JVC TV audio out hum

[Rockmore]

I have a JVC 27S33 tv with rca component outs on the back. The audio out all of a sudden puts out a audio hum regardless what amp or receiver it's connected to. Have tried everything to try and isolate the problem: changed location/outlets, rca cables and types, etc etc. It's definitely with this tv's audio out. There is no other problems what so ever including audio using the little speakers in the tv itself. It's just the rca audio outs (putting out a hum with the audio signal). Have dissembled the unit several times, and everything is on one main circuit board, with a additional small circuit board on the back of the CRT neck itself. Solder connections all look shinny and clean where the audio out rca female jacks are. There are absolute micro size resisters in solder joints extremely close to the rca joints. What to do to get rid of the hum? Thanks Happy Holidays

[Larry at Approved]

Assuming you are connected to your local cable tv company, you probably have a ground loop. disconnect the cable box from the input to the tv and see if the hum goes away. if it does, you need to get a ground isolator for the coax line. this is an inexpensive device that isolates the cable ground from the tv ground. the problem occurs because the cable company ground connection is not the same as your electrical system ground, creating a difference in potential, hence a ground loop and hum.

[Rockmore]

thanks larry - not even close. no cable tv or cable converter box at all. spent two full days isolating where the hum was coming from, and it's definitely and soley from the audio outs on the tv. its not a rca cable problem(s), its not an outlet or ac polarity problem(s), its not any sort of RF interference problem causing the hum from cheap unshielded cables, its not from any other component like the DVD, CD player, etc. Using a good fully checked out new dtv converter box. In fact I have two of them both new Ive fully checked out that are different makes and models. To eliminate all the specific details I went through in the past two days, believe me its the tv's audio outs.

[Larry at Approved]

does it hum with no dtv converter box connected? if it's not humming through the tv speakers, it almost has to be some sort of ground problem. the preamp output of the tv should be tapped off in the audio circuit on the way to the tv's speakers, so unless there was a broken ground at the low level output jacks on the set, the tv speakers should hum also. strange.