When troubleshooting an arcade game, you might get to a point where you start to suspect that your board has issues. Swapping in a tested, working board in JAMMA wired cabinets is an easy way to find out if it’s your current board or the cabinet that’s causing your issues. In this post, we will discuss how to swap boards in a JAMMA cabinet for testing and conversion purposes.

Swapping Boards In A JAMMA Cabinet

http://www.youtube.com/watch?v=4eSUe5FrkC8

As mentioned in the introduction, we highly recommend keeping extra JAMMA boards around for testing purposes. Some good candidates for test boards include 8 liners boards (such as cherry master) or older JAMMA games from the late 80s and early 90s. You can purchase these types of boards pretty cheap at arcade auctions or even off of eBay. It’s OK if the board that you use for testing is not 100% working. We use an old Street Fighter 2 board that has some graphical glitches but it works well enough to tell if our cabinet is working properly.

Before we begin the process of swapping out our JAMMA boards, we recommend checking the power supply to make sure it’s working properly. Keep in mind that the board expects a certain voltage to be connected to specific pins on the JAMMA harness. Board damage or malfunction can result from incorrect voltages being sent to these pins from the power supply. Please review our post on Checking And Replacing A Power Supply for more information on checking the voltages coming from your power supply.

Once we’ve checked our power supply, we can begin the process of swapping out our JAMMA boards. Begin by opening up your cabinet and locating the board that is currently connected to the harness. Slowly remove the JAMMA harness from the board. Make sure you note the location of pin 7 (known as the key) on your main harness as you remove the board. The key helps you identify how to plug the new board into your harness. Many JAMMA harnesses have a plastic placeholder in this spot which prevents you from plugging the board into your harness incorrectly. Keep in mind that plugging the board in backwards might cause damage to your board. You might notice an additional harness (known as a kick harness) inside of your cabinet. If your cabinet has a kick harness, remove it from the board after the main JAMMA harness. At this point, you can either remove the board from the cabinet or find a partition (such as a piece of cardboard) that will prevent the current board from touching the new board.

With the harness removed from the current board, we can proceed with connecting our new board. Locate the harness coming from the cabinet. Make sure that the key on your harness matches up with the key on your new JAMMA board. Place the harness on the JAMMA connector in the correct position. You should now be able to turn your cabinet on and get a picture on the monitor. Please note that you might have some problems with your control panel especially if your new board requires a kick harness. Unless the original board and the new board use the same system, you will probably need to hook up a different kick harness to your cabinet to get all of your controls working. If you are only using the new board as a test board, plugging up the main JAMMA harness should be enough to tell if your power supply and cabinet wiring are working.

Whether you’re trying to track down problems with a game or installing an entirely new board, swapping boards in a JAMMA cabinet is a valuable skill to have. Please leave any questions or suggestions you have in the comments section below.

When an individual button or joystick direction stops working properly, we tend to blame the problem on bad wiring or a faulty switch. When several buttons and/or joysticks stop responding, the problem can usually be traced back to faulty ground wiring between these parts. In this post, we will discuss how to connect (or reconnect) the ground wires from your harness or power supply to the various parts on your control panel.

Connecting Ground Wires On A Control Panel

http://www.youtube.com/watch?v=5TFo7bFhm74

In our post on Getting Familiar With The JAMMA Standard, we talk about a technique of connecting ground wires called daisy chaining. Daisy chaining is a wiring scheme that consists of jumpering a wire off of each connector so that the ground signal will carry over to the next connector. Some harnesses that you can buy will already have the ground wires daisy chained together which make it very easy to connect the ground wires to your control panel parts. For those of you who do not have this luxury, you will have to daisy chain the ground wires together yourself. This will be our main focus for the rest of the post.

