Hello,

I could use some assistance..

I got a Panasonic TH-50PX70 Plasma TV, and have burned my digital processor in my tv 3 times now..

The two first time I just thought it was a TV defect and didnt really think about it.. Then I got aware that HDMI is not hotswappable.. So every time I changed my DVI-> HDMI I removed my TVs power before changeing what computer my DVI was connected to.. However I didnt think it was neassasery to power off my PC (since I use my server as HTPC)..

I put the DVI in my server HTPC (running linux, shouldnt matter thou) and started to detect my TV screen, I get a picture on my TV, but theres snow all over and weird colors.. a few seconds later BOTH HDMI ports are dead (blown digital processor on the TV).

I contact Panasonic tech support, and get told they have heard about the problem before, and usally its because the graphic cards output a voltage 3-4v where the HDMI standard is 0,3v.. The problem should not occour if both devices are powered off before changeing any cables..

My server have a Inno3d Nvidia Geforce 7950GT card..

Have anyone got experience in this area, or can recommend a graphic card with a HDMI output that follows the 1.3 HDMI standard according to voltage output so this dosent happens anymore?

Hello,

I could use some assistance..

I got a Panasonic TH-50PX70 Plasma TV, and have burned my digital processor in my tv 3 times now..

The two first time I just thought it was a TV defect and didnt really think about it.. Then I got aware that HDMI is not hotswappable.. So every time I changed my DVI-> HDMI I removed my TVs power before changeing what computer my DVI was connected to.. However I didnt think it was neassasery to power off my PC (since I use my server as HTPC)..

I put the DVI in my server HTPC (running linux, shouldnt matter thou) and started to detect my TV screen, I get a picture on my TV, but theres snow all over and weird colors.. a few seconds later BOTH HDMI ports are dead (blown digital processor on the TV).

I contact Panasonic tech support, and get told they have heard about the problem before, and usally its because the graphic cards output a voltage 3-4v where the HDMI standard is 0,3v.. The problem should not occour if both devices are powered off before changeing any cables..

My server have a Inno3d Nvidia Geforce 7950GT card..

Have anyone got experience in this area, or can recommend a graphic card with a HDMI output that follows the 1.3 HDMI standard according to voltage output so this dosent happens anymore?Boy that sounds fishey. Being an electronics engineer, I know that it is a bad thing to connect a powered device to another that is not powered. This pertains to most CMOS logic. But these "rules" apply to the internal connections in a system, for example trying to run a processor connected to memory chips that are not powered is a no-no. That being said, most interface standards for system to system, such as RS-232C, or USB are DESIGNED to allowed hot connections. I don't know about HDMI but it sounds like Panasonic is passing the buck. I have my HTPC connected to my LG TV over HDMI. It is normal for me to have the TV off while the HTPC is recording OTA content. Or PC off while TV is connected to DirecTV DVR. I usually don't hot swap VGA, PC parallel printer connections, DVI, or HDMI cables. But HDMI cables have been known to fall out of the sockets. I've read tons of posts here about ATI graphics cards losing video requiring a disconnect.
Anyone who knows whether the HDMI standard specifies hot disconnect or not please jump in here. Lastly, many PC interfaces now have transient protection circuits either in their chips are added to the I/O lines. Frying a couple thousand dollar HD TV is a big deal.

I dont hope its a problem having your PC powered on, while the TV is powered off when they are connected.. Because then its ussage is almost completly useless to me..

I thought it was only a problem related to changeing cables while one device is online and another offline.

Yes the problem pisses me off alot.. having to send in my TV 3 times to repair not knowing if I can prevent it by powering both devices off when switching cables.. Dont want to burn it another time.. not sure if my warrenty will even cover it anymore.. (after 2 times already) with another device involved :/

A two quesitions that probably are not relevent but may be:
Do the TV and the PC use the same circuit and therfore ground connection?
Have you tried a different cable?

Panasonic is giving you LOTS of bull. Swapping "external" cables like DVI/HDMI/USB/VGA etc has absolutely no requirement for the systems on either end to be power down before swapping. None. You can connect/disconnect them to your heart's content while the systems are powered on, and you shouldn't have any issues.

Things I'd try.

- Go buy the cheapest TV with an HDMI connector from Worst Buy and try it with your system. If you don't see the problems with this test TV, return it to Worst Buy (I know..I'm bad. But Worst Buy is worse), and return your Panasonic TV as well. If Panasonic gives you grief, tell them you'll sue them for faulty equipment. If they still give you grief, take em to small claims court. When they get the notice, they will settle in a hurry.

- If you DO see the same problems with the test TV, buy a new graphics card and cable from somewhere where you can return them. Test again.

You have something shorting somewhere.

A two quesitions that probably are not relevent but may be:
Do the TV and the PC use the same circuit and therfore ground connection?
Have you tried a different cable?

The TV and PC are attached to the same power socket yes, not sure about the ground connection in that power socket (im from denmark).. Will it be better to split them up using diffrent power sockets?

I'm using a 10m Supra DVI->HDMI cable, no I havent tried another cable, I will order another one to use.. but its supposed to be a high end cable.. cant understand why It would be the problem..

I have a bunch of cables from xbox,ps3,computer,switch laying behind the TV on the floor where my subra cable is as well.. but that shouldnt make so much interference that it could blow my tv's digital processor huh?

Another fun thing, in the products manual (Panasonic TH-50PX70) under HDMI specs it says something like 'Not for use with PC'.. which makes zero sence to me.. Im contacting panasonic support..

I mean if you cant use the TV together with a mediacenter outputting DVI->HDMI 720p signal its completly useless to me..

Another fun thing, in the products manual (Panasonic TH-50PX70) under HDMI specs it says something like 'Not for use with PC'.. which makes zero sence to me.. Im contacting panasonic support..

I mean if you cant use the TV together with a mediacenter outputting DVI->HDMI 720p signal its completly useless to me..My older Sony 36" XBR (4 x 3 CRT display) says the same thing in its manual. Believe me you would not want to use it as a PC monitor to do any work. But it is acceptable for routine tasks like updating software, defragging the hard drive, etc. The media center display at 720p is gorgeous. We use it in a small room. MC letterbox display is equivalent to 32" 16 x 9 display. No HDMI just DVI port. Hope you get you Panasonic issues ironed out. Kapone says it should tolerate hot connect/disconnect. He knows his stuff.

Another fun thing, in the products manual (Panasonic TH-50PX70) under HDMI specs it says something like 'Not for use with PC'.. which makes zero sence to me.. Im contacting panasonic support..

I mean if you cant use the TV together with a mediacenter outputting DVI->HDMI 720p signal its completly useless to me..

That statement is in lots of HDTV manuals especially older ones only says that because their HDMI interface does not support standard PC resolutions. Since the TV has no idea where the signal is cooming from any PC graphics card that can output standard ATSC resoloutions such as 720p or 1080i works fine and all of the graphics cards for the last few years meet these specs. So ignore the statement in the manual.

Well still trying to investigate what the problem might be..
I got the following graphic card:
XFX Nvidia geforce 7950GT 550M dual dvi with hdcp support

Trying to dig up any specs and contacting their support but cant really find the dvi voltage output (if what panasonic says have any truth).

I just hope to avoid the problem by not hotswpping my DVI-> HDMI cables :/

Can anyone confirm the 0.3v as standard HDMI voltage? because I cant find it..