LG 50PX4R-ZB stuck in standby mode

[tw2005]

Re: LG 50PX4R-ZB stuck in standby mode

I think 130ohms across Vs -gnd on the Ysus says it all.

No one can give you an iron clad guarantee that's all that's wrong with this old TV.

replacing ysus & zsus together is recommended I believe along with testing the buffer boards for shorts and shorted SMD fets.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

The force starting procedure is only used to get the power supply to fire up; not to get the TV to work. By force starting it, you can see if the voltages Vs, Va etc come up.

Ok..... I just thought that by force starting it the TV would come on

Wishfull thinking !! lots too learn !!

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

I think 130ohms across Vs -gnd on the Ysus says it all.

No one can give you an iron clad guarantee that's all that's wrong with this old TV.

replacing ysus & zsus together is recommended I believe along with testing the buffer boards for shorts and shorted SMD fets.

Thanks .... so 130 ohm across Vs-GND on the YSUS is not normal ??

But at the moment I do not have the YSUS and ZSUS board connected and when I power up it still does the same fault ?? There does not seem to be 5v coming back from the Power Supply, No voltage on Vs BUT when the remote is pressed it does click and RL ON produces 5 v for about 3 seconds ??

[tw2005]

Re: LG 50PX4R-ZB stuck in standby mode

to be honest,I do not have fond memories of these IPM jobs, did 3 and all had ipm failure, either ysus, zsus or both. I don't think you can get these to power up with the sustains isolated or at least with the ysus disconnected.
130ohms I'm saying is bad. The LG manuals are crap.

sorry I really don't think these are worth the trouble but if this is important to you then by all means go for it , I expect the boards won't be cheap.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

to be honest,I do not have fond memories of these IPM jobs, did 3 and all had ipm failure, either ysus, zsus or both. I don't think you can get these to power up with the sustains isolated or at least with the ysus disconnected.
130ohms I'm saying is bad. The LG manuals are crap.

sorry I really don't think these are worth the trouble but if this is important to you then by all means go for it , I expect the boards won't be cheap.

I did my first TV really easy.... it was a Samsung 42" and it was a simple capacitor. At the time I didn't know anything about the different makes so that's why I got the LG50PX4R
I will never ever buy an LG to repair again !!! The only reason I am trying to get it sorted is because I already bought a new main board which set me back about £70 the TV was £40 so £110 all in. I am trying to sell the main board but no luck yet !!

Yes the YSUS board is not cheap the cheapest I have seen so far is £80 ... if it wasn't for already buying the main board I would of got it !!

Its good to know that about the YSUS .... If its not connected it wont power up any way ???

YSUS board it is then !!!!! if I can get one cheap enough !!!!

Thanks

[tw2005]

Re: LG 50PX4R-ZB stuck in standby mode

I did my first TV really easy.... it was a Samsung 42" and it was a simple capacitor. At the time I didn't know anything about the different makes so that's why I got the LG50PX4R
I will never ever buy an LG to repair again !!! The only reason I am trying to get it sorted is because I already bought a new main board which set me back about £70 the TV was £40 so £110 all in. I am trying to sell the main board but no luck yet !!

Yes the YSUS board is not cheap the cheapest I have seen so far is £80 ... if it wasn't for already buying the main board I would of got it !!

Its good to know that about the YSUS .... If its not connected it wont power up any way ???

YSUS board it is then !!!!! if I can get one cheap enough !!!!

Thanks

mate, we've all burnt ourselves on a "easy fix" sometimes you have to cut your losses or hang on in hope something cheap comes along to justify
going further. Doing just the ysus could be risky, zsus could follow soon after or also be dead.

Most of these are probably dead by now and few would be chasing mainboards I guess or even worry about putting $$ into it.

I did board repair and it was a nightmare, getting used IPM parts from china when they advertise new, blowing up brand new modules on another etc.

They have good sound but the picture was average but I am comparing to a panasonic which are excellent.

Before I buy anything dead I try to get an idea of the fault, research for common failures and solutions and check parts availability and prices.

No point getting a "bargain" only to find the parts are unobtainable or so expensive that you could get a working TV for less.

Apart from that it's fun really.

By all means, keep plugging away but I can't help any more except the IPMs fail and the TV goes into protection.

[dkneyle]

Re: LG 50PX4R-ZB stuck in standby mode

Did Suferbum here in Oz ever get that LG plasma TV going? Got a similiar model with similar symptoms (but I can get the power supply to fire up when I remove the Y-Sus supply). I'm planning on substituting a replacement Y-Sus board. But very interested to know the outcome of this saga.