Before we can begin daisy chaining our ground wires, we first have to identify the source of our initial ground wire. Most harnesses (including your standard JAMMA harnesses) have ground wires attached to them that should work for your control panel. Make sure that you look up the pinouts for your specific harness to help you locate the ground wires. DO NOT try to locate the ground wires by the wire color as these colors can vary greatly between harnesses. If you are having trouble locating a ground wire on the harness, you also have the option of connecting a wire to the ground screw or pin on your power supply. Most power supplies (like the one in our video) use the letters GND to indicate which pins or screws are a ground output. It’s a good idea to crimp a terminal on the wire you are going to use as your ground if you are using the power supply as your ground source. We prefer the U-shaped fork terminals over the O-shaped ring terminals as they are easier to remove without having to completely remove the screw from the power supply. Make sure you also invest in a good crimper (preferably ratcheting) so that the wire will not come loose from the terminal. You will need this crimper later when we’re crimping our quick disconnect terminals for our switch wires.

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In order to complete the daisy chaining process, we will need some extra wire (preferably the same color as your ground wire) and some female quick disconnect terminals. Quick disconnect terminals come in various colors which usually indicate the gauge of wire that they can hold. The two main colors that we tend to focus on are red (22-18 gauge) and blue (16-14 gauge). We recommend using the blue terminals when wiring a daisy chain as it gives you more room to put both wires in the terminal. Quick disconnect terminals also have a tab width which indicates how large the tab is that you’re trying to connect to. Most arcade game related Cherry switches come in one of two different tab widths: .187 and .250. Make sure that the tab width on the quick disconnect terminals you order matches the tab width on your Cherry switches. It is important to note that you can daisy chain wires together without these terminals by using a soldering iron, however, it makes replacing parts in the future a bit more inconvenient.

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Once you have all of the parts that we have discussed, we can begin the daisy chaining process. We like to start this process by beginning with the player one start button; however, the start position does not matter so you can start at a different position if you wish. Take the ground wire coming from your harness (or power supply) and the extra wire that we discussed earlier and strip the ends of the two wires. Place both wires side by side and twist them together. Take the twisted wires and place the stripped ends into one of your female quick disconnect terminals. Using the crimper, firmly crimp the wires so that they will not come loose from the quick disconnect terminal. With the wires crimped, connect the quick disconnect terminal to the proper Cherry switch tab. If you’re not sure which tab is the ground tab on your Cherry switch, it’s usually the one that’s off by itself on the side of the switch. With the first quick disconnect terminal attached, take the extra wire and run it to the closest button to your current position. Measure about an inch or two past this point and then cut the wire at this position. Strip both ends of the wire and then twist the wires together as we did on the first wires in our chain. Place a quick disconnect terminal on to the ends of the wires and crimp it. Now repeat this process until you get to the last button in your chain at which point you will only have one wire crimped inside this quick disconnect terminal.

We receive a lot of questions about control panel parts that all of the sudden have stopped working. Now that you knowing how to connect ground wires properly, you should be able to troubleshoot these types of control panel issues in a more effective and efficient manner. Please leave any questions or suggestions you have in the comments section below.

If you’ve played many arcade games in your time, you’ve probably noticed that not every game uses the same amount of buttons. For instance, fighting games such as Street Fighter 2 are known for their 6-button layout while some classic games such as Pac Man require no buttons at all. Due to these differing configurations, there may come a time when you need to add a button to play the game properly. In this post, we will discuss how to install a push button on your control panel.

Installing A Push Button

http://www.youtube.com/watch?v=56MeeHy2Qj4

Before we can begin this process we will need a couple of tools. First off, you will need some sort of drill to cut the hole. We recommend using a drill press if you have access to one. Using a drill press allows for a cleaner, more consistent cut that will reduce the amount of splintering (or burring in the case of a metal control panel) around the hole. If you do not have access to a drill press, a corded hand drill will work as well. You will also need a 1 1/8″ hole saw. We prefer the bi-metal type as they are good for cutting into either wood or metal surfaces. Safety goggles are also very important as pieces of the control panel can fly up at your face during the drilling process. You might also consider getting a clamp to hold the control panel steady as you cut. Of course, you can also recruit a friend to hold it firmly to provide similar stability.

