Drastik version 1.0 is compatible with the TRS-80 Model 1. It is eletrically compatible with the System 80/Video Genie but there are mechanical issues that prevent it from being used.
To install, follow the steps below
Step 1
Collect the required parts:
- An assembled 16k or 48k Drastik board
- Two flying leads each with a single pin DuPont socket
- One eight pin DIP switch
- One DIP plug with pre-soldered links
- Three long cable ties, or six short ones
- A high density foam pad (may already be attached to bottom of the board)
Step 2
Remove all power and connectors from the Model 1 keyboard unit and turn it over so the bottom is facing up.
Step 3
Remove the eight screws to reveal the main motherboard.
It is possible to install the Drastik without removing the motherboard and keyboard from the case, but I recommend laying both boards flat on your desk.
Step 4
Locate the eight 4116 RAM chips and carefully remove them from their sockets using a small flat-blade screw driver or specialised IC removal tool. Store these ICs safely for later use if required.
Step 5
Remove the two jumper banks labelled Z3 and Z71. Store these jumpers safely for later use if required.
Step 6
Insert the eight pin DIP switch into Z3 and configure as shown below.
Step 7
Insert the DIP plug into Z71 and as shown below.
Step 8
Locate Z38 (74LS367) as shown below.
Step 9
Solder the flying lead labelled A14 to pin 9 of Z38, and the flying lead labelled A15 to pin 11 of Z38
Step 10
Slide a cable tie underneath three of the RAM sockets as shown below
Step 11
Insert the Drastik board into the eight RAM sockets. The 16 pin plug inserts fully into the right-most RAM socket. The row of seven pins inserts into pin 2 of the seven RAM sockets to the left.
Ensure the pins on the bottom of the Drastik go into pin 2 of the RAM sockets and not pin 1
Also ensure the foam pad on the bottom of the board does not interfere with the pins.
Step 13
If using the long cable ties, zip them closed to seat the board firmly against the foam pad
If using the short cable ties, attach a second tie to each pad and then zip closed
Step 14
Attach the flying leads for A14 and A15 to the connector on the left hand side of Drastik board
Step 15
If you have the motherboard and keyboard laid out, it is possible to insert the power and video connectors, and power up the machine to test.
Depending on which board you have selected, you will be able to print the memory size as follows:
Step 16
Reassemble the motherboard and keyboard into the case, and you’re done!