Using A Degaussing Coil

Using A Degaussing Coil

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

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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.

Frys Electronics - Buy Now! Buy a GC Throsen 9317 High Power Degaussing Coil from Frys Electronics now!

The Real Bob Roberts - Buy 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.

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    Good job!! Great video

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    If you have a pacemaker, stay far far away from degaussing coils

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    Hey guys. Great info! I have four 19″ monitors and one 25″ monitor. Will the 19″ coil still work on the 25″ monitor? Or do I need to buy the bigger coil? And, will that the bigger coil be ok on my 19″ monitors?

    Thanks in advance.


  4. Avatar
    Jonathan Leung


    The smaller degaussing coil should work fine for all of your monitors. For some reason lists this degaussing coil as only working on 19″ monitors or smaller but we have successfully used it for pretty much any size tube. Of course, the bigger the coil you get the more of an effect it will have on the monitor but overall any degaussing coil you get from a reputable source should work on all your monitors.

    We have also featured your question on episode 7 of our Q&A podcast. Please listen to it for more of our thoughts on your question. Thank you for your question and good luck with your future repairs.

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    I have a brand new 19″ monitor installed on my ms pac man upright cabinet. The monitor looks great except on the top and bottom right hand side the color is off. I have tried a degaussing coil many times with no luck. I don’t know what else to try. Does anyone have a suggestion? Its a bummer because I have spent a lot of time restoring this cabinet and to have the color messed up in those corners is a dissappointment after all the money I spent. I appreciate your help.


  6. Avatar
    Jonathan Leung


    We have had problems with discoloration in sections of our monitor due to rebar running through the concrete foundation of Tim’s gameroom. One thing that seems to fix this problem is if we rotate the position the game is facing. While this may be a long shot answer, it’s definitely worth a try. You could also have a problem with the shadow mask in your tube. Check out this Wikipedia article for more information: Since your monitor is relatively new, you might trying contacting the manufacturer and see what their thoughts are on your problem as well.

    We have also featured your question on episode 10 of our Q&A podcast. Please listen to it for more of our thoughts on your question. Thank you for your question and keep us updated on your progress.

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    I just bought a classic Ms. Pacman… and it turns on and everything… but I can’t seem to play it…. Help… I can’t access the credits for me to play… any instructions…

  8. Avatar
    Jonathan Leung


    There are a couple of ways you can give your Ms. Pac Man game credits:
    1.) If you can open your coin door, you should see a coin mechanism attached to it. At the bottom of this coin mechanism should be a small, thin piece of metal that looks like a paper clip. If you push this piece of metal down and to the side it should simulate giving the game a quarter and allow you to play.
    2.) You can wire a push button to the wires that attach to this part of the coin mech to allow you to coin it via the button instead of pushing the wire down. Some games have a service credit button that will do the exact same thing located just inside the coin door so you might check for that.
    3.) You can set your dip switches to free play so that you don’t have to coin up the game to play it. If you set dip switches 1 and 2 to the On position on your Ms. Pac Man board that should give you this option. Please see our post on Adjusting The Dip Switch Settings On A Board for more information.

    We have also featured your question on episode 17 of our Q&A podcast. Please listen to it for more of our thoughts on your question. Thank you for your question and good luck with your future repairs.

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