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Once you have gathered your tools we can begin the process of cutting the button hole. Our first step is to determine where we want to place our new button. Our technique is to place a small dot in the center of a button that’s around the same area that we want to place the new button. From here we can measure from the top of the control panel to the dot which will help us align our new button with the already existing button. We can then identify where we are going to place the new button in relation to the current button (usually either to the right or left of it) and measure down accordingly. It’s a good idea to leave at least some distance between the two buttons as you don’t want your buttons too close together or too far apart. When you are satisfied with the location, place a small dot on the control panel. This will serve as our center point for our new button hole.

When you have found a satisfactory location for your button hole, we can proceed with cutting it out using our drill and hole saw. As we talked about earlier, it’s a good idea to secure the control panel at this point using either the clamp that we talked about or a friend to hold it down. If you are worried that the hole saw bit might not stay in place on the control panel, you can drill a small pilot hole to help guide it. With the control panel secured, place the hole saw in your drill and tighten it using the chuck key. Place the end of the hole saw bit on the dot (or pilot hole) and begin drilling. Once the bit of the hole saw has made it’s way through, stop the drill and gently place the saw part of the hole saw against the control panel. Start the drill back up slowly gradually picking up speed. Please be away that you might incur some “jerking” at this point which is why it is so important to secure the control panel. Once the hole saw has gone completely through you now have a hole for your new button.

Here are some quick pointers to keep in mind during this process. Please wait a moderate amount of time before removing the inner piece from the hole saw after you finish cutting your hole. The hole saw can become very hot during the cutting process and can burn you if you touch it too soon after completion. Use a small screwdriver to remove the inner piece by inserting it into one of the slits on the side of the hole saw and pushing it down. If the control panel you are cutting into is metal, be careful of metal shards that might be protruding from the hole. You can use a utility knife and a file to eliminate the shards and clean up your button hole. If the control panel you are cutting into is wood, watch for smoke as you saw into it. If you do see smoke, slow the rotation of the drill down to keep from burning the wood.

Now that you have successfully made a button hole in your control panel, you can proceed with inserting the push button. Start by placing the button through the top your newly made hole. Take the button nut and tighten it on to the button until it is firmly pressed up against the bottom of the control panel. The best way to ensure that the nut is tight on the button is the use a button wrench which you can purchase from Bob Roberts. Next, install the Cherry switch by pushing it on to the bottom of the button. Make sure that the actual switch part of the Cherry switch is facing the top of the push button. You have now completed the task of installing a push button on your control panel. If you need help wiring the push button after installation, please see our post on Wiring A Push Button.

With the advent of standardized wiring schemes such as JAMMA, knowing how to install a push button has become an important skill. Being familiar with this process will help you with swapping these types of boards in and out regardless of the button configuration of your cabinet. Please feel free to make leave any questions or suggestions in the comments section below.

While replacing a plug on a power cord can fix some issues, there might be times when you find that the cord itself is causing problems. Frayed and exposed cords can lead to inconsistent power issues with your arcade cabinet that can cause the parts inside to break down earlier than expected. In this post, we will discuss how to replace the power cord in your cabinet to ensure that your game is getting consistent power.

Replacing A Power Cord

http://www.youtube.com/watch?v=kaBJ-Dpw9Qc

If you read our previous post on Replacing A Plug On A Power Cord then you are probably somewhat familiar with working on power cords. Most of the power cords that you encounter will have three wires inside of a black sheathing. These wires are typically color coded with the black wire representing AC line (sometimes called live, load or hot), the white wire representing AC neutral and the green wire representing the ground. For wires that are not color coded, you can determine the line and neutral from the plug. The wider prong on the plug should represent AC neutral (or white wire) leaving the smaller prong to represent the AC line (or black wire).

Once we have determined what the wires represent in our current power cord, we can remove it from the cabinet. Instead of cutting the old power cord and splicing the new one into it, we recommend tracing it back to where it connects inside the cabinet. A common point of connection for power cords is an AC filter. These filters look like small, silver boxes that usually have three prongs that protrude from the bottom and two that protrude from the top. Each prong corresponds to one of the wires in our power cord. Usually the left prong will be the AC neutral, the center prong the ground and the right prong the AC line. In order to remove the power cord, we must desolder these wires from the AC filter.

