Mulja tv repair portal
Equipment Repairs => PLASMA TV forum => Topic started by: Sven76225 on October 10, 2010,15:08:52
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Hello,
I am a television engineer and need help.
:sign0085:
A 50PC51-ZB TV television stands on my desk.
PDP Model : PDP50X40D46
Mistake:
- No picture and no OSD insertions
- Sound available
A visual examination was carried out.
The front LED shines after him switch on permanently green. The screen is getting light for half a second. It appear, on top on the right in the corner to letter. However, these are very difficult to recognise.Complete screen black.
The operating voltages VA, VS, 5 V, 3.3 V exist. The fan works. On the 50X4A_CTAL_256 board all SMD DIODES SMD shine except D1 and D2. These diodes are nearby to IC 101.
I measure on the power board
Plug P800 ( See appendix ) Picture 1
The voltage 3.4V_ON is higher. The voltage value is 4,48 V. Where the voltage is generated. Have a bad circuit diagramm. From it this is not award. :03:
On the signal processor Board (board name : 50X4A_CTAL_256CH Patr No : EAX37080201 REV : F) is an oscillator (see figure appendix). On the signal processor Board is an oscillator (see figure appendix) I measure To the resistor (R51) 3.3 volts!
I measure to the voltage converter, unfortunately only 5 V and 3.3 V. Where I measure 1,8 V and 2,5V? I need a better circuit diagramm. Please !
Thanks for your help.I wish a nice weekend.
Greeting Sven
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Hi Sven 76225,
No ideas, never met one, no manual, but feel should reply as had a good and sunny week-end, and your entry was the ideal - full details, circuit info and piccies - who could ask fer more.
No Basil Fawlty stuff - local folks,
Now to try make some cash - Chris.
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Hello Chris,
thanks you for your answer. :08: I have clamped the modules. (Buffer Modul´s upper and lower). One after the other! Upper and lower picture half is not shown. View check of the modules was unobtrusive! No dark places obviously. I have added the appendix some picture. The first picture shows the Y-Wavefrom. Unfortunately, not correctly. :41: (The Probes have the setting 10:1) (DC voltage = -2,30)
What I could still test?
Regards, Sven
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Hi again Sven,
Sounds like one for our very own 'Brian the Brain' as it's slightly more technical than double-dipped Conkers - Bri's speciality, that none but our 'Sparky' can comprehend - Chris.
PS - Admit it's a taste aquired - or perhaps not.
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Hi Sven,
it could be a psu problem but as you know the diagram is not available.anyway take a look at the manual,can get some ideas.Cheers.
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Hi Cheers,
thank you for your answer. I will check the power supply again. I have the circuit diagramm.The circuit diagramm is unfortunately very poor. It is not a detailed schematic. :-( I will search an other Circuit diagramm. To understand how the process works. What signal must be present at the scaler ? Reference signal, Which is transmitted via the LVDS cable. What are the most important parameters (Oscillogram).
regards, Sven
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Hello!
I am looking for a table. A description of what symbolize the LED's. D1-D4 on the CTRL Board. Can you help me?
Thanks for your answer.
regards, Sven
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hi sven,
usually the LED's onto a LG chassis do not indicate an error code but the presence of various voltages.bye
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Hello Michael,
thank for your answer. Do you know, which voltage missing? The LED's D1 and D2 are off!
Best regards,
Sven
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Hello! I have the Y-Drive Wave measured signal. Duty ratio 10:1. The sweep time I have multiplied by 10.(Please note this to the graphics.[see appendix])
Can I assume this is therefore the YSUS Board in order?
What signal is still important?
Thanks for your answers.
kind regards
Sven
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Hello,
I am a television engineer and need help.
:sign0085:
A 50PC51-ZB TV television stands on my desk.
PDP Model : PDP50X40D46
Mistake:
- No picture and no OSD insertions
- Sound available
A visual examination was carried out.
