DEC Laboratory Module Building Blocks

DEC Laboratory modules were developed in the early 1960s and are a predecessor to DEC's System Modules and Flipchips. These were DEC's first revenue generating product.

We have two chassis full of DEC Laboratory Modules. The Digital Logic Handbook has limited documentation on these modules. The manual says that the later System Modules use the same circuit design, but have the next generation of packaging. We have schematics for some of the System Modules that we can use for reverse engineering the power connections and to see if any of the Laboratory Modules work. We plan to wire up a binary counter with the 3401 Clock Module and 8x of the 3201 Flip-Flops. The Flip-Flops have indicator lights on the front so you can see the binary counter count.

The chassis has a backplane in the back that distributes +10VDC, -3VDC, and -15VDC to the Laboratory Modules. The back of the Laboratory Module power backplane showing the power distribution buses is shown above. The connector at the left is the power input, and the connector to the right is the power output to the next chassis.

The input power connector on the back of the Laboratory Module chassis. There are two separate +10V buses.

The power connections on the back of the Laboratory Modules.

The above images show the 3401 Variable Clock. The rotary switch selects one of 5x capacitors to select a frequency range, and the potentiometer allows for fine adjustment of the frequency. This module is similar to a 1404 System Module.

We connected the 3401 Variable Clock to a -15VDC source and it actually works. Not bad for 60 year old parts. The Frequency is adjustable in 5x ranges. The low frequency is about 2.1 Hz, and the high frequency is 610 kHz.