Sometimes the wires might not be connected directly to the AC filter. For instance, the cabinet in our video has the black wire going through a fuse before it gets to the AC filter. In this case, we want to desolder the black wire where it connects to the fuse and leave the wire going from the fuse holder to the AC filter. This fuse can provide protection in the event of a power surge so it is best to leave it in there. Also, the ground wire in our video is connected to a braided wire that runs throughout the game instead of the AC filter. This is fine as long as we connect the ground wire from our new power cord to the same place in the cabinet. Please see the image below for more information.

Click Image To See A Larger Version

When you have removed the old power cord from the cabinet, we can install the new power cord. This basically just entails soldering the new power cord wires to the locations where we desoldered the old power cord wires. To make the installation your new power cord easier, we recommend getting one that comes with the sheathing partially removed from the end and the wires exposed. Once you have finished soldering your new power cord into your cabinet, your arcade game should power up without any issues.

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Inconsistent power issues can wreak havoc on the parts inside your arcade cabinets. Replacing frayed and exposed power cords with new power cords can help to ensure that your arcade games stay working for years to come. Please let us know if you have any questions or suggestions by leaving them in the comments section below.

Most of the time when we hear symptoms such as color bleeding or shadowing, our first thought might be to install a cap kit. While cap kits are known to solve problems such as these, it could just be that our convergence rings are out of alignment and need to be adjusted to correct the picture. In this post, we will discuss how to adjust the convergence rings on your monitor so that you can correct these type of symptoms as well as other convergence issues.

Adjusting The Convergence Rings

http://www.youtube.com/watch?v=eDuKddayX-E

Before we begin adjusting our convergence rings, it is important to note that the monitor must be on during the adjustment of these rings if you want to be able to see happening on the screen. With that said, make sure that you take the necessary safety precautions to keep yourself from getting shocked during the process. As we talked about in our post on Adjusting An Arcade Monitor, we would highly recommend either getting a friend or a mirror to help you with the adjustments. This makes it much easier to know what’s going on with the screen when you are making adjustments to the rings.

Our first step is to locate the convergence rings on our monitor tube. If you are looking into the back of your arcade cabinet, you may notice several sets of rings wrapped around the neck of the monitor tube. These are what we like to call the convergence rings. You might also hear them referred to as the purity rings as well. These rings are magnetized allowing them to direct the CRT electron beams to the desired locations on the screen. Before we actually turn the rings for the first time, it is a good idea to take either a lightly-colored paint pen or some correctional fluid and draw a line across the rings so that you know what your starting point is. You might also have a different color of pen or fluid handy to mark across the rings again once you have found the correct position for them.

Once we have made the mark across the convergence rings on our monitor tube, we can begin adjusting them. If your PCB has a video test mode for convergence available, we would recommend putting the game in that mode so you can easily tell when the convergence is correct. Watch the screen as you slowly turn each ring until you feel that the picture is correct. When you have adjusted the convergence rings to your liking, you can mark across them with the other pen or fluid that we mentioned above. If you don’t plan on making any more adjustments on the rings, you can also take some glue and apply it across the rings to hold the adjustments into place for years to come.

Color bleeding and shadowing is a pretty common problem with arcade monitors in general. Before you decide to install a cap kit on your next monitor with these issues, you may try adjusting the convergence rings as the starting point for your repair. If you have any other comments, questions or suggestions about adjusting the convergence rings, feel free to leave a message in our comments section below.

Just like most console video games, arcade games have different options that you can adjust in order to change the gameplay experience. Options such as difficulty, number of lives and number of plays per coin are just some of the options that can be changed on your arcade game. While newer arcade games usually use service menus for these adjustments, classic arcade games typically use a set of switches on the board known as DIP switches. In this post, we will discuss how to adjust these DIP switches so that you can customize the gameplay experience to your liking.