The front LED shines after him switch on permanently green. The screen is getting light for half a second. It appear, on top on the right in the corner to letter. However, these are very difficult to recognise.Complete screen black.
The operating voltages VA, VS, 5 V, 3.3 V exist. The fan works. On the 50X4A_CTAL_256 board all SMD DIODES SMD shine except D1 and D2. These diodes are nearby to IC 101.
I measure on the power board
Plug P800 ( See appendix ) Picture 1
The voltage 3.4V_ON is higher. The voltage value is 4,48 V. Where the voltage is generated. Have a bad circuit diagramm. From it this is not award. :03:
On the signal processor Board (board name : 50X4A_CTAL_256CH Patr No : EAX37080201 REV : F) is an oscillator (see figure appendix). On the signal processor Board is an oscillator (see figure appendix) I measure To the resistor (R51) 3.3 volts!
I measure to the voltage converter, unfortunately only 5 V and 3.3 V. Where I measure 1,8 V and 2,5V? I need a better circuit diagramm. Please !
Thanks for your help.I wish a nice weekend.
Greeting Sven
After 13 months of ownership (just past the warranty expiration) my LG Plasma TV developed a serious problem. These include picture degradation, shutting down at random, screen lines, color degradation and others. We systematically applied solutions such as switching cable locations, using different cables, trying a variety of power supplies (basic strips to battery backup) and nothing seemed to help. We observed the TV in different modes and kept having the same problems whether we were using the Set Top Box (cable), the DVD player or the gaming system. One observation stuck out form the rest – the problem did not occur when we were watching a black and white movie. But as soon as the film ended and we switched to a color movie, the screen popped and went blank.
I started researching the issue on-line (thank you Google!) and after some trial and error with search terms eventually discovered other plasma television owners with similar problems – some have been kind enough to post pictures and videos that allow me to see the same problems as my plasma TV. Further investigation revealed that a common culprit appears to be the Y and Z Sustain Boards. These circuit boards are akin to the vertical and horizontal deflection circuits of older televisions and are at the heart of creating a picture on the screen.
Unfortunately, the Y and Z Sustain Boards (more simply called the YSUS and the ZSUS) are a serious weak point in ALL plasma televisions. Do a Google search for problems with plasma televisions or problems with these boards and your search results will light up with hits! Information about problems with these components span years of plasma manufacturing and cover a wide variety of brand names. The worst offender seems to be LG – especially since they manufacture these boards as components for many other brands and have been doing so for many years.
Doubly unfortunate is that this problem seems to be rampant in the plasma television industry yet no one seems to know about it. It does not seem to be a safety issue (no fire hazard, etc.) so the Consumer Product Safety Commission has no information on it, it is a standard component of larger items with no particular brand involved, so the Better Business Bureau has no records on it, and the issue is spread out and technical enough that the average consumer seems to be unaware that it is such a large issue. How many plasma TV owners have to have this problem before it becomes general consumer knowledge?
In other words – this is a KNOWN ISSUE with plasma televisions yet it has somehow fallen through the cracks of consumer knowledge and the plasma manufacturing industry is certainly not bringing to anyone’s attention.
A call to LG customer support was less than helpful. The customer service representative on the other end of the line had no information on this issue (even though it is quite common). I knew more about the inner workings of my television than he did. The LG warranty does cover the “Panel” for a two year period – and these components would appear to be core to the “Panel” – but the service rep I spoke with could not provide me a definition of what is included as part of the “Panel”.
To put this in perspective, my family once owned a Sony Trinitron for nearly 20 years before it was replaced and our former primary television (still in service) is a nearly decade old Sharp CRT unit. Neither of these units developed the problem this LG Plasma is having and neither ever needed to sort of repairs (both dollar and labor wise) that this plasma unit needs. So yeah – this is big deal. When I spend the kind of money necessary to purchase a product such as a television, I expect to get more than 13 months of service out of it. I intend to get this unit repaired or replaced and I do not intend to be the one paying for it!