IBM SLT Modules  
Written by Accutron on 2007-10-03  

Devices included in this entry:

IBM 6332YB SLT module
IBM 7448YB SLT module
IBM 7480YB SLT module
IBM 7528YB SLT module
IBM 8267DO SLT module
IBM 8268YE SLT module
IBM 8279DO SLT module
IBM 8926YH SLT module (pictured in thumbnail)
IBM 831290 SLT module

First developed for the System/360 in 1964, IBM's proprietary Solid Logic Technology (SLT) hybrid integrated circuits were used to build both their mainframes and smaller computers like the IBM 5100. Earlier SLT ICs are built from glass-encapsulated transistors and diodes mounted on a ceramic substrate, while later devices feature a monolithic construction. SLT circuit cards have an unusual multi-layer design with a grid of solder pads covering the entire board. IBM SLT modules are believed to be the first implementation of BGA interconnection, now a prevailing standard in the electronics industry.

In the not-so-distant past, SLT modules would occasionally flood the surplus collectors' market, usually with no accompanying pedigree. If you can identify any of the cards pictured here, please contact us.

Four small IBM SLT modules: 6332YB, 7448YB, 7480YB and 7528YB.

Two small SLT modules in a single pull-out frame: 8267DO and 8279DO.

8279DO module, underside construction. note the unusual trace style.

IBM 8268YE SLT module.

8268YE module, underside construction.

IBM 8926YH SLT module.

IBM 831290 SLT module.

IBM SLT monolithic circuit, internal construction.

This article is part of the [Logic & Memory Circuits] exhibit.

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