Very noticable 15Khz high-pitch tone (Hantarex Polo 28 STAR)

[arcadeswede]

Hi everyone!

I have a Hantarex Polo 28 STAR. I got it from a friend who needed to clear out his garage. He didn't know if it worked and the powercord was missing. Fixed a new cord, adjusted the screen colors/geometry (it's connected with VGA to my MAME PC) and now it display a very nice 15khz picture, IMO.

I'm used to televisions having this high-pitch tone since my childhood, no biggie, but this high-pitch tone from my Hantarex monitor is a little too much.

I've googled the "problem" to see if there was something I could do about it and a some people said it could be the flyback transformer. I don't know anything about what's inside a flyback but it was something about layers that handles the voltage inside the flyback can become loose over time and vibrate, therefore making the high-pitch tone more noticable.

A friend of mine asked me to turn down/adjust the flyback, so I did but nothing changed in the high-pitch tone.

I think the monitor is a tri-sync monitor (I'm only using 15khz though) but when I once tried 25khz, 32khz, the high-pitch tone was gone. I guess it has something to do with the human hearing range? Some people can't even hear the 15khz tone.
I guess it has to do with age 

Now to my question!
Is there something I can do to make this 15khz high-pitch tone go away or at least make it less noticable?

Here's a video where you can hear it. It's even more noticable IRL:

[baritonomarchetto]

The more noticeable sound you can hear in that video is you pressing those damn buttons...
Anyway, looks like the classic "frying" sound from the flyback, not a high frequency sound. The flyback is probably on its last legs, even if it could still work for a lot of time at home. Try eventually to act on the horiz freq. potentiometer to see if you have some effect.

[grantspain]

i can't hear it but then again i am a bit old
normally on the hanty polo range the frequency whistle is caused by either the anode wire too close to neck card or most likely a noisy linearity coil

[arcadeswede]

Try eventually to act on the horiz freq. potentiometer to see if you have some effect.

I'll try adjusting the H-pot and see if it changes anything.
If it does, is it a bad flyback? Is it worth replacing?
If it doesn't, what could it be?

normally on the hanty polo range the frequency whistle is caused by either the anode wire too close to neck card or most likely a noisy linearity coil

Is it possible to fix the linearity coil to make it less noisy or replace it?

[baritonomarchetto]

It's never worth to replace a flyback ALONE : there are a series of other components that should be replaced to ensure long life to the whole chassis.
Being that you have not a critical issue (i.e. sparks coming out of if) and, as said, yours could still work for years at home use, the flyback would be the last thing i would change.

[arcadeswede]

Being that you have not a critical issue (i.e. sparks coming out of if) and, as said, yours could still work for years at home use, the flyback would be the last thing i would change.

Alright! Thanks for the tip!


I took my shotgun mic and recorded an audiosample behind the flyback where the sound was most noticable. There's some fuzzzzing sound also somewhere, I don't know if that's normal or not but please have a listen. At 0:35 I really found the spot for the 15Khz tone and the sound at the end is just me starting the cooling fan.
https://drive.google.com/file/d/0B5bps08cRR5lX2JJVGVTdURQZUk/view?usp=sharing

I'm hoping to reduce this high-pitch 15Khz tone somehow and I would like to know if other people have this "issue" too.

[dmckean]

That might be normal for a big monitor, it's not too offensive. All the other noises on the sound clip sound much louder toe me. Maybe my ears are just getting old.

Can you hear it when it's mounted inside a cabinet?

[arcadeswede]

Can you hear it when it's mounted inside a cabinet?

Yes but I haven't finished the bezel for the monitor yet but that's just a piece of plexiglas in front of the monitor. I don't think that will eliminate the sound but maybe it's possible to isolate the chassie somehow?