Centipede Monitor Problems - Electrohome G07-CBO

[gamestar]

Hello everyone, first let me say I love this site. Learned alot already. You all rock!

I have a centipede game that has some monitor issues. We had the old monitor replaced with a pacman monitor (Electrohome G07-CBO) and I've done a "cap-kit" on it. All went well but still having some display issues. As you can see from the fuzzy pics (sorry), picture 1 shows a horizontal scrolling problem. I've adjusted the sync and freq but can't lock it down. Picture 2 shows a double display of some characters at the bottom of the screen, they tend to flicker and move horizontally in sync with the correct characters above.

I wonder if there's something i've missed in adjusting the monitor or do I need to degause it? Just not sure. Thanks for any help.

[Ken Layton]

What make/model was the old monitor? Centipede's wiring may have two differently wired monitor connectors provided. Some games had an Atari "Disco", Matsushita 202, or Electrohome G07 installed. You used the conector set that matched your particular monitor model. Sounds like you may have the wrong connectors plugged in. Be sure to look thru your Centipede wiring diagram package for the correct harnesses.

[gamestar]

Hmmm, not sure what the old monitor was. I had an arcade repair man come out and replace the old monitor. Wish I would've done a cap kit on the old monitor first, maybe that would've worked. 

[gamestar]

Any suggestions... anyone?   

Does anyone know if this monitor is + or - sync?

[Ken Layton]

I believe the Centipede game board sends out positive sync to the monitor.

[rchadd]

i had a similar sync issue with a Hantarex MTC9000 monitor (it was a lot worse)

http://forum.arcadecontrols.com/index.php?topic=41214.0


resolution was simply matter of changing the polarity of the sync (to positive sync) - luckilly the monitor had a switch on the chassis to allow this.

if you dont have a swtich on the monitor i think it is possible to make a circuit to change negative sync into positive sync

then again if monitor is already set to positive sync its probably a different issue...

[Ken Layton]

On some monitors you use an alternate set of connector pins depending on the sync polarity you're going to send it. On Electrohome G07, the 3 pin connector is for negative sync while the 6 pin connector is for positive sync.

[gamestar]

Thanks, I read your thread and i'll try it next week as I am going away for the weekend. Hopefully it works.