Adjusting Dip Switch Settings On A Board

http://www.youtube.com/watch?v=Q0evRVo8WM4

Before we can adjust our DIP (or Dual In-line Package) switches, we must first locate them on our board. Take a look at your board and see if you can find a set of switches all in a row. The DIP switches themselves should be one of two styles: slide or rocker. Slide style DIP switches have a small plastic square that “slides” to indicate the on or off position. Rocker style DIP switches “rock” down or up to indicate the on or off positions respectively. In our video for this post, we demonstrate how to adjust slide style DIP switches but the process is very similar for rocker style DIP switches as well.

Once we have located our DIP switches, we can begin adjusting them. Please note that DIP switch settings are typically only read when the game boots up. As such, make sure your game is turned off when adjusting the DIP switches then turn the game back on for the settings to take effect. Please do not blindly try and adjust these DIP switches as doing so could lead to undesired results. The manual for your game should contain all of the information you need to know about which DIP switches control what settings. If you do not have a manual, please check out the sites below for help locating one.

Arcade Manual Sites:

• The ARCade ARChive – http://arcarc.xmission.com/
• Crazy Kong Manuals – http://www.crazykong.com/manuals/
• Textfiles Arcade Manuals – http://pdf.textfiles.com/manuals/ARCADE/
• MikesArcade.com – http://www.mikesarcade.com/arcade/manuals.html

Depending on the setting you are trying to change, you might have to adjust multiple DIP switches. For example, the first four switches on your DIP switch might control the amount of coins per play. Your manual should indicate how to set each of these in order to achieve the desired setting. If you are trying to set your game on free play, the setting might be related to the coins per play switches or it could be on a separate switch altogether. Also, some of the games that you encounter might not have a setting for free play in which case it might just be easier to install a credit button which we will discuss in a future post.

Whether you are an arcade operator that needs adjust the coins per credit settings or a collector that likes all of their games on free play, adjusting DIP switches is a valuable skill. Just remember to always consult your manual before adjusting them to make sure you achieve the desired effects. Please leave any questions or suggestions in the comments section below.

Back when arcade games first came out every game had a different wiring scheme which made trying to swap a board from one game to another a very difficult task. This problem compelled the arcade manufacturers to get together to create a standard and thus the JAMMA standard was born. In this post, we will help you get familiar the JAMMA standard.

Getting Familiar With The JAMMA Standard

http://www.youtube.com/watch?v=poL25IlGT_w

Before we get started, I would like to mention that I have posted a printable version of the JAMMA pinouts for your convenience. This will come in very handy if you are dealing with JAMMA at any point in the future. Please click the link below to access this document.

http://www.arcaderepairtips.com/jamma.html

JAMMA is a wiring standard that was developed to make switching arcade boards from one arcade cabinet to another easier. JAMMA stands for Japanese Arcade Machine Manufacturers Association and was developed in 1985. Any arcade game that predates this will not be JAMMA and even some games after this are not JAMMA. We recommend checking your manual or the internet before assuming that your arcade board is JAMMA.

A JAMMA harness is composed of a 56-pin connector (28-pins on each side) with wires coming from each of the pins. There are two sides of a JAMMA connector: the parts side and the solder side. The parts side of your board contains all of the surface mounted components while the solder side just contains traces and solder dots. It is important to identify which side is which so that you don’t plug your board in the wrong way. As luck would have it, many JAMMA connectors are labeled so that you can easily identify which side is which along with what each pin goes to.

If your JAMMA connector is not labeled with the pinouts, your first task will be to identify where pin 1 is located. The easiest way to located pin 1 is to use pin 7 which is known as the key and is usually blank. Once you have located pin 7, you’ll noticed that it divides the harness in two 2 halves. The shorter half (pins 1-6, A-F) should contain pin 1 along with all of the wires that go to your power supply. While these wires usually go straight from the power supply to the board, you might notice that someone has jumpered off of them to send power to another part of the cabinet. This is fine and a common practice.

