VectorGlow Posted May 10, 2009 Share Posted May 10, 2009 Symptom: Very ?snowy? video Cure: Bad output on pin 12 of the LS273 at location 4B of the smaller top board Symptom: When powered on the copyright text appears (ie 'typed') too fast and the static attract screens are cycled through too fast, sometimes with text and or sprites missing, and sometimes with text added (see Diagnosis for more info) Diagnosis: However, when inserting a coin the 'CREDIT 00' text either doesn't appear or doesn't count up as the board is coined up - sometimes an audible sound is played to indicate a coin up, but sometimes not. Either way, the coin ups ARE recognised (as the game WILL start). Also, when coined up, the screen saying to press 1 or 2 player start does NOT appear. On pressing the coin up button then player 1 or 2 start, the game starts and plays perfectly. No problems with sound, graphics, etc. All EPROMs are fine. Cure: Replaced LS74 at 6M on centre board (chip had bad outputs) Link to comment Share on other sites More sharing options...
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