follow the speaker wires back to the chassis.
look for the cap, solder joints and maybe a bad
audio IC.. if you have component cooler you can
spray the IC while operating, if the noises stops
for a moment while the chip is cold then its the chip.
etc..


Joe R. wrote:

I am working on a Hitachi projection TV, model # 50ux7k, which has
developed a very loud cracking/popping sound coming out of the
speakers. All of the TV's sound functions and video functions work
correctly. There is no change in the television's picture or sound
when the cracking/popping noise is present. The loud cracking/popping
noise is not affected by any of the sound controls. You can turn the
TV volume all the way down, and the cracking/ popping noise stays the
same. Changing the mode (Matrix/Hall/Dolby) does not affect the loud
noise. I'm not sure where to start looking for the problem. Since the
television's sound and picture are not affected by the noise, I think
I may be looking for a bad cap, poor solder connection, or some other
source of feedback into the signal board. I am hoping that someone
else has run into a similar problem on Hitachi Projection TV's that
can point me in the right direction. Any help would be greatly
appreciated!