As we look at the longer half of the connector, you will notice some wires going to the monitor. These wires (pins 12-14, N-P) are used to send the display signal to the monitor. There should be a wire for each of your colors (red, green and blue) along with a sync wire and a ground wire. If we look further down the connector, we will find the wires for our joysticks and buttons (pins 17-26, U-d). All JAMMA harnesses support 2 players, however, they might not have the all wires hooked up for each of them. Games that have more than 3-5 buttons per player or more than 2 players usually require a kick harness to work properly. A kick harness is an extra harness that attaches to the board along with the JAMMA harness to allow for the extra inputs.

You might also notice that there are not enough ground wires located on the connector to wire up all of your arcade controls. In this case, you will need to use a technique called daisy chaining. Daisy chaining is a wiring scheme that consists of jumpering a wire off of each connector so that the ground signal will carry over to the next connector. We’ll talk more about daisy chaining when we talk about control panel wiring.

JAMMA wired arcade cabinets take the work out of switching boards between cabinets. In face, the majority of the arcade games that you see today are wired using the JAMMA standard. Knowing the JAMMA standard will carry you far in your arcade repair endeavors. Please leave any questions or suggestion in our comments section below.

The majority of problems you will encounter with arcade monitors will involve working with the monitor chassis. In order to properly work on or repair a monitor chassis, we must be able to remove it from our arcade cabinet. In this post, we will discuss how to remove and install a monitor chassis from an arcade monitor so that we can make any necessary repairs to it.

Removing And Installing A Monitor Chassis

http://www.youtube.com/watch?v=BNnbEPY7DVM

Before you begin, we recommend unplugging or turning off the power to your arcade game. As we’ve talked about in previous posts, monitors hold an extremely high amount of voltage which can be very dangerous to you should you come in contact with it. Always be safe and take the time to make sure that your arcade game is unplugged when working with the monitor.

On that same note, the first thing we are going to do when attempting to remove a monitor chassis is to disconnect the power wires going to it. Most games use a Molex connector between the power supply and the monitor chassis which allows for a clean and easy disconnect. If your monitor chassis doesn’t have this Molex connector, you might need to cut the wires in order to remove the chassis. If you end up cutting the wires, you might consider installing a Molex connector to make it easier on you in the future. Please see our post on Installing A Molex Connector for more information.

Once we have disconnected power from the arcade monitor, we can remove the anode cup from the tube. Removing the anode cup is very similar to discharging the monitor. The main difference is that instead of just sticking the screwdriver up underneath the anode cup and waiting for a pop, we are going to use the screwdriver to push the prongs of the anode cup together so that we can remove it from the tube. For more information on this please see our post on how to Safely Discharge An Arcade Monitor.

Now that we have removed the anode cup from the tube, we can move on to unplugging the neck board. The neck board is connected to the very back end of the tube. It is usually a square circuit board and has wires connected from it to the main chassis. It might also have a ground wire attached to it from the monitor tube. If it does, make sure that you cut or unplug this wire before trying to remove it. The neck board should come off pretty easy with just a light amount of force. Sometimes you might find that someone used silicon or another adhesive to keep the neck board in place. It is best to remove this before trying to remove the neck board.

With the neck board unplugged, we can now locate and unplug the degaussing coil and yoke wires from the monitor chassis. The degaussing coil runs around the monitor tube and plugs into the monitor chassis via a two prong connector. The yoke wires come off the monitor tube and attach to the chassis via a four prong connector. The connector for the yoke wires is usually keyed with a wider space between one of the outside pins and the rest to make it easy to hook up. If your monitor chassis has two places where the yoke wires can plug in, make sure to remember which set of pins you removed it from. Locate and unplug both sets of connectors.

Next, we are going to located and detach the video wires coming from the board or PCB. These wires are responsible for making sure that your monitor gets the image the board is sending it. Sometime these wires might be split into multiple connectors. Make sure that you notice how these connectors are plugged in before attempting to remove them. Locate this connector and remove it from your chassis.

After all of these steps have been completed, you should be able to unscrew the chassis from the mounting bracket and remove it from your arcade cabinet. If your ground wire was not attached to your neck board like we talked about earlier, make sure that you detach it from the chassis before attempting removal. With your chassis removed, you can now take steps to repair it or send it off.

