50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks for the prompt instruction.

No luck to get any numbers like 200V. I noticed that, when I pressed "ON" on the remote controller, the VS voltage goes up gradually to 10 V and then the TV starting sound (Samsung chiming?) comes and the voltage keeps at 10 V.

I removed the connector to the logical control board and got the same results.

Any other testing? or clues? Thanks.

[JonathanAnon]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

No luck to get the voltages back. Without Y-main, the VS is 0 V and VA still 0.1 V.

I had a similar plasma with similar logic board blinking LED + Sound and no picture, and found that Vs would not come up with the Y Sus and Y buffer disconnected, even though I had forced PS_ON and VS_ON ... This had me thinking there was something wrong with the PSU as well.. But when I bought the new Y Sus + buffer and plugged it in to the PSU, the VS came back online and the screen came on..

I guess my point is, that it could be the case that the Vs will NOT come on unless it detects that the Y SUS is connected..

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks for the quick input JonathanAnon.

It might be, as first (about 2 years ago) I got some horizontal thin lines from left to right and only early this month the TV went down (no screen but with sound). tom66 suggested to replace Y buffer too.

So next step I will replace Y Sus + buffer and keep you guys updated. Do you have any good sites to get them? Thanks.

[JonathanAnon]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

So next step I will replace Y Sus + buffer and keep you guys updated. Do you have any good sites to get them? Thanks.

With regard to the Y SUS AND the Y buffer that I replaced.. I had to replace both for a number of reasons:

1. I suspected there were faults on both Y Sus and Y Buffer, and
2. I was worried that if I bought only one board and there was a fault on the other, the fault on the other board would blow the replacement.
3. I got a good deal on buying both together from a company in the UK...

It was the safest option for me in that particular scenario..

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thansk for the input JonathanAnon. That's really a smart idea if it doesn't cost too much :-).

I will keep you guys posted after replacing the Y sustain OR the Y buffer.

[JonathanAnon]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

I'm not sure if there anything further that you can do at this stage to verify that the PSU is good... which is the question that I was asking myself when I had the Y Sus / Y Buffer removed and still the Vs voltage did not come on..

I had to take a leap of faith based on the evidence and I guess you will have to do the same.. good luck.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Hi guys, here is an update.

I received the parts today: Y Sus, Y Buffer and Power Supply unit, installed them but the problem is not gone, got similar voltages as before (see the 2.1) section "with all connectors connected" in the pdf attachment on #17 post on the previous page):

1) got the voltages with the connector to the Y-Sustain board:
VS: 9.6 V
D15V: 14.6 V
VA: 0 V

2) got the voltages with the connector to the Video board:
PS-ON: 0.1 V
STBY: 5.2 V

D15V: 14.6 V

D5.3V: 5.2 V
D5.3V: 5.2 V

D15V: 14.6 V
D15V: 14.6 V
D5.3V: 5.2 V

3) got the voltages with the connector to the Logica control board:
D5.3V: 5.2 V
D5.3V: 5.2 V

PS-ON: 0.1 V
VS-ON: 0 V

So does it mean that other part(s) caused this problem rather than these replaced three? Any clues and inputs on it are appreciated.

Thanks.

[anno]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

if the ps-on is only 0.1v , i think the power supply is not turned on by the logic board , the same for VS-ON. does that voltage change when you turn on the TV?

[tom66]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

On many Samsungs a low PSON means the power supplies should be on, but the low VSON means the VS should be off (no idea why they used different polarity for each...)

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks for the input anno and tom66.

to answer anno's question, the voltage changes from 3.3 v to 0.1 v when turning on the TV.

BTW, the logic board doesn't have the small light blinking, is it broken? does it affect the VS voltages from Power supply board as the VS voltage became 0 v since the light's blinking on the logic board was gone.

Thanks.

[tom66]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

The LED on the logic board should be blinking. There is usually a fuse or two on it, test those.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks for the quick response tom.

