Quieting old CRT's

[Tiberian Fiend]

Is there any way to quiet old CRT monitors? I bought an old Sony Trinitron 29" video monitor on Craigslist, and it whines quite loudly. Is there anything I can do to quiet the whine? I don't think it's the broken kind of whine, just the "old television" kind of whine.

 

[RetroHacker_]

First, figure out where the sound is coming from. Usually, the problem is simply a loose core in the flyback transformer. Take the cover off, and listen to the sound while it's on. Poke the flyback with an insulated plastic object (like a plastic pen barrel) and see if the sound changes. If it does, then try resoldering the flyback - when that doesn't work, you can use something like a wooden toothpick and jam it in between the flyback core and the plastic housing.

I've also seen other small transformers do this. Again, you can quiet them by preventing them from oscillating with some kind of wedge.

-Ian

 

[deadcrickets]

I would urge extreme caution when dealing with old CRTs compared to LCDs. They can retain charge for days after being unplugged. Enough charge to kill you instantly if you touch the wrong thing.

 

[Lutiana]

I would urge extreme caution when dealing with old CRTs compared to LCDs. They can retain charge for days after being unplugged. Enough charge to kill you instantly if you touch the wrong thing.

Tru dat, nearly took out my dad way back when. He and I were trying to fix our CGA monitory and he touched something on the tube and nearly flew across the room. The fly back transformer is very dangerous, so be very careful.

 

[Tiberian Fiend]

I don't think it's the flyback transformer. I had a monitor that had one go bad, and it was a lower-pitched whine. This is the penetrating, higher-pitched whine that televisions generally emit (I have a cheap Wal-Mart television that emits the same whine, just not as loudly).

I'll have to take a poke around inside the case when I get the chance to to see where it's coming from.

 

[Chuck(G)]

Could also be the deflection yoke. Usually, these are composed of two windings on a two-piece ferrite core.

You can also get a whine from a corona leak. With the lights in the room out and the face of the CRT masked so that no light gets out, you can sometimes see a faint purple glow either in the flyback transformer or the anode lead that comes off of it where the leak is occurring. A blob of corona "dope" can clear the right up.

If the CRT has any sort of a shield around it, check that for noise also. Sometimes these whines can be hard to track down. On the other hand, if you wait until your 80th birthday, your high-frequency hearing will deteriorated sufficiently that you won't hear it. So, as a last resort, you can put the monitor into storage for a few years....

 

[Tiberian Fiend]

Well, it's going into a homebuilt arcade cabinet. Maybe I could put some soundproofing foam as lining around the monitor. The easiest way to get rid of a noise is to cover it up.