Repairing arcade monitors relies heavily on your ability to identify where the problem resides. Being able to tell where on a chassis the problem originates from will greatly increase your chances for a successful repair. In this post, we once again visit with our resident monitor repair guy Michael to talk about how to identify and repair some common monitor issues.
More Troubleshooting Monitors With Michael (Part One)
More Troubleshooting Monitors With Michael (Part Two)
Most of the questions we received through the website are related to problems with arcade monitors. Since the topic of monitors is so prevalent, we thought we would once again get together with Michael to discuss some more monitor troubleshooting techniques.
In the picture above we have a horizontally mounted monitor that has what appears to be horizontal lines located in the top half of the screen. It is important to note what direction the lines are running as this will help us determine what section of the chassis we need to focus on. Even though you might think that this problem is located in the horizontal section of the chassis, it is actually related to the vertical section.
Side Note: There is a common misconception that horizontally mounted and vertically mounted monitors are different, however, they are actually the same monitor. The location of the mounting rails and the way the picture is displayed are the only differences between them. The anode (located underneath the suction cup) will always indicated the top of the monitor.
When you have these type of lines running along your screen, these are typically caused by a bad capacitor in the respective section of your chassis. There are many reasons why capacitors go bad. For instance, many electronics manufacturers use cheap capacitors to cut production costs. Also, dust can act like a big blanket on top of your board heating up components and causing them to fail. This is one reason why making sure your game is sufficiently cooled is so important. Please see our post on Installing A Fan In An Arcade Cabinet for more information on cooling.
Lets say we didn’t know that this problem was related to a capacitor, we could always start by identifying what is working with our monitor. Since we are getting a picture, we know that our flyback, anode and tube are probably good and that we are getting power to the monitor. Our colors look pretty accurate so the connections from the PCB and the neck board to the chassis are probably good as well as the neck board itself. This pretty much leaves us with just the chassis. This process-of-elimination technique works very well for troubleshooting the majority of parts in an arcade cabinet.
Now that we’ve identified the problem, we can now begin to track it down on our chassis. As we said before, this problem is more than likely caused by a bad capacitor in the vertical section of our monitor. Some monitors might have this section labeled on the chassis while others will not. A good way to determine the location of the vertical section is to trace down the yoke wires coming off of the tube to the chassis. A green or yellow yoke wire from the tube usually leads to the vertical section of the chassis. Conversely, a blue or red yoke wire usually leads to the horizontal section. These sections have a location number that corresponds with the parts in that section (i.e. the vertical section might be IC600 with the capacitors in the section being number C610). This will help you in determining which parts go with which section.
When we’ve located the vertical section, we can now begin to look at the parts associated with that section. On this particular monitor there were two capacitors located in this section. Using an ESR (Equivalent Series Resistance) meter we were able to determine that the 100μf (microfarad) capacitor was bad while it was in circuit. You can also use a multimeter with a capacitance tester to check your capacitors but you must take them out of circuit (i.e. out of the board) to get an accurate reading.
Something we covered in our post on Installing A Cap Kit is the importance of replacing a cap with another cap of the exact same microfarad and in the exact same polarity position. Also remember that the voltage of the new cap does not have to match the voltage of the old cap. As long as the voltage is greater than or equal to the original cap you should be fine. Another reading you should consider when replacing a capacitor is the degrees. The degrees of a capacitor indicates what frequencies the capacitor is rated for. We recommend using 105 degree capacitors as they can handle most of the frequencies used in arcade monitors and power supplies.
Once we replaced the cap on this particular monitor, our picture was as good as new…
Remember you can always install an entire cap kit, however, these kits usually do not contain a replacement cap for every cap on the monitor chassis. Cap kits are usually comprised of capacitors that have a high failure risk. As such, your cap kit might not contain the capacitor you need to solve your particular problem. If you install a cap kit and continue to have the same problem, make sure you check some of the caps that you didn’t replace.
We talked a little bit about the thin horizontal line monitor problem in our original Troubleshooting Monitors With Michael post but thought we would revisit this topic for a moment. Should you have a monitor with this problem, check the vertical IC (Integrated Circuit) chip to see if it is good and if it is getting power. You can check it with a standard multimeter. You can try refreshing the solder around the chip but if that doesn’t work we recommend just replacing the chip altogether.
Learning how to identify problems with arcade monitors and being able to locate the source can save you a lot of time and trouble. With these techniques you should be able to narrow down the scope of your repair to just the trouble spots that are causing your particular issue. Good luck in the future with all of your arcade monitor repairs and if you have any questions please feel free to post them in the comments section below.