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Main => Monitor/Video Forum => Topic started by: Mattreyu on April 04, 2016, 09:08:58 pm

Title: CRT magnetic interference issues
Post by: Mattreyu on April 04, 2016, 09:08:58 pm
Hey guys,

I have a new billabs crt bl25c90t multisync that I just installed In my upright mame cabinet. This thing is HYPER-SENSITIVE to emf! The dinky factory cabinet speakers immediately had to be removed because of interference.  I've tried various shielding techniques  on the speakers and then have tried different factory-shielded speakers with small magnets and nothing seems to be too small or shielded to interfere with this monitor. Hell, my fender electic guitar amp/was effecting it from halfway across the room.  This is my third monitor in this machine over the years (original, a tv crt and now this billabs.) And I've never had this problem with the stock speaker setup. 

Anyone have any tips or advice for this? I've cosidered wrapping the frame in magnetic-shielding material at about $26 a square foot, but that still doesnt protect the front of the monitor from dangerous fridge magnets that might be lurking a mere room away.


Thanks in advance.
Title: Re: CRT magnetic interference issues
Post by: grantspain on April 05, 2016, 10:47:20 am
is the monitor auto or manual degauss,do you hear it make the degauss noise when you power it on?
Title: Re: CRT magnetic interference issues
Post by: Mattreyu on April 05, 2016, 08:53:26 pm
I honestly dont know. It's entirely analog - there's no provisions for a manual deguass. As for automatic deguass at power on I don't know either. The distortions caused by the offending emf(s) dissipate after they're removed from the equation, so maybe... although there isn't the typical "dwwwoinggg" sound at powerup that usually indicates an auto degauss...

my real problem is not deguassing, as I can do a manual with the ol soldering gun... my problem is, it seems this monitor's own magnetic directional field is so weak itself, such that the slightest emf from any source is enough to cause clouding, color distortions, etc.  Keep in mind, when not bring interfered with, the picture is strong and color perfect. I'm not an elctronics guru by any means, just seems so Impossible that this monitor could have ever been used in arcade cabinets or in any application with speakers, transformers, cooling fans, other nearby equipment, etc... which leads me to believe there has to be some problem. I guess my neophyte theory would be, is there an adjustment to increase a monitor's own field to negate outside interference?

currenty, my machine is speakerless, dragged in the center of the man cave, away from wall wiring, outlets, other devices, and anything with a speaker has been dragged to the other side of the room 15 to 20 feet away. This is the only way I can keep the image clean. And no, I'm not exaggerating,  it is really that bad\sensitive.