Following your instruction and tested the only fuse (5A) I can find and it's broken!

You're correct on that, the green LED blinks again after replacing with a 3A fuse as I don't have an exact same one when turning on the TV.

However, the problem is not gone yet with the newly bought Y-Buffer, Y-Sustain and power supply installed and the fuse on logic board fixed, the screen is still black (no glow) but with sound. I noticed voltage changed as following when turning on TV (especially VS and VA):

1) got the voltages with the connector to the Y-Sustain board:
VS: dropped from around 190 V (±10 V) to 10 V
D15V: 15 V
VA: dropped from around 54.7 V to 0.2 V

2) got the voltages with the connector to the Video board:
PS-ON: 0.1 V
STBY: 5.2 V

D15V: 15 V

D5.3V: 5.2 V
D5.3V: 5.2 V

D15V: 15 V
D15V: 15 V
D5.3V: 5.2 V

3) got the voltages with the connector to the Logica control board:
D5.3V: 5.2 V
D5.3V: 5.2 V

PS-ON: 0.1 V
VS-ON: 0 V


What next testing I need to do? Thanks a lot.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

An update is that after disconnecting the ribbon from logic board to Y-sustain board, the voltages for VS and VA are normal: VS=211V and VA=54V, matching the numbers on the sticker of the panel, but if connecting the ribbon back, the VS and VA voltages drop gradually to 10V and 0.2V.

Another thing I noticed is that while the newly bought Y-Sustain board was installed and powering on the TV, I could only hear one "click" sound and the TV was off automatically, after few trying of turning on TV, the remote controller didn't work any longer, but it works again after unplug the power cable from the wall outlet and re-plug it. Does that mean the bought Y-sus board is a defective one?

Any inputs and clues are appreciated.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Is anything wrong with the logic control board?

[tom66]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

I am thinking your Y-main (Y-sus) has a short but it is only apparent after the control board attempts to control it. Have you tested any of the transistors on it for shorts?

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks for the advice tom, do you mean i need to check the ones on the newly bought one or the original one?

1. the newly bought Y-Sus, while connecting the power connector with the power supply unit, it has a short "click" and the TV turned off automatically.
2. the original one, while connecting ribbon from the logic control board to the Y-sus board, the VS and VA voltages drops to 10 V and 0.2 V respectively from their normal numbers.

Thanks.

[tom66]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Test the new board. I think both are bad, in different ways.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Thanks tom.

I contacted the website I bought the parts and the technical support confirmed the board is defective after asking me some questions on the problem symptoms with the board installed and they are sending me a replacement, thanks for the correct instruction! will keep you posted when receiving the other replaced Y-Sus board.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Hi Tom,

Just had some time back to my TV fixing work, I got the parts from different sites and replaced the Y-Sustain board and Y-buffer, but the problem is not gone, there is still sound (noise) but no videos at all, the VS and VA voltages look matching the ones on the label of the panel. I recorded a video clip which will show you some details, which you can download it by clicking the link ftp://fm76whcq.ftpserver.acanac.com/...g/100_6383.zip (with a username of "ftp@fm76whcq.ftpserver.acanac.com" and no password).

Can you please let me know what's the next steps I should should do? Thanks for the help.

[sangdy]

Re: 50" Plasma Samsung TV (Model code: PN50C540G3FXZC), sound without picture!

Can anyone help?

Thanks.

Hi Tom,

Just had some time back to my TV fixing work, I got the parts from different sites and replaced the Y-Sustain board and Y-buffer, but the problem is not gone, there is still sound (noise) but no videos at all, the VS and VA voltages look matching the ones on the label of the panel. I recorded a video clip which will show you some details, which you can download it by clicking the link ftp://fm76whcq.ftpserver.acanac.com/...g/100_6383.zip (with a username of "ftp@fm76whcq.ftpserver.acanac.com" and no password).

Can you please let me know what's the next steps I should should do? Thanks for the help.