Re: Question about Midway Trog boardset

The resistors look fine to me. However it does report a bad eprom.
Sometimes it passes the self-test and other times it fails. Perhaps
that's the reason because the game still plays fine.

Matt

On 1/28/2013 5:47 PM, David Shoemaker wrote:
> Real common resistor ladder. I would check to make sure that all the
> output bits are getting signaled.
>
> Could have a bad color prom it bad resistors in the ladders.
>
> Also verify that ground us coming across correctly. If the ground is
> bad the monitor ground can be floating above PCB ground effectively
> reducing the color intensity
> ------------------------------------------------------------------------
> From: Matthew Rossiter <mailto:matt@rossiters.com>
> Sent: ‎1/‎28/‎2013 5:04 PM
> To: rasterlist@vectorlist.org <mailto:rasterlist@vectorlist.org>
> Subject: RASTER: Question about Midway Trog boardset
>
> Hello Everybody,
>
> I have a quick question about a Midway Trog Boardset
> <http://www.arcade-museum.com/game_detail.php?game_id=10201>.
>
> It seems to be working fine but the screen is very dim. The logical
> response would be that it's the monitor. I'm using an Amiga 1084S
> Video Monitor and it's perfectly fine (bright and colorful) for any
> other game, so it has to be the boardset. I also tried sending the
> video to my other flat screen computer monitor using an RGB/VGA
> converter, but the signal drops out alot. So maybe it's sending out
> weak signals. The board voltages look pretty good. Pretty much +5v
> and +12v.
>
> The Schematic for the Video Output sections is here
> <http://www.arcade-museum.com/manuals-videogames/T/trog.pdf> on PDF
> page 55. I'm not much of an expert on Jamma boards. Any suggestions?
>
> Matt
>
>

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Received on Tue Jan 29 15:19:36 2013