Drastik DRAM Replacement

Introduction

The Drastik 1 provides 16k or 48k of RAM for your TRS-80 Model 1 with a single static RAM chip on a board that fits into the vacant dynamic RAM sockets.

It is easy to install, requiring only two wires to be soldered to the motherboard. The two socketed jumper banks on the motherboard are replaced to avoid any cuts or jumps.

The Drastik board can be unplugged at any time, and the original dynamic RAM reinstalled simply by returning the jumpers to their original settings.

Buying a Drastik 1

A small number of fully assembled Drastik 1 kits for the TRS-80 Model 1 are available for sale at $USD45 each, plus postage. These boards include the two flying leads needed for installation, mounting hardware, and jumper bank replacements.

Please email craigs@postincrement.com if you would like to buy one. Please indicate if you require a board configured for 16k or 48k.

Installation

Click here for instructions on installing the Drastik 1 in your TRS-80 Model 1.

Click here for instructions on modifying the TRS-80 Model 1 Expansion Interface to work with the 48k Drastik 1.

Instructions on converting a 16k Drastik into a 48k, or reverse, will be available soon.

FAQ

Is the Drastik 1.0 compatible with the TRS-80 Model 3 and Model 4?

No.

These systems use a different physical RAM spacing and data bus interface. A new version of Drastik may be released at a later date to support these systems.

Is the Drastik 1.0 compatible with the System 80 and Video Genie?

It isn’t, but it was supposed to be!

The Drastik 1 is electrically compatible with the System 80, and allows pins to be installed at the weird spacing required.

Unfortunately, the installed board hits a mounting pillar and the motherboard cannot be reinstalled. This problem will be fixed in a future version.

Is the Drastik compatible with the TRS-80 Model 1 Expansion Interface?

A TRS-80 Model 1 with a 16k Drastik 1 is fully compatible with the Expansion interface, without or without RAM installed.

The Expansion Interface requires modification to operate with a 48k Drastik 1. This modification is required even if all RAM is removed from the EI. See here for more information

The Drastik contains 128k of RAM – does this mean I can run CP/M or use more than 48k?

No.

The Drastik uses a 128k RAM chip because it’s widely available. Adding support for more than 48k or for CP/M would require additional hardware and software.

This might be something I will do in the future.

Why develop the Drastik?

Several reasons:

  • I needed to replace the dynamic RAM in several of my personal machines, and 4116 chips are getting hard to find.
  • I had several static RAM chips already
  • The modifications for 4164 are extensive and can’t be easily reversed
  • And most importantly, I wanted to see if I could 🙂

Where did the name “Drastik” come from?

I got tired of saying “dynamic ram replacement board”, so I came up with Drastik as a shorter version of “DRAm STIcK”