Response from Jonathan: Phillip,

There are a couple of places where your MK4 cabinet might be having some issues. These types of problems are typically located somewhere on the monitor chassis. We would start off by checking the connection between your JAMMA harness (where your MK4 board plugs in) and your monitor chassis. Make sure that these wires are not frayed and that the connector is making a good connection with your monitor chassis. You might need to touch up the solder on the back of these pins on the monitor chassis as they can become loose and subsequently cause a bad connection.

Another area you might want to check out is the neck board of your monitor chassis. There are color transistors and resistors on this board that drive the red, green and blue colors on your monitor. We recommend checking out our post on Checking A Monitor Tube for more information about these transistors.

Hope that helps. Thank you for your question and good luck with your repair.