[trdracing5]

I have a 37" LG LCD (model 37LC2d) that has been diagnosed as needing a new power supply. The total to fix was quoted as $400. That is way too much for me to put in to a 2 year old LCD TV.


How hard is it to replace the power supply myself?

 

[MrBobb]

Don't own a LG and never open on up.


However, everything nowadays is modular in fashion and the PSU should be a plug-in thing, just like in a PC. Have u worked inside a PC? U may need some screwdrivers, a cutter/plier, but I doubt anything more.

 

[Vermifuge]



Quote:
Originally Posted by trdracing5 /forum/post/16840682


I have a 37" LG LCD (model 37LC2d) that has been diagnosed as needing a new power supply. The total to fix was quoted as $400. That is way too much for me to put in to a 2 year old LCD TV.


How hard is it to replace the power supply myself?

The power supply is the one piece of hardware in any electronic device that has the potential to kill you. It's not sealed like in a computer and should only be done by a professional.

 

[hammerdwn]

You don't have to worry about hazardous voltages as long as you unplug the Tv before you start the repair. Yes some components will hold a charge even when not plugged in, but the amount of current (if a discharge does happen) is not anywhere near the amount needed to kill a normal person. Simple rule is do not touch the bottom/back of the board where all the exposed solder points are.


All you need is a screw-gun and some common sense. In many ways it's even easier to work on than a computer.

 

[Vermifuge]



Quote:
Originally Posted by hammerdwn /forum/post/16843632


You don't have to worry about hazardous voltages as long as you unplug the Tv before you start the repair. Yes some components will hold a charge even when not plugged in, but the amount of current (if a discharge does happen) is not anywhere near the amount needed to kill a normal person. Simple rule is do not touch the bottom/back of the board where all the exposed solder points are.


All you need is a screw-gun and some common sense. In many ways it's even easier to work on than a computer.

The capacitors in(on) a power supply can hold a lethal charge up to a year. Don't believe me?

http://electronics.howstuffworks.com....htm/printable

Applications
The difference between a capacitor and a battery is that a capacitor can dump its entire charge in a tiny fraction of a second, where a battery would take minutes to completely discharge. That's why the electronic flash on a camera uses a capacitor -- the battery charges up the flash's capacitor over several seconds, and then the capacitor dumps the full charge into the flash tube almost instantly. This can make a large, charged capacitor extremely dangerous -- flash units and TVs have warnings about opening them up for this reason. They contain big capacitors that can, potentially, kill you with the charge they contain.

 

[Extreme_Boky]



Quote:
Originally Posted by trdracing5 /forum/post/16840682


I have a 37" LG LCD (model 37LC2d) that has been diagnosed as needing a new power supply. The total to fix was quoted as $400. That is way too much for me to put in to a 2 year old LCD TV.


How hard is it to replace the power supply myself?

Remove the back plastic cover (2-5 min)

Remove the connectors (probably 3 - 4 connectors; total 20 sec)

Remove the power supply board - usually 4 screws only (1 min)

Install the new power supply board (1 min)

Re-insert connectors (20 sec)

Put the cover back on (2 - 5min)


Total time: 10-15 min.


The capacitors in switched mode power supply do not store lethal charge and will discharge fully almost immediately after you switch the TV off. However, to prevent any possible zaps, hold the power supply PCB at its edges.


Enjoy.


Boky


.... make sure you disconnected the mains (110 / 120 or 220 / 240 V AC) first!

.... power supply replacement at your own risk.

 

[Vermifuge]



Quote:
Originally Posted by Extreme_Boky /forum/post/16844236


Remove the back plastic cover (2-5 min)

Remove the connectors (probably 3 - 4 connectors; total 20 sec)

Remove the power supply board - usually 4 screws only (1 min)

Install the new power supply board (1 min)

Re-insert connectors (20 sec)

Put the cover back on (2 - 5min)


Total time: 10-15 min.


