Help! TV making loud poppin noise!  

Could be the coating on a high-voltage lead breaking down, with arcing to the chassis. Humidity aids this. Also, buildups within CRTs sometimes audibly arc. I sometimes heard such sounds from the three Heathkit color TVs I built, but nothing further happened. Replacing or repositioning h-v leads shouldn't be too costly, and the CRT is okay as long as you're getting images. Arcing within either the red, green, or blue CRT electron guns might damage them enough to shut one down, giving an unadjustable hue to images. But sometimes electrodes within these guns can be restored without removing the picture tube with CRT 'rejuvenation' equipment. Arcing can destroy CRT buildups, so normal operation continues. I'd stop using any set of mine with unusual burning odors present. -- John

Tough to say whether it's cold metal with moisture condensation, or high enough humidity still in the air--or none of this. Glad to hear it stopped. -- John

Cliff,
My Mitsubishi 40 started doing that at about 6 years of age. It ended up being the tube and not worth fixing. I complained to Mitsubishi and was rewarded with a good deal on a 50"RPTV.

FF

Unless your air conditioner is a swamp cooler, A/C's generally reduce humidity inside.

And since you're (likely) outside of warranty, now would be a great time to open up the case and blow out the dust. You might be surprised just how much gunk is in there! Use your air compressor or get some cans of compressed air, unplug it and let it rest for several hours, open it up, and blow away. Be careful, though! High voltages and all that; you're on your own; no warranty; you agree to hold AVS Forum members in idemnity, etc.