Re: Asteroids PCB repair - fixed one problem, now have another

Hey Art I'm sure your just as good as me on repairs, but I'll give you my 2
cents if you want it :)

I would lift pins 9 and 5 of the ls259 and then you can drive those enables
low and see if you get the saucerfire sound and the shipfire sound. If so
then you got a bad 259 else may the force be with you ;)

Fred

  ----- Original Message -----
  From: Artfromnys@aol.com
  To: vectorlist@vectorlist.org
  Sent: Thursday, December 04, 2003 8:06 PM
  Subject: VECTOR: Asteroids PCB repair - fixed one problem, now have another

  Put an Asteroids on the bench today, no video, played blind. Threw it in selftest, RAM OK, some ROM errors. Changed ROM at F2 - self test now perfect. Placed in game mode - no picture, spotkiller on on the monitor. Changed ROM at D/E 2 - video is fine.
  I didnt bother trying to figure this out, other than swapping the ROMs back and forth a few times and getting the same results. I guess that ROM selftest isnt perfect.
   
  Now - ssecond problem - ship fire sound same as saucer fire sound. All other sounds ok. I am suspecting bad LS259 latch at M10 sending out the saucerfire signal when activated for either ship or saucer fire - how far off am I? Didnt have time to throw my chip checker on the chip today.

  --

  Art

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Received on Thu Dec 4 23:27:46 2003