LG 50PJ350 dead, relay clicking

[aasnowskate]

I have a LG 50PJ350 that is not working. I looked through some other posts and found similar problems and did some work before posting this.
I found one bad resistor on the Power Supply board. I replaced it and the resistor beside it. They were both 22w 5 ohm.
The problem still was the same. I noticed that the D201 was not lighting on the Main Board. So, I replaced the main board and the problem is still the same. I was getting all the proper voltages to that board from the YSUS board, so I thought it was bad.
Today, I went back through and started unplugging the YSUS and ZSUS from the main board. With the YSUS unplugged and everything else plugged in, there is audio and it doesn't cycle throught the relays like it did before, it stays on.
With the YSUS plugged back in and the buffers unplugged, it goes back into the standby shutdown mode.
I am thinking YSUS now.
Any suggestions to try?
Thanks in advance.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

Did you find the zenith 50pj240 post? Sounds familiar though he's yet to get it going and check out the sustains and buffer boards. There's a training guide I uploaded for your model. The ysus and zsus power are chained which I hate for fault finding.

All I can suggest is to check Ysus,Zsus & buffers and see if anything is shorted. Maybe measure the resistances at the power connectors e.g Vsus etc.

I have a full set of boards for comparison for this one.

The training guide has some good info and checks in it.

Z50PJ240

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

Thanks for the reply. I will check the resistances and get back to you.

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

I can't view the training manual you posted in the Zenith post. Is there another link to it? My computer will not allow it to open.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

It's compressed with winrar. I can find the link for direct download for you, once these get to the size limit I have to use RAR so the forum takes the upload.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

2 free downloads per 24hr

[tom66]

Re: LG 50PJ350 dead, relay clicking

Block diagram may help too


As might alignment details for panels, including PDP50T1 in this set.

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

Thanks for the info. That service manual and block diagram from Tom came up for me. I did the light bulb test on the power supply just to rule that out and it worked fine. It kept the lights on for several minutes.
I also checked the two buffer boards coming off the P212 connector from the YSus. I checked them for shorts and found none. I am thinking it is the YSUS. I don't have a scope to check the YSUS like it says to do in the manual. Is there anything you think I could check with a DMM before ordering the YSUS board?
The least expensive one I can find is $175 on ebay.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

Geez, you're kidding. They must be in high demand.

I'd check Ysus and Zsus in case. Pick a point I guess. measure the resistances on the power connectors on the YSUS and post. I've got my board here, it's getting late so I'll hang on otherwise it'll be tomorrow .

Don't know much about these, tried a Samsung with chained boards at component level and gave up. ended up replacing the 3 boards at once.

Did you try Tom's control board test bypassing the main to see if the panel fired up?

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

Am I measuring VS to Ground?

[tw2005]

Re: LG 50PJ350 dead, relay clicking

You sure about the price? I see cheaper and brand new here $70 plus freight from LG! And we're usually the ones that get ripped.

Are there any LG direct parts sites in the US?

I suspect EBR63039801 , EBR63039802, both will work

[tw2005]

Re: LG 50PJ350 dead, relay clicking

Am I measuring VS to Ground?

Start there, it may charge up and change. Just let me know the steady figure and which way you have the probes. Is it a quality meter you have ?

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

I just found the EBR63039801 on Ebay for $96. Where are you looking? I am not sure if the 801 will work or not. I emailed the seller, we will see. I have to go out of the shop for a bit. Let me know if you find anything and where I am looking for the resistances. Thanks for all your help so far TW2005.
I will look a little more for the board.

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

It does charge up at 1400 ohms and change to open with the DMM. When I use an analog meter from Ground black probe to VS red probe I get 10000 ohms steady.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

It does charge up at 1400 ohms and change to open with the DMM. When I use an analog meter from Ground black probe to VS red probe I get 10000 ohms steady.

This is my DMM , old fluke 73 auto range.

Initially 300K, take off and on again, 2.8meg

In diode mode it simply charges starts at 0.4, continues just past 2 and goes OL.

Short Vs and gnd pins and see if the result is similar to mine.

gnd-Va I get 4.1meg, diode similar to Vs 0.4 - 2 then OL, won't repeat unless Va and gnd are shorted to discharge cct.

gnd-15V beeps initially but charges to 0.95, resistance is all over, starts low , k ohms then jumps to 2-300k then lift off and on goes to 2-3meg.

There's a couple of pico fuses, not sure if they're worth checking.

I can see myself looking a bit silly here, if these don't present a dead short somewhere and fail in some other manner.

[tw2005]

Re: LG 50PJ350 dead, relay clicking

LG here in Aust, http://www.electronicmarket.com.au/5...5735_5736.html

freight would kill it but the US being such a huge market I'd expect a similar price and a website that retails these too?

[tw2005]

Re: LG 50PJ350 dead, relay clicking

sears $110 http://www.searspartsdirect.com/part...rt=EBR63039802

[tw2005]

Re: LG 50PJ350 dead, relay clicking

You may like this I found , reclaimed $30 and they state the 9801 board will work and another.

http://www.encompassparts.com/item/8...t_Pcb_Assembly

http://www.encompassparts.com/item/8...vtp_Board_Assy

http://www.encompassparts.com/item/8...1/Ydrvbt_Board

http://www.encompassparts.com/item/8...40301/Zsus_Pcb

Just over a $100 for all if I'm seeing right>

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

Thanks for that TW. I ordered it through the link you sent me. For $30 it is worth getting it and if it doens't work, I will be able to resell it.
Thanks for all the help. I will post my results when I receive the board.

[aasnowskate]

Re: LG 50PJ350 dead, relay clicking

I got the new YSUS. Put it in and got the same result. When I first plugged it in, the YSUS made a different noise like something burnt out. When I unplugg the Ysus, I have audio, in the form of static noise. I don't know what to think.