Like him, I'm having fun learning about flat screen TV repairs. I too got sucked in with a couple of easy fixes. I was convinced when I bought this one for $50 that it would be the power supply capacitors. Wrong.

[tw2005]

Re: LG 50PX4R-ZB stuck in standby mode

Did Suferbum here in Oz ever get that LG plasma TV going? Got a similiar model with similar symptoms (but I can get the power supply to fire up when I remove the Y-Sus supply). I'm planning on substituting a replacement Y-Sus board. But very interested to know the outcome of this saga.

Like him, I'm having fun learning about flat screen TV repairs. I too got sucked in with a couple of easy fixes. I was convinced when I bought this one for $50 that it would be the power supply capacitors. Wrong.

Easy to get sucked in by that but when I was doing this it's good practice to search the model for common symptoms/failures. Then research part availability and cost and then decide if it's a worthwhile project.

One of the benefits of panasonics are the blink codes, parts availability, quality of the product, fantastic manuals and resale.

The exception to this are A board issues as ours are fairly unique so getting one from an O'seas model is Nil.

Lot of info in badcaps. Other ways of getting info is searching similar O'seas models. Sometimes dropping the suffix on the model number or better still search panel sustain boards or the panel model in Shopjimmy and reverse search that way.

[dkneyle]

Re: LG 50PX4R-ZB stuck in standby mode

(I like to fill in the story to help others that come along later.) So, I changed the Y-Sus board over. I also found that two 10 ohm resistors on the Z-Sus board had gone open circuit and they were replaced. (Tks tw2005 for that hint.) The plasma fired up all OK. After about 10 minutes I noticed a horizontal black line towards the bottom of the screen. I don't think it was there when I first got the TV going? I did take out the y-driver boards to check for shorts, so I'm hoping it's just a cable not pushed home, or some dust. I will report back! The IPMs seem to be running warm but not hot. The voltages are spot on - I didn't need to reset them.

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

Did Suferbum here in Oz ever get that LG plasma TV going? Got a similiar model with similar symptoms (but I can get the power supply to fire up when I remove the Y-Sus supply). I'm planning on substituting a replacement Y-Sus board. But very interested to know the outcome of this saga.

Like him, I'm having fun learning about flat screen TV repairs. I too got sucked in with a couple of easy fixes. I was convinced when I bought this one for $50 that it would be the power supply capacitors. Wrong.

Nah, never got it working .... ive still got the thing and today i had to put it back together coz the missus woz nagging like mad .
I gave up in the end...as soon as i spent £70 on a y-sus board and it was the same i just didnt want to spend anymore !!!
Im gonna sell it as spares repairs inc the spare y sus board Unless anyone got any last ideas LOL !!

[surferbum]

Re: LG 50PX4R-ZB stuck in standby mode

(I like to fill in the story to help others that come along later.) So, I changed the Y-Sus board over. I also found that two 10 ohm resistors on the Z-Sus board had gone open circuit and they were replaced. (Tks tw2005 for that hint.) The plasma fired up all OK. After about 10 minutes I noticed a horizontal black line towards the bottom of the screen. I don't think it was there when I first got the TV going? I did take out the y-driver boards to check for shorts, so I'm hoping it's just a cable not pushed home, or some dust. I will report back! The IPMs seem to be running warm but not hot. The voltages are spot on - I didn't need to reset them.

How did you find that resistors had gone open circuit ??

[dkneyle]

Re: LG 50PX4R-ZB stuck in standby mode

I was given the hint about those resistors by someone here on the Forum that lives in Australia and had worked on a similar set. They phyically looked OK but were open circuit. They are on the Z-Sus board, down near a bunch of electros on the bottom lefthand side. They are actually in parallel (must do that to get the power wattage up). The code on them reads "100" which translates to 10 ohms. R90 and R901 from memory. I'm not sure of the symptoms they create because I changed them over at the same time as the Y-Sus board. Maybe as one last check before you give up you should check those out? Redaing your posts though, I find it difficult to believe that it isn't the power supply board. I mean, you say you removed the supply to the Y-Sus (and Z-Sus board supply daisychains off that one) so I can't understand why the set would continue to behave in the same way unless it is actually the power supply? I understand at some point you have to cut your losses. I have a spare power supply but it probabaly works out to be uneconomical if I have to post from Oz.