[Premium-Rx] Jim Garland's MECL Chips

[Geoff Fors]

Jim,

All those Motorola MECL II chips are in the 1968 Motorola "Integrated Circuit Data Book."
I can make you copies of the data pages on each of them if you wish, but contact me off-list about that.  They are clocks and gates and flip-flops as you surmised.  I don't have the spare time to scan and process them as digital files, but I can photocopy them.

These chips were truly state of the art in the late 1960's but vanished when TTL became the norm.  It's amazing how hard it is to find data on them these days!

As I recall these early MC- prefixed devices are RTL and MECL use a 3 volt VCC so you can't just swap some common TTL chip and expect it to work.  

Normally, troubleshooting something like this would involve a handful of good chips, a bugtrap, maybe a scope and a Huntron Tracker, and a logic probe, but you don't have the luxury of known good chips and I don't think the Bugtraps work on MECL or RTL.  Oh yes, by the way, don't forget to check for shorted electrolytics and tantalum match-head style capacitors.

This topic points out some of the difficulties intelligence agencies faced when trying to reverse engineer pieces of equipment captured from "enemy " nations.   Today, everything is full of Motorola, Intel or other western name brand chips!

Geoff Fors  
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