The capacitors in switched mode power supply do not store lethal charge and will discharge fully almost immediately after you switch the TV off. However, to prevent any possible zaps, hold the power supply PCB at its edges.


Enjoy.


Boky

If for any reason the bleeder resisters/circuitry have been damaged trdracing5 could be in for a world of hurt. These newer LCDs have large capacitors in place to help power up the display quickly. That's why you can disable the quick start in some of the newest TVs.


P.S. Thanks for adding ".... power supply replacement at your own risk."

 

[Extreme_Boky]



Quote:
Originally Posted by Vermifuge /forum/post/16844252


If for any reason the bleeder resisters/circuitry have been damaged trdracing5 could be in for a world of hurt. These newer LCDs have large capacitors in place to help power up the display quickly. That's why you can disable the quick start in some of the newest TVs.

yes, that is why I suggested to disconnect the mains first


Boky

 

[MrBobb]



Quote:
Originally Posted by Vermifuge /forum/post/16841615


The power supply is the one piece of hardware in any electronic device that has the potential to kill you. It's not sealed like in a computer and should only be done by a professional.

Are we being a bit melodramatic here?


Sure the ole CRT had like 15,000 volts and needs to be discharged properly, but modern LCD, what voltage are we talking about?


OK, I agree, don't do it in the bathtub.

 

[Extreme_Boky]

The most dangerous is approximately 400V DC used by switched mode power supply as DC bus (if your mains voltage is 240V AC).. This has potential to kill you…

Tuner: +5 and + 15 (and possibly -15) V DC

Pixel driver board: +15 V DC

CCFL driver board +60 and -60 (this is 120V DC…. can give you shock...)

CCFL high tension / high frequency AC can not do much at all.... but to give you very mild local burns ... and a smell of a BBQ...


Of course, all the above is with the TV ON…., so avoid SMPS and Inverter boards….



Boky

 

[hammerdwn]

I've never been zapped from any lcd power supply after the power is off. I have seen arcing, burning, smoke with them plugged in. Stay away from the inverter connectors to the panel when power is applied!


I have been zapped more times than I can count by plasma and crt based boards after they are removed from the Tv. It will make your fingers numb for a few seconds, that's it. I've had some zaps from live circuits and those can run up your arm and into your chest, but never had to seek medical help for it.

 

[gtaylor0]

OMG One has to wonder is this will be your final post.

 

[MrBobb]

Hey once u get zapped a few times, u may start liking it.

 

[trdracing5]

Im still trying to decide whether I want to do this myself and risk death!!!!

The part itself is around $125.

That means the repairman is making $275.

Does that sound reasonable? It doesn't to me.

How much should this repair actually cost me????

 

[hammerdwn]

Labor is $250-$300 these days

 

[trdracing5]

I just couldn't justify paying that much to fix the tv so I purchased the part and fixed it myself. Works fine and was actually pretty easy to do. No problems at all.

 

[Extreme_Boky]



Quote:
Originally Posted by trdracing5 /forum/post/17006888


I just couldn't justify paying that much to fix the tv so I purchased the part and fixed it myself. Works fine and was actually pretty easy to do. No problems at all.

Great news!!! Well done !!!


Boky

 

[bill4903485]

Just use caution, a little bit of common sense, and you should be fairly fine. Either hold the board on the edges or simply discharge the caps. Part of the scare tactics are those not wanting consumers to hone in on their action. Obviously some of the concern is genuine.

 

[See The Light]

How to remove the pins ? ? ? ?


I'm attempting to remove the power supply board from my Sanyo DP42040.


The pin to the AC power cord came off easily.


But the pin for the cable, that goes to the circuit board, does not want to come off. There is a "flange" to press, which I do fully press, and then I pull out,,,, but nothing.


The other pin, that goes to the screen?, does not have a "flange". Is there something I need to do, other than just pulling on that pin ? ? ?

 

[MrBobb]

Post a close-up pix.