Mulja tv repair portal

Equipment Repairs => PLASMA TV forum => Topic started by: tfix on May 16, 2012,21:38:20

Title: LG 42PX3RVC
Post by: tfix on May 16, 2012,21:38:20

Hello there
Well this is my first post on this site!

 I have a problem witht he above set, it has the Sanken 1H251WI (3501V00220A) PSU, LG p/n 6709V00010A.
The set was intermittently turning off, and it is now permantly off - so at least we have a proper fault to diagnose.
I can't find a schematic for the board, so am stuck to do much more than the basics.  There is not even stby 5V present. There is DC being output from the mains side to the cold side, but tracking why it "dissappears" is a mission.
Does anyone have any info on these boards?  (Tony I sent you an e-mail also)

Cheers
Ian

Title: Re: LG 42PX3RVC
Post by: tv tony on May 17, 2012,02:42:27

hiya, just got it now, circuits for the psu on most plasmas is scant, i will go on the lg site when i get to work to see if there are any stock faults but dont hold your breath, regards, tony

Title: Re: LG 42PX3RVC
Post by: t1412 on May 17, 2012,11:38:51

hi ian, just sent you the manual in your email address file was to big to put on here, all the best

regards
shaun 

Title: Re: LG 42PX3RVC
Post by: zica on May 17, 2012,13:47:44

I had the same problem with my set.
Change capacitor C601 and C603.
Both 1000uF 10V

Title: Re: LG 42PX3RVC
Post by: tfix on May 18, 2012,00:04:14

Brilliant!
Thanks Zica - it's all go now, will soak test in case other caps have ESR also...
BTW, this TV starts off with about  a quarter of the screen showing black bled in horizontally from the right, and then the black washes out to normal picture towards the right.  The pixels start up to green individually  and then go normal.
I think I'll check the plasma HT supplies first.
Anyone seen this before?

Cheers
Ian

Title: Re: LG 42PX3RVC
Post by: zica on May 18, 2012,10:45:37

I'm glad you got it up and running  :thumbup:
Low ESR caps is a must. You should also go up to atleast 16V.
 
The problem you have now, could also be more bad caps.
The logic controlboard is also suspect. It's placed under mainboard.
There are a factoryfault on this sets, that LG call "Mal-discharge". It appears
like red or green dots on the screen.
LG has relesed a kit for this problem. It includes Y + Z-sustain board and logic control board.
The kit: 6871VSNB03E. You can find it on E-bay
http://www.ebay.com/itm/LG-V7-6871VSNB03E-6871QYH036D-6871QYH036C-6871QYH036B-6871QYH036A-6871QZH041A-/270874209719?pt=UK_Sound_Vision_Other&hash=item3f115c6db7#ht_3134wt_754 (http://www.ebay.com/itm/LG-V7-6871VSNB03E-6871QYH036D-6871QYH036C-6871QYH036B-6871QYH036A-6871QZH041A-/270874209719?pt=UK_Sound_Vision_Other&hash=item3f115c6db7#ht_3134wt_754)

Title: Re: LG 42PX3RVC
Post by: tfix on May 23, 2012,02:59:14

Cheers Zica, yes we used low ESR caps, will make an ESR tester for larger value caps too I think.

Interesting stuff around the mal-discharge also, however once it's running it's perfect and I don't think my customer wants to spend any more on it.

Ian