RE: Clays AVG replacement PCB question

From: Clay Cowgill <c.cowgill_at_comcast.net>
Date: Thu Jun 09 2011 - 15:40:51 EDT

"jitter" is probably an 'analog' problem somewhere. It sounds like the AVG
is working correctly to me-- the LEDs are actually telling you that the AVG
stack address is incrementing and the game is also sending the 'clear'
signal. The vector generator state machine on the board should appear to be
running.

(More typically, AVG problems will be a game that crashes after certain
graphic shape is drawn, or where the display goes 'crazy' with repeatable--
but wrong-- lines.)

Instruction sheet for the AVG replacement is here:
<http://www.multigame.com/137179.PDF> http://www.multigame.com/137179.PDF

" There are two LEDs on the board (D101 and D102). D101 lights when the
address "increment" signal is asserted inside the vector generator. D102
lights when the address "clear" signal is asserted inside the vector
generator. These may be useful to experienced users to help debug a bad
board. (In a working Star Wars board for example D101 will glow brightly and
D102 will be significantly dimmer. If one or both are out, or too dim or too
bright it will indicate a problem with that section of the AVG.)"

-Clay

________________________________

        From: owner-vectorlist@vectorlist.org
[mailto:owner-vectorlist@vectorlist.org] On Behalf Of Jeffrey Matthews
        Sent: Thursday, June 09, 2011 4:58 AM
        To: vectorlist@vectorlist.org
        Subject: VECTOR: Clays AVG replacement PCB question
       
       
        Hi;
        I have a Gravitar that has a Clay AVG replacement PCB and the
display is "jittery" and kinda jumbled.
        D102 on the AVG is bright but D101 dim, it is lit but much less
bright that D102. I feel that this is an indication of a problem but do not
have a clue as to what.
        Have any fellow collectors come across this before?
       
        I have a thread started here:
        http://forums.arcade-museum.com/showthread.php?t=187453
        With pictures.
       
        Thanks in advance
        Jeff
       
 
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Received on Thu Jun 9 15:40:56 2011

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