TECH: Sanyo Monitor is very dark got me stumped (D kong).

[Bert Ankrom]

This Sanyo monitor has me stumped so I thought I would ask around.
Slightly long...
I just finished converting a Vs system back into a D Kong and all went
well with that... but here's the problem the screen is very dark...
innitially on power up the only thing that can be seen is the ladders,
then after warming up for about 10 minutes the image can finally be
made out, and is marginally playable. Then after the game has been on
for about 20 to 30 minutes the girders on the right side shart to
"smear" toward the top of the screen (probably unrelated). I installed
a cap kit from Bob Roberts and I replaced all potentiometers on the
monitor Red, Green and Blue Bias.and Red and Blue Drive, and the
brightness pot. I also looked and checked for broken traces and cold
solder joints when I capped it. I found an answer in the archives
about replacing the large (the biggest one on the monitor board)
COULD? fix this issue but I have not been able to confirm, does anyone
know what this cap is for?

One other thing that struck me as strange... I was under the
impression that Donkey Kong required an inverter board which my
monitor has. The strange part is that there are 2 places plug in the
cable that goes to the monitor main board, Non-Inverted out and
Inverted out. As it is now, when Inverted out is used the colors show
up on the screen as a negative image. But when I use Non-Inverted out,
or bypass the inverter board entirely, the colors show up on the
screen as normal (except for the darkness issue) does this seem
backwards to you as it does to me?

I did make the molex edge connector and I used the pin outs from the D
kong manual, does it sound as if I misread the pin outs and mixed up
the RGB and the sync? But, I've checked them a thousand times??? help?

Thanks for your help.

Bert's Basement Arcade (under construction)
http://www.emcity.net/sites/ankrom/index.HTML

[Geoff Gunn]

Sanyo monitor are inverted by default, and DK boards output a inverted
signal, thats why when you bypas the inverter, it looks normal.

http://home.austarnet.com.au/vax/
Cheers, Geoff
"Bert Ankrom" <bean...@tbrlaw.com> wrote in message
news:86f55adc.0207...@posting.google.com...
: This Sanyo monitor has me stumped so I thought I would ask around.

[Ken Layton]

The Nintendo monitor needs an inverter board when the monitor is used
with modern conversion kit games. For using the monitor with a Donkey
Kong board you want to use the "Non-Inverted" connector. As for the
darkness issue, if you have already installed a cap kit then try
adjusting the "sub-bright" control on the main monitor board and if
that doesn't help then try the "screen" control on the flyback. Then
if after all this it's still too dark then you may have to have the
picture tube 'rejuvenated' at a tv repair shop.

[Bert Ankrom]

Thanks for the advice. I tried adjusting every single pot on the board
including the "sub bright" and the brightness pot,the scree pot on the
flyback the drive and bias pots... I think maybe you're right... maybe
the tube is just tired, but it seemed to work ok when I had excite
bike in that cab, but that's a non-inverted game (i.e shows white
instead of black for a back ground).

KLayt...@aol.com (Ken Layton) wrote in message news:<c3d3bcef.02072...@posting.google.com>...