Vizio p50hdm i get sound but no picture, wahat part do i order?

Check and replace damaged component/s at it main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" or "Magazine" will make surf easy. Surf the site with patience. Pull up older posts. Do asearch by type in the brand name of your device at its search box.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis.

Check you voltages before just swapping out boards. Although a YSUS is common for no picture, so is your upper and lower Y Buffer boards or the panel itself. Check youe -VSC voltage. Does it look like it is being loaded down? If so then your YSUS is not the problem. You can run the set with just the upper or lower Y Buffer boards untill the load is gone. That will let you know wich board to replace.

The z-sustain board is bad. One of the the heat sinks on the board is cool to the touch. These had LG circuit boards and the number on the sticker, on the board, was a good LG part number. The part numbers were 6871QZH044A.

Do a search on the internet with Google, Yahoo, or Ebay with this part number. The board unplugs and the new one plugs back up. Not an advanced technical repair. Unplug the set and take the back off and match the picture on Ebay with the one in your set. And especially match the part numer.

P50HDM, loud pop then no pic...

It's either the backlight lamp or backlight inverter is busted due to a power failure or fluctuation. Here's how to determine which is which:

1. Grab a flashlight.
   
2. Turn on the TV.
3. Shine the flashlight onto the screen.
4. If you cannot see any display even a faint one, the backlight inverter is dead, else the backlight lamps are busted.
5. Replace which ever is the culprit.

this is most likely the sustainer board(s) problem. Replacing the sustainer boards should correct this problem for you. you can get the parts at vancebaldwin.com

replace the sustainer boards should correct this problem. New sustainer boards may cause red and green pixilation. If this happen, replace control board and TV is as good as new.

Ok first i need to know is the TV showing anything at all or just a blank screen ? And if you know what the Y or Z board is who is the manufactured of the plasma panel is ?

Hey guess what?! After Costco shafted me good, told me to get lost, and slammed the concierge phone down, I called Vizio. THIS TV HAS A LIFETIME WARRANTY ON IT NOW!! They will fix/replace it at their expense! After a 5 minute call to their customer service they arranged the repair order. Vizio knows that this set is a lemon and they are actually owning up to it. The gentleman told me that this set now carries a Lifetime warranty on parts (to exclude a shattered screen of course) and labor! The repairman is going to come this way in the next week or so and I'll update you on what he says. So to all out there with problems on this set: CALL VIZIO AND GET READY FOR A BREATH OF FRESH AIR!

PLEASE READ THIS. I bought my P50HDM back in December 2005 at Costco. The 'Pop of death' hit last night. I called Vizio today and the tech person told me the warranty had expired. Nothing they could do except set up an appointment for a service call for which I would be responsible. When searching the web today I saw a post in which someone reported that they had also bought there P50 at Costco and that after calling the Costco concierge program @ 1-866-861-0450, they found out their TV was still in warranty even though it was also several years old. I called Costco, excellent people to deal with, and told them my problem. They entered Model# and Serial# into their system and informed me my set was still under warranty. From here the Costco technician calls Vizio direct and puts you on a three way call. In my case it took 25 minutes of waiting, I did not mind, and the Costco tech told she had to go through three levels of Vizio techs to get the correct person. I spoke directly with the Vizio representative as the Costco tech listened in. The Vizio tech apologized and said "YES, THIS IS A KNOWN PROBLEM" with th P50 and it is still under warranty and they will repair it for FREE. This is for real. If you bought through Costco call the above number and let them handle the Vizio people. If not, call Vizio and insist on speaking with a supervisor until they admit there is a problem with the P50 and they agree to repair it. They are apparently taught to reply that your warranty has expired, but when this amount of money is on the line you should push until they agree to fix at their cost. Please do not let Vizio tell you the warranty has expired bit, they have to fix it because it is a defective design. Call and do not let up, you will save a small fortune.