I have a 42" philips plasma with 8 red blinks

Yes,u know how to solder right?Just use a fillip screw driver,u should able to opne it the back cover all the holes with screws.Here are some website u can buy parts for it.Tv Repair World.com,Shopjimmy.com,Ebay.com or Partstore.com.It a whole big plastic sheet,open all fillips screws it with a fillip screw driver,all holes with
screws ok.

hello, amigo if the all the caps are godd then you have to replace the power supply board. don't try to fix it this is not an easy task. you are looking at almost $200.00 with tax an shipping. just go to google and type your tv model # and ask for the power supply board or just look for the part# on the board itself. good luck

sounds like your tv in shut down mode why lamp needs 2 be replaced nominal cost 120 200$

The mainboard is damaged.

How many times is the led flashing or is it flashing???

These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices. http://electronicshelponline.blogspot.com/
Blinking codes details of many popular brand TVs are given. Surf the site with patience. If blinks continue without any pause, the main board is faulty.
Counting of number of blinks to Philips TVs is entirely different to that of other brand TVs. It is not a direct count procedure. The site have details about how to count the number of LED blinks [Fault Codes] to Philips brand TVs are given; along with details of the faulty circuit location.
Search the site by type in the "brand name" to your device, in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.

Problem is a bad audio IC esp if your are reciving 11 blink code
if it is a 5 blink code replace Crystal 1h00 On Ssb new part number is 24225430 1397

The probleis with one of the maina boards and trouble shooting would have to be done to see which board is bad.

did u cheak the input cables does it do it on dvd input as well as others ?

U better have it checked by a qaulified tech