Installing the chassis back into your arcade cabinet is as easy as doing these steps in reverse. One item to note is that your neck board is keyed and only goes one way. Make sure that you look at both the back of the tube and the neck board so that you can line them up correctly to each other. If you have any questions or suggestions about this post, please leave them in the comments section below.

Sometimes when you move a game you might find that your monitor has some areas of discoloration or that your once bright colors now appear somewhat washed out. This might be due in part to some unwanted magnetic fields interfering with your screen. In this post, we’ll discuss how to use a degaussing coil to solve the issues caused by these fields.

Using A Degaussing Coil

http://www.youtube.com/watch?v=xboO2JUvtBM

Before we get started, let’s talk about what a degaussing coil does. The job of the degaussing coil is to demagnetize the shadow mask which is similar to a metal mesh plate located inside your tube. The holes in this plate are aligned to ensure that the electrons from the red, green and blue cathode guns reach the same colored phosphors on the monitor. Should this plate become magnetized, the color and focus of your screen can suffer. Hopefully by demagnetizing the shadow mask you can solve some of the discoloration and focus problems you might be having. Please see our links below for more information on purchasing a degaussing coil.

Buy a Degaussing Coil (CRTs Less Than 19″) from MCM Electronics now!

Buy a Degaussing Coil 13″ Pro from Bob Roberts now!

Once you have purchased a degaussing coil, you can begin the process of degaussing your monitor. First off, make sure that you have the degaussing coil plugged in and that the power to your arcade game is on. Take the degaussing coil and hold it to the center of your monitor screen. Press the button to active the degaussing coil and move it in small circles across the front of your monitor. Slowly begin to widen the circles as you back away from the monitor. As you do this you will notice the degaussing effect on the monitor start to dwindle. Keep repeating the circles until the coil has no effect on the monitor then release the button. You have now completed the process of degaussing your monitor.

At this point, you might want to check your screen to see if it made a difference in your picture. We sometimes repeat this process if we didn’t get the desired effect the first time. Remember that this process can be used for any CRT based screen not just arcade monitors. If you have any comments, questions or suggestions about degaussing a monitor please leave them below.

When a monitor just has a black screen, it’s a pretty good indication that it’s not getting power. The typical places to start with this kind of issue would be the power cord and the HOT, but lets say that you’ve checked them and they are not your problem. Where do you go from here? In this post, we will discuss how to check diodes on your monitor chassis to make sure that they are in working order.

Checking Diodes On An Arcade Monitor

http://www.youtube.com/watch?v=u4l-kosl0vg

The diodes we are talking about are located in the power supply section of your monitor chassis. There are usually about 4 or so located right in a row in this section. Examine your monitor chassis and see if you can find them. In the video, ours were located near a large capacitor. Once you have located these diodes, you can check to see if they are shorted or not.

Before we begin, you might want to refer back to our post on Checking Fuses With A Multimeter to get familiar with the diode test settings on a multimeter.

The process of checking a diode is very similar to checking a fuse except that the indicators are reversed. When we checked fuses, we wanted our meter to generate a long beeping sound or a 0 (ZERO) ohm reading. If our meter reads this while we are checking a diode, this indicates that it is shorted and is not working properly. Shorted diodes can be caused by many things including hooking up power to an arcade monitor that requires an isolation transformer. Always be sure that you are using an isolation transformer on monitors that require it.

If you find a shorted diode, you need to replace it. Desolder it from your board using your desoldering iron or solder wick and solder the new one into place. Always make sure that you replace the shorted diode with another one that has the stripes oriented exactly like the original diode. Also, be sure that all of your power wiring to your monitor is correct before turning it back on. Doing this will save you from damaging another diode and having to repeat this process over again. Once you have replaced these shorted diodes you are finished with this part of your repair.

Sometimes a black monitor screen can mean more than just a power cord or HOT issue. Knowing to check your diodes before moving on to more complex repairs can save you lots of time and effort. Please feel free to leave any questions or suggestions in the comments section below.