mark1101 Posted January 7, 2009 Share Posted January 7, 2009 I found this by accident with my RTA system when I was measuring my room. A spike right at 15.75 Khz at 80db at the back of TV........72db 12 ft. away in the room. Ever hear of something like this? What can you do about it. I gave it a few love taps and nothing happened. It is a 36" Panasonic tube TV about 10 years old. Still works perfectly. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted January 7, 2009 Author Share Posted January 7, 2009 After reading a bit on the net I think it could be the NTSC spec horizontal sync frequency for TVs which is at 15735hz. Somehow it is getting audible in the room. If anyone knows how to eliminate this issue please let me know. Thanks Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 7, 2009 Share Posted January 7, 2009 I found this by accident with my RTA system when I was measuring my room. A spike right at 15.75 Khz at 80db at the back of TV........72db 12 ft. away in the room. Ever hear of something like this? What can you do about it. I gave it a few love taps and nothing happened. It is a 36" Panasonic tube TV about 10 years old. Still works perfectly. Mark that is close to the Horizontal Sweep Rate Frequency in the television and can be caused by minute vibrations from many sources in that area of the chassis. I've found it to be caused by loose screws, a transformer core vibrating or the way it's mounted allowing this to happen and other possibilities. It wasn't unusual for me to service a television because a Women in the home can usually hear this and are often very bothered by it while it often went undected by the husband if middle aged or older who sometimes could hardly hear it if at all. Sometimes just flexing the chassis or wedgeing something under the chassis (non-conductive!) could help stop it if you don't want to have it serviced. mike tn edit: Mark if your comfortable taking the TV apart you can sometimes take an insulated probe and press around in the horizontal/high voltage area of the television and locate the problem. Be aware though that sometimes when the TV is taken apart the chassis is then flexed and in a different position and the noise will go away only to return later after it is assembled again. Caution: There is Very high voltages in this area that can be dangerous so only take it apart if you are comfortable working with high voltages. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted January 7, 2009 Author Share Posted January 7, 2009 Mike, Thanks for posting. I gotta say this is the dog gone funniest thing I never knew about. I have the RTA running and just about picked the TV up and dropped it. I've done everything that I'm willing to do as far as movements and positioning.....I'm surprised I didn't just break the TV with what I've been doing to it. The tone got up to 93db at one point with the mike right at the back of the TV. Sound is strongest at the back. You should have seen me going around the room trying to find the source of the tone at first. It was pretty frustrating. Took about 30 minutes to eliminate everything. I was certain I had a problem with my amp. But it is very clean. Dang old TV. I'm sure I've gotten a few headaches from this over the years and had no idea at all what has been going on. No one in our house has ever noticed this....or said anything about it. My wife or daughter ever said anything about it. We recently got a new HDTV and moved this set to the basement (where I am now). Maybe this started after the move. I have no idea. Thanks for the help. Quote Link to comment Share on other sites More sharing options...
toddvj Posted January 7, 2009 Share Posted January 7, 2009 I've always been able to tell if a TV is turned on in a room even if it is muted, because I can hear the buzzing sound. Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted January 8, 2009 Moderators Share Posted January 8, 2009 WOW never heard of that I guess there are some small benefits to having older ears after all. Mark, you have had some strange things happen, this kind of crazy stuff is enough to give you a headache . Quote Link to comment Share on other sites More sharing options...
Mr. RF62 Posted January 8, 2009 Share Posted January 8, 2009 I have the same thing happening, coming through my centre channel which is on top of the T.V. Soon as I turn it on, the sound comes, turn it off, it goes away. Tried aluminum foil between for the fun of it, no good. I'll have to move the speaker, thats all. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.