One of the most useful resources in the arcade community is the excellent Arcade Repair Tips video and podcast series. In it they help explain everything from the basics to the more complicated repairs that you’ll run into when fixing a game. Their latest post covers monitor convergence and is a must read for anyone who wants to do a tube swap.
In order to display the image on a monitor properly, the chassis has to be tuned into monitor that it is attached to. This is primarily done through a big copper coil called the yoke, but there are also things like convergence rings and convergence strips that can impact the image that you get. A monitor that is out of convergence will typically display double images and the colors will look like the are tie dye and will pool in certain areas.
In their blog post, the Arcade Repair Tips crew dives into an in depth discussion on the differences between static and dynamic convergence.
“The first thing to note is that there are actually TWO types of convergence you need to adjust: static and dynamic. The first is static and is the easiest. This is where you use the convergence “rings” on the yoke. Using the game’s test screen, you have it display a grid pattern. Then, using two of the rings, you adjust the red and blue vertical lines until they overlap one another. Then you adjust the red and blue horizontal lines until they overlap. Once this is done, you adjust the rings in order to get the red and blue to overlap the green lines. The manual describes this very well and also has illustrations. This process is actually much simpler than most people think but it can be a little intimidating at first. Once done, you can use a marker to mark all of the rings for reference.
Next is the tricky part: dynamic convergence. Whereas “static” convergence covers mostly the inner area of the monitor/screen image, dynamic convergence covers the outer area, particular the edges. For example, if you had white text running across the entire monitor, you might notice that while the letters at the center of the screen look fine, the letters on the far left and right looked “ghosted” with shades of red, blue and green above and below. This is dynamic convergence that needs adjusting.”
Even the most experienced arcade techs can have trouble with convergence, so if you can’t get the hang of it don’t be too discouraged. We’ve got a special tool that we use to help align the colors (pictured above), but even with the extra help, it’s not always easy to line things up. Good luck with your own convergence issues and thanks to Arcade Repair Tips for helping to better explain what it’s all about.