Arcade Monitor noise

poodude · Post by **poodude** » Sat Jun 21, 2008 12:57 am

So... I had my monitor sitting in my Astro City cab in a vertical position and was working and sounded fine. Then I decided I would like to start playing horizontal games again, so I took off the 4 bolts, turned it 90 degrees and slid it back on, and screwed the bolts back on. I didn't ruin the monitor into anything or drop it etc; I just turned it.

Now when I turn on the power I am hear a high pitched noise. If I touch the monitor with my hand, the pitch of the noise changes. I then took the monitor out of the case and set it on a wood board to inspect as it was on. It seems like the sound is either emitting from the back of the tube or on the board itself. With gloves on, I waved my hand over the back of the tube and the noise changed pitch.

I also tried pressing the "demag" button on the power supply.

Does anyone have monitor experience to know what this is? Is it just interference of some kind that can be corrected? There wasn't anything else in the room when I tested it, that could have interfered with it.

Post by **Dave_K.** » Sat Jun 21, 2008 3:55 pm

As far as I know its normal, and an indication of an aging monitor, or rather aging flyback which is the tall black block with red anode wire coming out of it. If you leave the monitor on for awhile I bet the noise will go away after warming up...unfortunately it will only get worse or over time. I have the problem too, although very slight at this point on one or two of my cabs. Turn up the game sound and you won't hear the high pitch noise anymore.

poodude · Post by **poodude** » Sat Jun 21, 2008 5:00 pm

It does sound like its comming from the flyback, so you're probably right. I wonder if those can be swapped out with new ones that don't make as much noise.

Post by **Dave_K.** » Sat Jun 21, 2008 10:16 pm

Yes, you can swap out the flyback, but its usually the most expensive part on a monitor chassis...not to mention you'd need an exact replacement for your model chassis (and if its a japanese nanao they're not exactly easy to source).

jonny5 · Post by **jonny5** » Sat Jun 21, 2008 10:21 pm

i have one for sale right now....well...actually a full used chassis.....nanao ms29 sa

no issues with the flyback but the neckboard needs a cap replaced

i will hook ya up with a good price...drop me a PM and we can discuss

im open to trades as well

poodude · Post by **poodude** » Sun Jun 22, 2008 6:23 pm

PM sent.

I was also curious about the knob settings on the flyback transformer. I got sticky fingers and decided to adjust them to see what would happen. I got lovely horizontal white lines across the screen. I then readjusted them until the monitor went back to black.

Anyone know what the proper knob settings of the flyback should be?

Post by **Dave_K.** » Sun Jun 22, 2008 8:17 pm

Flyback has 1 or 2 knobs (depeneding upon the chassis). The knob you turned is called "Screen" which regulates the screen voltage. You should almost never need to adjust this, but if the brightness is cranked all the way (as well as RGB biases) then you can try adjusting this. You can also think of it as setting the black level. Sounds like you have it set properly where the black looks black enough with the monitor on, and no lines.

The other knob sometime found on a flyback is for "Focus" which does exactly that.

poodude · Post by **poodude** » Mon Jun 23, 2008 6:20 am

Thanks for the info Dave_K! I'm new to the arcade hardware scene, so all of this is new to me.