About 2 weeks ago my dell 42" plasma started

change your tv main board, your tv board was broken

I would look for a power supply from discount-merchant.com or shopjimmy.com if you can't find then repair the ps, look for bad caps bulging or open and ousing out.

Hello, Ur power supply board is dead, u know basic electronics’ and soldering? Most of the times, the power suppply board just have dead leakages gases capacitors.These capacitors alway bulges up on it top,or puff up on it top.Replaced these gases leakages capacitors will get ur tv power stable,and work again.Or tries websites like Shopjimmy.com,Ebay.com to buy a whole rerfurbish power supply board for the replacement.

Yes,make a noise to power up and turn off power only.But not in 30mins,with 5 or 6 mins

Sounds like, and no it usually take a professional to replace. Trust me there tiny parts in there. Some tv's takes speacial tools to take apart without damage them.

Sounds like power supply check you voltages. Search google for a service manual

http://rns-systems.com/

needs new panel and a updated power board. firmware must be 51-7 (current)

i used my plasma 42'' model MT-42PM11 about 3yrs ago i found out after a week that there is black middle bar on the screen how to solve this issue.

Had the same problem.  Was quoted $800 to fix.  Searched the internet for 6 months and found this thread on avforums.com

 

http://www.avforums.com/forums/showthread.php?t=462873&highlight=black+line+on+plasma&page=4

 

Read through all the posts.  Very simple fix, but you have to have some mechanical inclinations or you can cause more problems than you started with.  I was up to 5 of the black lines, but decided to attempt the soldering these guys did and fixed it all for the cost of a soldering iron!  Even if you decide not to attempt it, it gives you somewhere to start to tell a technician.

This exact same problem happened to me 2 weeks ago on my Pioneer PDP-4330HD, and it did indeed turn out to be the power supply. The good news is, you can get it fixed for free, because Pioneer actually recalled the power supply in this plasma and others a couple of years ago.

Here is a link to the announcement on their website concerning the recall. They say that they will do a free in home replacement of your power supply, but when I called the local pioneer repair place, I was told I would have to wait three weeks for an in-home appointment. I ended up taking it in myself, and it was fixed for free 2 days later. Now it works perfectly.

Here's the number to call Pioneer in case the link goes down:

1-800-421-1404