Re: G08 width and centering problem

kstillinger@sc.rr.com wrote:
> Hey-
>
> I've been looking at a G08 here for a few weeks now on and off. Everything else finally fine, the width is not sufficient to fill the screen and the centering is off.
> I've tried a bunch of different stuff and replaced parts for other issues along the way.
> The 'left' side of the image won't reach all the way over. Messing with the horizontal width and centering pots can only get it about halfway from center to the side. The problem persists with different input protection boards and output transistor assemblies. I replaced Q704 MPSU60 with a recommended equivalent (MPSW92) and first thought the problem was due to a mismatch with the old Q703 (MPSU10) so I subbed the recommended MPSW42. No change.
> Both X and Y signals look nicely centered around 0V, so that's not where the offset is coming from. Twisting the Horz centering pot to each side seems to affect the right side more than the left. I can actually get the right side shifted off to where it is clipped. Even the Hwidth pot seems to affect the right much more than the left.
>
> I thought the horizontal side R735 3 ohm 20W measured too low around .8 ohms and I thought- that could do it. Shoot no.
>
> I figure I might try to swap the X and Y paddle boards and see if the problem follows the board.
> This is really bugging me. I can't see where the problem is being introduced.
>
> Any ideas are appreciated.
> Kerry
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>
Check for connectors not doing their job...any introduced resistance on
the paddle boards can lead to problems. I would put a bit of Dow corning
#4 Electrical Grease on ALL the pin connects to reduce contact
resistance and also reduce wear on the contacts when inserted...

We are trying to do this on all connectors these days.

John :-#)#

-- 
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
                 www.flippers.com 
"Old pinballers never die, they just flip out"
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