 |
|
The best way to diagnose a ROM board is by removing all ROM chips and getting the minimum amount of ROMs needed (listed below) to boot up the game to an error screen. After you have an error code on the screen add one ROM chip at a time. In order to see an error message on the screen you need at very least a working CPU board and a working ROM board with the following good ROM chips installed. The first thing that needs to be done is replace the 40 pin ribbon cable, see this page for details: Replacing your ribbon cable
For Defender game:
| Rom # | If missing or bad |
| Rom #3 (needed for selftest) | blue or purple jail bars and all 4 LEDs on |
| Rom #7 | rug pattern repeats itself with #1&3 LED on |
| Rom #8 | after 2nd rug sweep you'll see a blue screen then repeats itself |
| Rom #10 | same as ROM #7 symptom |
| Rom #11 | same as ROM #8 symptom |
(above picture is from Bob Roberts website)
**Note: ROM #5 is not used**
For Stargate game:
| Rom # | If missing or bad |
| Rom #2 | white screen with correct error code on the ROM board |
| Rom #8 | rug test and error code on LED then repeats itself |
| Rom #9 | same as ROM #8 symptom |
| Rom #12 (needed for selftest) | jail bars flashing then very slow backwards semi looking rug test |
All Stargate ROM chips are 2532
For Robotron or Joust games:
| Rom # | If missing or bad |
| Rom #6 | rug pattern repeats itself |
| Rom #7 | rug pattern repeats itself |
| Rom #10 | rug pattern repeats itself |
| Rom #11 | after 2nd rug sweep you'll see a blank screen |
| Rom #12 (needed for selftest) | red and white jail bars |
All Robotron and Joust ROM chips are 2732
For Sinistar game:
| Rom # | If missing or bad |
| Rom #6 | rug pattern repeats itself |
| Rom #7 | rug pattern repeats itself |
| Rom #10 | rug pattern repeats itself |
| Rom #11 (needed for selftest) | after 2nd rug sweep you'll see a blank screen |
| Rom #12 | red and white jail bars |
All Sinistar ROM chips are 2732