MB Fast Memory Expansion


2MB Memory Expansion P/N 6298286, HMS says P/N 629928, no FRU

Note the "2MB ECC Memory" in the upper left corner.

Lots of 41256-15 chips, 40 per side. There are also logic chips within the ranges 1-50 and 73-120, so don't get excited.

Note the lack of any jumpers. Fast Memory cards have a jumper to set speed.


4MB Fast Memory Expansion P/N 61X7005

J3 HMS only shows this jumper in the "Fast" position. No explanation.

M1-40,41-80 65X5506(ESD); Looks to be set up for interleaved memory.

The center chips are all glue logic.

This card is only used with the RT PC Advanced Processor Board. (Oh?)

The HMS says to identify this card, look for the "4MB Enhanced ECC Memory" printed on the option.

When using 'Enhanced ECC memory' boards, make sure that the jumper on the memory cards is in the 'fast' position. The undocumented jumper allows the newer cards to work with the older processors by moving it to the 'slow' position.


8MB Fast Memory Expansion P/N 60X5777, HMS says P/N 61X7009, no FRU

M1-40,41-80 6470780(ESD) 1Mbit DRAM? Used on the 1MB Model 80 memory card.

J3 HMS only shows this jumper in the "Fast" position. No explanation.

Same layout as the 4MB Fast Memory Expansion, but at least on this one, there is a sticker saying "8MB Enhanced ECC Memory" top center.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

Ardent Tool of Capitalism is maintained by Tomáš Slavotínek.
Last update: 20 Jan 2024 - Changelog | About | Legal & Contact