the popping is terrible I have totally unpluged it from my surround sound system and I am now using my telivision speakers, so far no solution.
After 4 months of dealing with Panasonic customer support and their authorized service centers I finally have an answer to what is causing the popping noise and sporadic sound loss. The Panasonic tech actually called me, which renewed a little faith in the company. He said it is a know issue with a number of these systems. Apparently a circuit board on the amplifier in the subwoofer is faulty.
Now why does the authorized service centers not know this and why does the customer service personal guarantee you there is not a known defect in the product. I can't tell you.
I bought the t900 in november and today was the first time i got the popping problem, and its VERY annoying. You can mute the unit and still hear it. I will see in the am if it is because the unit overheated. I have had the unit on watching dvd's for about 5hrs straight.
To all those having problems with the sc-ht900, I got a really good deal on one, then found out about the overheating. Not wanting this to be a problem I decided to investigate. I popped off the back panel of the sub to find that the fan wasn't actually working. I imagine that it is supposed to kick on when things start getting hot, but my unit was already really hot. The heatsink inside was almost too hot to touch. The fan is 80mm so I took a led case fan and replaced the stock one. The stock one has some non standard screw holes so I had to use some strong adhesive foam tape to hold the new fan in place. Then I ran the wire outside the sub and rigged up a small ac/dc power adapter to power the fan. It took about 30 minutes to do and now my unit runs very cool, and has a cool looking blue glow on the wall coming from the fan to boot. You could just use the stock fan and rig up an adapter to it but I didn't want to cut off the connector in case I needed to take the unit back. For the adapter use something between 7 and 12 volts, lower voltage = quiter fan but less airflow.