Do LCD panels need to be grounded?

[wolvenmoon]

So, here's my current non-tablet but monitor related project:
http://wolvenmoon.deviantart.com/art/Geekgasmic-monitor-1-173118893?q=sort%3Atime+gallery%3Awolvenmoon&qo=1

http://wolvenmoon.deviantart.com/art/Geekgasmic-monitor-2-173119883?q=sort%3Atime+gallery%3Awolvenmoon&qo=0

My issue is that I noticed there is a ground cable on the plugin, and that ground cable goes directly to the mains ground. I do not know if the ground cable goes to the all metal casing that was inside the plastic housing, or if it went to the LCD monitor's metal case, which was also inside the plastic housing. Regardless it was away from human fingers.

The hot glue was coming apart and I planned on epoxying it anyway, but I had a sudden pause because the hot glue made a crackling noise: "Wait, that's grounded to my mains line." The realization slowly dawned on me. "This could kill someone if it's not right, and they wouldn't even have to touch the back of the monitor or pee on it or anything!"

So, my question to all of you is: Do LCD panels need to be grounded to the mains line, or is it safe to assume that this monitor ( previously a dell screen ) would be fine if I clipped this ground off?

Since this monitor IS overheating ( I found the spot that's getting over 65C ), is there any advice to cooling it when I want to re-encase it?

Thanks!

P.S., pardon all the warnings in the deviantart submission. I really didn't want a non-electronics-savvy artist trying to pry open an LCD ( or even worse, a CRT! You never know... ) and run it like this.

[bernard]

I like the humor! I laughed!  

Welcome wolvensun --Oops, I mean wolvenmoon.  

You seem to already have some good electronic knowledge (well to non-electronicians). I am not an electronic guy but I do like these little silicon beasts.

Hot Glue is -- not good for overheating situations obviously(!)

For the cooling, ...well...  you have been doing PC modding -- if there is an area where there is cooling involved, its PC modding! You even got to the point of getting your hands onto an expensive "laser" temp meter. So just put one of those super-duper-ultra-quiet-noctuaPaps-fan (that is probably around in your room?) to blow the heat out, or stick a huge CPU heat sink on it (another part lying in the room in a corner and screaming to do something else than stupidly collect dust). I would say try without a fan to see if it's enough (zero-noise), then add the fan if not enough.   But overheating like that is .. not normal and unless you really cool it down (like shooting "freeze spray can" on the chip continuously) something is obviously dying or not right.

BTW, have you looked for "cold" solders (bad soldering)? Carefully inspect all the board pads and move the parts -- (especially through-holes ones). A bad solder could be the cause of overheating.

If you could post the picture of the spot that you think is the source of overheating -- which board is it?  


Another option (depending where the fault piece is) would be to replace half of the circuitry by a monitor kit/LVDS controller. Essentially only keep the LCD Panel Component (and backlight).  This type of operation is something people do everyday here. (well, not exactly everyday, but still, quite often).


 

[wolvenmoon]

I didn't suspect it was going to be the entire panel heating up to a point it mattered, else I would have used heavier stuff the entire way through!

I've never gotten to a point I designed custom cases / etc, I ran right up to it but in the end could not get a work area where I could work with anything fume-y. Basically I have to work in the room with all the computer parts in it!

I'll get pictures of the board and point out what parts are overheating soon. There are two in particular on it, before I looked just now I assumed they were the CCFL inverters, the 'high voltage' labels on the PCB nearby make me certain of it.

Other parts of it are where they have passive erm...voltage converters... ( I'm really not an electrician, I just have a modding hobby and did like...one breadboard experiment ). They're the little three lead things that screw into heatsinks and convert voltage passively.


This monitor was having an issue with what appeared to be scan lines forming on it, like you would get in an old CRT with a bad signal. It's a bit too old to be worth any $$$ now, but it is fun to try to fix.


My biggest concern is still that ground wire and what kind of risk it poses. I know enough to know that having it contact the LCD metal case itself is either a requirement or a major hazard, so...

[bernard]

That "ground" line you are talking about -- I am not so sure I follow which one you are talking about.  Often the "frame" grounds are hooked everywhere which is different from the "signal" ground and sometimes isolated from the ground pin from the power supply or AC power plug.

The parts with the 3 pins hooked to metal plates with big bolts (often the TO220 package ) could be a lot of things but they often involve "quickly switching power" in one form or the other (thus generating heat) and probably, like you said, involved in regulating voltage (i.e. converting). These parts in a LCD Monitor are typically on the power supply (but can be in the inverter board). It is most likely not on the LCD Panel component circuitry. That means you could get away with a LVDS monitor kit. 

Nonetheless, if you do not want to spend any $$ on this then, ok, we can see what we can do.

[candyjob34]

Oh, I never thought there is a need for LCD panels to be grounded. I haven't done anything on my LCD panel and so far it is working fine. I have to look further on what you are saying because it might really have an effect.

[bernard]

Anything electronic is better grounded as a general rule   ...but can very often work without being so.   Like better static protection and less RF noise for example. Mind you, a real electronic guy would explain (and understand) this way better than me.