Got a p50u50 from Adorama in early February, and I'd say I've just crossed the 100 hour mark (everything set to 50 - first plasma and all). Everything looked and SOUNDED perfect until this week when, after plugging in my brand-new blu-ray player (also a Panasonic - a bdt-220) my beloved bargain plasma began to hum. The problem gets worse when the picture gets lighter. From reading this thread I see that others have had this problem, so I apologize for bringing this up again, but I have a slightly different take on the problem. I live in a relatively old apartment block, I rent, and let's just say I have reason to suspect the wiring might not be up to code
. I know in some cases this is caused by hysteretic energy loss in inductor/transformer coils: this kind of energy loss is dependent both on the frequency and the rate of change of the frequency of the voltage supplied. Straight high frequency is bad, but we don't have to worry about it because mains electricity is more or less frequency-regulated, and if it went off enough to cause a problem, you'd notice a lot more than transformer hum. What I do have to worry about are fluctuations in frequency, say from capacitance/inductance somewhere in the circuit, either from some appliance of mine or my neighbors' or parasitism from faulty wiring (although I suppose if you did a Fourier decomposition of the wave-packet this would be equivalent to adding in higher-frequency harmonic modes, but same difference). I happen to have bought two zero surge surge-protectors before this happened. These would filter out the frequency modulation on the line and thus in theory fix the problem. My concern comes from reading back a few posts, where someone says that he opened up his tv and found that the transformers had cracked and that this was what was causing the hum. I am worried that the transformers may have cracked and that this fix is too late.
I'll let you guys know my results, but I'm not optimistic.
If the transformers have cracked, will Panasonic be able to replace the transformers without replacing the screen? I don't want to go through aging a screen all over again (I do it naturally, by boobing out, so it takes more time than it should).