EDIT: I realized while editing that the original linearity coil was installed backwards. It can be installed either way (with the adjustment piece facing forward or backward) and someone removed it at some point and reinstalled it backwards. I removed the replacement coil and reinstalled the original in the correct orientation and....it fixed the issue just as the replacement coil did. So the coil was simply installed backwards by someone at some point and having it like that causes linearity issues. Learn something new everyday. Thanks for watching!
Linearity coils are coils with a ferrite material and a magnet on it. This is so they only affect the current in the yoke on positive or negative side, depending on which way they are installed. This is done by having a static magnetic flux (either positive or negative, depending on the orientation) from the magnet in the ferrite. The current in the coil that produces flux with the same direction will saturate the core and lower the inductance and that is how the linearity coil only affects one side of the picture. Measuring inductance won't show you this effect. As you suspect somebody has swapped the orientation of the coil and that is why it was affecting the wrong side. btw, by adding magnets to this coil you can change how the linearity coil behaves and fix linearity problems. In your case though since both sides are squished this may be a problem caused by the S-capacitors.
Those horizontal coils are notorious for braking as someone who works on Hantrex and Intervideo chassis they all have these useless things, many of time when i have one in for repair its either snapped and glued back together or loose on the chassis, the legs underneath detach from the coil this then messes up the windings you always know when ones faulty as they produce a ringing sound and horizontal linear issues luckily i have a draw full of new ones and swap them out.
I came to this video while searching for info on adjusting linearity on CRT TVs and it just makes me wonder if there’s some way to adjust the type of (seemingly) non-adjustable horizontal linearity coils they tend to have. Sure would make playing games on them a lot more enjoyable. Some CRT TVs have great linearity, but others are atrocious. And the ones with digital service menus never, ever have an adjustment option for hor. Iinearity! So frustrating.
Try adding various different magnets to the top of the linearity coil. That should help adjust any offset. That’s essentially what’s happening here when the core is being adjusted.
Hey Mike im having some issues with a 25" polo and was wondering if you had any ideas. I have rejuv'd the monitor and its checks out well with the machine. The problem is the monitor is very dim, i can cut the flyback up and the brightness and it just washes out the colors. If played in a dark room its not bad, but compared to my other machines i know something is not right. Any idea's? Board was recapped and made little to no difference. Thanks
EDIT: I realized while editing that the original linearity coil was installed backwards. It can be installed either way (with the adjustment piece facing forward or backward) and someone removed it at some point and reinstalled it backwards. I removed the replacement coil and reinstalled the original in the correct orientation and....it fixed the issue just as the replacement coil did. So the coil was simply installed backwards by someone at some point and having it like that causes linearity issues. Learn something new everyday. Thanks for watching!
i was about to mention that 😅
Linearity coils are coils with a ferrite material and a magnet on it. This is so they only affect the current in the yoke on positive or negative side, depending on which way they are installed. This is done by having a static magnetic flux (either positive or negative, depending on the orientation) from the magnet in the ferrite. The current in the coil that produces flux with the same direction will saturate the core and lower the inductance and that is how the linearity coil only affects one side of the picture. Measuring inductance won't show you this effect. As you suspect somebody has swapped the orientation of the coil and that is why it was affecting the wrong side.
btw, by adding magnets to this coil you can change how the linearity coil behaves and fix linearity problems.
In your case though since both sides are squished this may be a problem caused by the S-capacitors.
Thanks for the video Mike. I've come across many Hantarex chassis and met this problem. Didn't thought this coil could cause issues like that.
Smeggin awesome documentation and update sir !
Those horizontal coils are notorious for braking as someone who works on Hantrex and Intervideo chassis they all have these useless things, many of time when i have one in for repair its either snapped and glued back together or loose on the chassis, the legs underneath detach from the coil this then messes up the windings you always know when ones faulty as they produce a ringing sound and horizontal linear issues luckily i have a draw full of new ones and swap them out.
Who would have thought. Keeping those extra parts around did help a little in this instance.
I was paying close attention because of my Polo.
Nice work sir
I have the same problem with a Nanao ms8-26. I'll see if changing the coil fixes mine!
Great thats how a video should be done 👏👏👏👌👌
I came to this video while searching for info on adjusting linearity on CRT TVs and it just makes me wonder if there’s some way to adjust the type of (seemingly) non-adjustable horizontal linearity coils they tend to have. Sure would make playing games on them a lot more enjoyable. Some CRT TVs have great linearity, but others are atrocious. And the ones with digital service menus never, ever have an adjustment option for hor. Iinearity! So frustrating.
Try adding various different magnets to the top of the linearity coil. That should help adjust any offset. That’s essentially what’s happening here when the core is being adjusted.
Hey Mike im having some issues with a 25" polo and was wondering if you had any ideas. I have rejuv'd the monitor and its checks out well with the machine. The problem is the monitor is very dim, i can cut the flyback up and the brightness and it just washes out the colors. If played in a dark room its not bad, but compared to my other machines i know something is not right. Any idea's? Board was recapped and made little to no difference. Thanks
Wonderful but an experience
I love Polos, but they can be so weird sometimes
Which mortal kombat is this with the test grid option?
They all have it.
hey mike.. do you have a website or a way to contact you?
i'm a complete novice and i'm running into some issues and wondering if you have any advice
Sure. Mikesmonitorrepair@yahoo.com