The Space Encounters Test Rom makes it easier to diagnose and repair your Space Encounters game. There are two rom images included in the ZIP file.
setest_716.bin - 2k image for a 2716, install in location "H"
setest_732.bin - 4k image for a 2732, install in location "H"
Depending on the strapping of your Space Encounters PCB, use either the 2716 ROM or the 2732 ROM. The 2732 ROM is a doubled image of the 2716. Remove the ROM in location "H" and replace it with the Test ROM. None of the other Space Encounters ROMS need to be removed.
Once the Test ROM is installed on the game board, the program goes through a test of the pcb's ram. If a bad ram is found, the program displays a letter or number corresponding to the location of the bad ram. See the figure below to identify the corresponding bad ram.
Only the first bad ram found is displayed. Remove the bad ram, install a socket and a new ram chip and re-run the test to find any other bad rams. If all RAM are good, a screen will be displayed stating "ALL RAMS OK".
Next the test rom displays the current status for the game's inputs.
Port 0 bits 0-5 are used for the input from the horizontal angle encoder.
Port 0 bit 6 is the input from the trigger.
Port 0 bit 7 is the coin switch.
Port 1 bits 0-5 are used for the input from the vertical angle encoder.
Port 2 is the current dip switch settings.
At the bottom of the screen is a section for output tests listing the eight sounds made by the sound pcb. To the right are three visual effects, testing the strobe unit (STROBE), the red light bulb (LAMP) and the brite circuit (BRITE) which fades the CRT up to an all white screen.
Locking on an Output
The program cycles through each of these outputs, displaying a ">" symbol next to the output under current test. If you want to stop the test cycling and focus on one output, press the trigger during the test you want to "lock." The program changes the symbol to a "*" and will infinitely loop on that one test. To resume the other tests, power cycle the machine.
While this test rom is done for now, I can always think of new features. Here are a few I'm considering for future updates:
1. Test and display ALL bad rams. It would be nice to know how many rams you are going to need to replace from the outset.
2. Tests for the trench circuit.
3. ROM tests. These are currently available in the game program itself, but would be nice to have a check here as well.
Download the Test ROM
The Space Encounters Test ROM is provided free of charge to assist in (and encourage!) the diagnosis and repair of Space Encounters games and is Copyright 2008 by Outerworld Media. Please distrbute this rom only though this page.
Click here to download the current version v1.0.
Thanks to Paul Sommers for dumping the original Space Invaders Test Rom, on which this rom is based.