GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

[hazzaman]

Hi Guys,
New to this site

Have been given a (no real brand name) GVA LED LCD TV from my Elderly Parents to try and see if I can repair.

TV model: GVA32UA2
Main board: Unknown for now
LCD Panel: Samsung LTA320AN01

Symptom: TV turns on and after 5-10mins or at times 3 days later the picture will fade from left to right to a black blank screen. Stay black blank for a 1-2 seconds and then go blue stating No signal for 1-2 seconds and again black blank screen for 1-2 seconds. And keep doing this.

I can turn the TV off disconnect it from AC Power overnight and the next day it will work fine all day. For a few more days.

Does this sound like failing Caps? Being a cheap type of TV they are probably cheap and nasty caps?

I am hoping to fix the TV for my Elderly Parents to save them the cost of buying a new TV since they are on the Age Pension. (Will buy them a new one if need be.)

But hoping someone can put me on the right path to what could be the fault.

I will try to open the TV up during the Weekend coming.

Thanks
Hazza

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Anyone able to help a guy from Downunder

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

I was hoping for someone to give us a tip

[tw2005]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

can only throw some guesses but if the Power board is fairly simple you could just recap it in hope. Could be dirty power. Being 5 years old at a guess the life expectancy has been reached for crappy caps.

Other wise mainboard, maybe you could experiment with heat and see if you can induce the fault by heating up one board at a time but if it's spasmodic and then good for days I'd lean towards caps.

you'd think if it was heat and mainboard it would depend on how long it was on and happen every day.

Feel free to post up pictures using go advanced , manage attachments, some of the others who do LCD TVs more may recognise what they see.

Also of the boards inside, it may have the same power board as something else and then you can search the part number for the same symptoms in another TV potentially.

[ReeceyBurger123]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Seems to me like bad connections in the Led strips. Do some research on how to test the Leds and upload some pictures. We need you to help us.

[tw2005]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Seems to me like bad connections in the Led strips. Do some research on how to test the Leds and upload some pictures. We need you to help us.

I took it was running normally, fades and then blue screens with no signal.
Are you thinking it's rebooting due to bad back light or LED strips?

If that's the case then would it not go back to normal viewing without the no signal?

anyway, always interesting the different ideas we come up with

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Will do all the above and get back to you all, Thanks
for the replies Guys.

[budm]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

"Symptom: TV turns on and after 5-10mins or at times 3 days later the picture will fade from left to right to a black blank screen. Stay black blank for a 1-2 seconds and then go blue stating No signal for 1-2 seconds and again black blank screen for 1-2 seconds. And keep doing this." So if you look at the back side of the LCD panel, do you still see the backlights glowing when the front of the LCD panel is black?

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

So if you look at the back side of the LCD panel, do you still see the backlights glowing when the front of the LCD panel is black?

Will try this also, will try to do all the above tomorrow. Will get back soon.

Thanks

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Hi Guys an update

Firstly I noticed that the Main Earth was not actually connected to the
Power Supply, it was just sitting on it. But the Main board was Earthed.

I got the following details

TV model: GVA32UA2
Main board: T.MSD306.9A 10331
LCD Panel: Samsung LTA320AN01
Power Supply: MEGMEET MP116A Rev:1.0
Inverter: Samsung SSI320_4UN01 Rev:1.0

I have attached Pictures also.

I am Getting the following Voltages out of the Power Supply when turned on.

+12v = 11.87v
+5v = 5.06v
+5vPS = 4.46v , (+5vPSON I think could not read details)
+24v = 23.75v

Could not read anything on 5VSB

I tried using a Hand Dryer over both the Power Supply and Main Board and
got no change in Picture. I do not know if I left it long enough, but had it on for 2 seconds every spot.

It has been 3 1/2 days since it played up so , I could not fault find to see if the Backlights are still on when the screen blanks.

Will advise if it does occur. I am hoping that all it was, was a loose earth on the Power Supply, please advise if this could be the cause of it all.

Thanks

Hazza

[tw2005]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

So first thing I notice is it's a Megmeet PSU which seem to get a bad report from plenty in the forums.

Searching MP116A, I've just picked the second thread in my list

https://www.badcaps.net/forum/showth...ghlight=mp116a

Sounds similar problem, there seemed enough follow up reports of success until I read further on with ROHANU then talking inverter?

Typical it's been fine for a few days.

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Searching MP116A, I've just picked the second thread in my list

https://www.badcaps.net/forum/showth...ghlight=mp116a

Typical it's been fine for a few days.

Thanks tw2005 for the reply,

Yes that is what I did also, I googled MP116A Power Supply and got a badcaps thread.

Yes it does seem Typical to work fine when it is the weekend and you have time to pull the TV apart to fault find.

I have to wait and see if it happens again, and check behind the unit.

So the loose Earth would not effect the grounding of the Power Supply.


Hazza

[budm]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Incoming AC safety Gnd is for safety, it wil not cause the circuit not to function, for example the TV or power supply that only has Line and Neutral only (those type is called double-insulated).
The safety Gnd is for the fault current.

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Incoming AC safety Gnd is for safety, it wil not cause the circuit not to function, for example the TV or power supply that only has Line and Neutral only (those type is called double-insulated).
The safety Gnd is for the fault current.

I thought it might not be the fault, when reading through the "Sceptre32 MegMeet mp116 Solved" Thread.

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

So if you look at the back side of the LCD panel, do you still see the backlights glowing when the front of the LCD panel is black?

After working fine for 6 days it has failed.

So budm I can report that the backlights flash in unison when it goes black and then blue screen NO Signal.

Black Screen- NO Backlighting ,
Blue Screen "NO Signal"- YES Backlighting.

Any Advice.

If it's the Power Supply, what components Capacitors or Transistors?


Thanks
Harry

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

If it's the Power Supply, what components Capacitors or Transistors?

Can anyone verify if they think it's the Capacitors or a Transistor.

Thanks

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Any idea, anyone

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Sorry for bumping, any advice, please

[hazzaman]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

Hi Guys,

A quick update. Fixed.

It was not a Capacitor or a Transistor as first thought from previous threads have stated as being mentioned.

For eg) https://www.badcaps.net/forum/showth...ghlight=mp116a

I tried replacing Q8 2N4011, EC7 10uF, EC8 100uF 35v. No go same problem.

Also replaced the large EC5 68uf 450V Cap. Also no go same problem.


Using a posted Youtube Video, I installed an addition 100pF 1Kv Ceramic Capacitor in series with the C36 Original 100pF 1Kv Ceramic Capacitor. SUCCESS.

The Youtube Video states that the resonant controller L6599D states the chip detects an overcurrent condition and shuts down even though there is no overcurrent. The solution consists in increasing the current limit which is done by decreasing the value of a 100pF capacitor on the PSU board. It has been changed to 50pF in this case.

I believe if the ISENS pin detects a voltage higher than 0.8v the chip shuts down, by putting in the additional capacitor, it drops the voltage and the overcurrent condition does not occur.

I even removed the C36 Capacitor and that also fixed it, but I thought adding an additional Capacitor was the way to go.

So I installed a 100pF 1Kv Ceramic Capacitor in series and it's been all good for 5 days now.

https://www.youtube.com/watch?v=esKNH-YZZYs

I hope this helps others.

[zaperbaby]

Re: GVA GVA32UA2 LED LCD Picture Disappears and Reappeares

fixed my RCA model RLC3207
I removed c36 and its working added a 68pf cap and tv still running fine must be right on the threshold of tripping the over current circuit with 100pf cap
thanks again for the link to the video