My high def component 1 and 2 just blink on and

Bulged Cap issue is to do with power sub-system and generally more in the LCD/LED tv not Plasma.

Begin from
42 Class 41 6 Diagonal Plasma HDTV with EZ Sync

Do you get blinking codes ?
Panasonic TH 42PX70 St By Light Flashes 10 Times
Not sure if it is the thermal fuse issue in your case though.
See How to Repair PANASONIC Plasma TV with Blinking LED TH 42PZ77U TH 42PZ700U

Check and replace the damaged component/s at its main board. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/

Check and make sure your high def cables didn't come unhooked

The power supply most likely is on the edge of failing. It may or may not work. This is because some components are on the edge of proper specs. The power supply module is serviced by replacement. It is not supported at the component level.

Sometimes other modules in the set could have caused the power supply to have some problems. The other modules should be properly verified. You would not be able to do this yourself unless you had the proper setup, training, and tools for this type of service work.

Just a couple of things to try:
You say you tried another cable box and a roku. Are you using the same cables? Are you using hdmi, component or coax cables? Could be a bad wire. True high def tv 1080 requires an hdmi cable for the best picture. The next best choice is the component cable. This is a triple cable with red, green, & blue and provides 720 resolution. The least quality is the coax wire which will only provide low def standard quality picture. Sometimes people hook up 1, 2, or all 3 of these choices not knowing what it all means. If thats the case with your tv it may just be a matter of selecting the correct input on your tv with your remote. On your samsung remote there should be a button for input. Try pushing that button and make sure it's set to hdmi or component, whichever your using. If none of this, is it possible the plasma tv itself is defective?

Choose connections on the Panasonic that match those on the player--

Do you have on the player Component outs(blue,green,red and 2 audio which are red and white? This ought to give you the best picture and sound.

Other inputs to the set must match the ones coming from the player--Most owner manuals have a lot of details here.

If the player has 1080 output hook to a similar input on the set.

Some advice here: make the connections between units with both turned off.

try mcmelectronics.com

It could be the mainboard is damaged, but in order to be more specific I need a little bit more details on symptoms.

Your TV plays High Def material through either Input 4 (uses component cables R,G,B) or through Input 5 (Uses DVI cable).
Today most equipment uses HDMI cable for High Def or it may have a component (RGB) output that you can use. The DVI hookup is best, so you need a HDMI to DVI cable or Component Cables (Red, Green, Blue). You need some source that OUTPUTS High def (ex. 1080i) either through HDMI or component cable. You need to either connect the component cable(R,G,B) from the source to the Input 4 on the TV or connect the HDMI to DVI cable from the source to the Input 5.
You need to set the AV source on the TV to AV5 (if you are using the DVI input) or AV4 (if you are using component cables).
If you want to play Highdef source like Blue Ray then you can just connect the output of the blu ray player to your Tv using either the HDMI to DVI cable or component cable (Red, Green, Blue) and set the TV input to AV5 (for HDMI/DVI) or AV4 (for component).
But if you are trying to get Free High Def from an antenna then you will need to have a component that can OUTPUT high def. The $40 converter boxes don't do this - they simply convert the Digital signal to Analog (non high def). What you need is a High Def TUNER that OUTPUTS High Def. I was looking for one for this same reason and ordered the centronics ZAT 502 HD. But it cost about $80. Then I saw that Tivo had an upgrade deal where I could upgrade my existing Series 2 Tivo to Tivo HD for $99. It has a High Def Tuner in it. So I cancelled my order with Centronics and got the Tivo. In any case if you want Over the air HD you will need a High Def Tuner that will OUTPUT 1080.

The only simple fix fix for that may be an "ac boot", otherwise known as "unplugging for 1 minute, the plugging it back in.
Sometimes the internal microprocessor gets scrambled and this *might* help. If not, there is an internal fault which needs attention from qualified personnel.

www.mcveyelectronics.com