Re: Help with Dead Gravitar Board

take a look at the chips between the ram/rom and the processor.....74245's and maybe the rom select ic
  ----- Original Message -----
  From: Malcolm Mackenzie
  To: vectorlist@vectorlist.org
  Sent: Saturday, July 22, 2006 5:31 AM
  Subject: VECTOR: Help with Dead Gravitar Board

  Hello all. New subscriber here. Finally got my first vector game (Space Duel) and have really been enjoying it. Inspired me to get some more. Thought I'd introduce myself and pose my first questions.

  I recently bought an "untested" Gravitar board and of course it was dead. I have been testing it in my Space Duel. Initial, and current symptoms are:

  No game sounds (game doesn't play blind)
  No video, Spotkiller on
  Both Game start and Game select LEDs on (not flashing)
  Self test sometimes results in 2 tones, sometimes not
  Sometimes, for unexplained reasons, the coin solenoids will chatter when the game is powered up
  Tried grounding the watchdog to see if the self test would operate with no effect

  So far I have:

  Reseated the ROMs
  Tested the custom chip (it works)
  Replaced the 6116 RAM
  Replaced the Pokeys
  Replaced the processor

  All of this has had no effect on the performance of the board. I was thinking I'd check the ROMs next. The board has a repair in the XY output section where two of the four 1495 chips have been socketed. I tested the repairs and they seem to be ok. I don't have any 1495 chips to test to see if these are the problem. Since the board seems to be resetting constantly, I'm figuring this isn't the main problem.

  This is the first Atari board I've ever worked on. Anyone have any specific suggestions for me? Where should I start with the logic probe? Thanks for any and all help. -Malcolm

------------------------------------------------------------------------------

  No virus found in this incoming message.
  Checked by AVG Free Edition.
  Version: 7.1.394 / Virus Database: 268.10.3/394 - Release Date: 7/20/2006

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Sat Jul 22 02:42:36 2006