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VectorGlow
10th May 2009, 09:12 PM
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)