LG 50pb690V Doesn't Turn on!

[reessi]

When plugged in, red power led comes on. After pressing power button led goes out and after a few minutes PSU heatsinks get very hot.

Voltages tested on PSU when turned on with button, outputs to main board are present but none to Y Sus! PSU can be heard turning on and off and voltages to main board do exactly that but not to Y SUS.

Tested PSU on bench and forced on with resistor, now all voltages including YSUS ones are all present.

Can it be bad YSUS or no turn on signal from main board?

Any ideas what to check on YSUS. I have the LG service manual.

Cheers.

[Hamie]

Re: LG 50pb690V Doesn't Turn on!

So you get -vy voltage?

[amirabueno]

Re: LG 50pb690V Doesn't Turn on!

You check the power voltage 12V /5v/3.3V

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Made one mistake in first post, the output from PSU is one cable to ZSUS then thats connected to YSUS.

Another to Main board.

All the labeled voltages turn on when the PSU is out of the set and forced on with a resistor.

The voltages to the Z SUS connector do not come on when in the set, even with that cable un hooked or cable from that to Z SUS is un hooked, makes no difference.

On ZSUS connector is VS -> 205, VA - 55, M5 > 5v.

Voltages to main board turn on and off every few seconds, regardless of YSUS cable connected or not or Z SUS Cable connected.

Mainboard cable has 5.2v and 17V all other pins are:

Auto GND - Whats this?

M_On - Whats this?

17V_Det,

AC_ON - (this turns all outputs on when connected to GND with Resistor),

RL_ON - Whats this?

VS_On - I presumed this was to turn on VS and maybe VA but I havn't tried as AC_ON does this anyway so why is this there?

VS_DET.

Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

Have you tried running the test patterns if you can on this set
can you upload the service manual if too large may have to zip the file etc

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Ok, tested again today, I made a mistake in my post, with the ZSUS dis-connected VS and VA come back so I think we can be sure its the ZSUS. The YSUS is connected to the ZSUS and makes no difference if connected or not so I'm sure the fault is on the ZSUS as this when connected alone makes the VS and VA dis-appear.

Any ideas what I can check on the board. Theres another thread on this forum but I already checked what he found faulty and mine seam to be good.

Cheers.

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Hi, what is the purpose of the test patterns? If there is no screen output, sorry for my ignorance and how do you do that. I think it was mentioned in another thread on this forum as well.

Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

whats the zsus board number used in this set? please remember we dont have the board in front of us so we are going from what information you provide us so some good clear pictures maybe be helpfull

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

Hi, what is the purpose of the test patterns? If there is no screen output, sorry for my ignorance and how do you do that. I think it was mentioned in another thread on this forum as well.

Cheers.

well if the mainboard was bad sometimes the test patterns will run ok so rules a lot of boards out too but as you say you think its a zsus fault now so we can check that first i guess (i havnt worked on many plasmas as still learning) but more experienced members will advise im sure

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Well testing the ZSUS now, every single cap tests short! They're all on the same line so need to figure out if its a cap or something else on the line!

Any good ideas on how to find it without unsoldering everything? No visable damage, what about connecting a low voltage to see what heats up, I've seem alot of people do this on phones!


Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

pictures will certainly help us one good one from top and one good one of the bottom of the zsus so we can see where the traces go to etc.
A lot of other members maynot/wont help/advise when theres no pictures etc

[budm]

Re: LG 50pb690V Doesn't Turn on!

"Well testing the ZSUS now, every single cap tests short!" What are the resistance readings, Ohms, K Ohms, M Ohms?

[reessi]

Re: LG 50pb690V Doesn't Turn on!

I've found the shorts on 4 transistors!

2 x GT30F132
2 x GT30F133

They are on ebay but it would be good if I could get equivalents off RS Electronics. I couldn't find the datasheets.

If anyone knows equivalents of where to find the datasheets, I tried google!

Cheers.

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Its actually a pound cheaper for me to buy the whole board of ebay:

http://www.ebay.co.uk/itm/LG-50PB660...sAAOSwE0JY~x1U

Its listed for a different model tv but this no. matches -> EAX65335001

but this one does not:

EBR77258501 the 8 is a 6 on my board, do think they are the same?

Seams better to replace whole board as I do not know if any further faults on mine!

Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

im think the eax number is just the blank pcb its the ebr number i think you have to match due to different parts fitted etc
the other trouble is with ebay IGBT Transistors there are fakes around so if you can get some from rs etc use them if needed they have live chat which is helpfull as saves ringing them

[reessi]

Re: LG 50pb690V Doesn't Turn on!

So it may not be compatible?

Unless anyone else knows then I'll probably buy the transistors off ebay then. Or RS if anyone knows equivalents.

Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

So it may not be compatible?

Unless anyone else knows then I'll probably buy the transistors off ebay then. Or RS if anyone knows equivalents.

Cheers.

May not be wait for other members input as they may know better also live chat rs and ask about equivalent for the igbts

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Actually after looking through ebay listings they seam to be interchangable the EBR no. or at least for the tv (50PB660V) that I saw the ZSUS for at £12! My EBR no. was listed on several for that TV.

Anyone else shed light on this no.s meaning?

Cheers.

[vinceroger69]

Re: LG 50pb690V Doesn't Turn on!

its a good price so nothing to loose i guess as may even have the parts you need on it also once boards are side by side you can check for any diffrences if big diffrences can always re sell on

[reessi]

Re: LG 50pb690V Doesn't Turn on!

Well I've ordered it and like you say probably has the same transistors on it. The photo of the top looks identical.

I'll report back on sat if it all works or not.

Cheers for helping.