TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

[caprat]

Hello and thank you in advance for any help you can give.

I followed the necessary guidelines by unplugging different boards and realized the blinks would stop when the YSUS was unplugged. I ordered a "new" one from a reputable dealer on Ebay, plugged it in, and the same 7-blinks happen again.

Is there anything else that I should be looking for? Even though the blinks stop when the YSUS is unplugged, could it still be something to do with the power supply? I realize the 10-blinks is usually the indicator, but I've read that the 10-blinks usually follow a successful 7-blink fix anyway.

I also read that it might be a software issue killing the YSUS. No?

Thanks again.

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

7 blinks usually indicates a shorted MOSFET for the energy recovery circuit on the Y sus board but it could indicate a bad buffer board. Can you post some pictures of the inside of your TV, particularly around the Y sus, so we know what we are looking at and where everything is?

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Thank you for your help!

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Okay, please remove the lower buffer board. Be careful with the ribbon connections, they are very delicate. Disconnect the small white control connector as well as the panel ribbon connectors and the buffer board itself from the sustain board. The multi row flexible-rigid metal connectors can be difficult to disconnect, but the trick is to locate the side which is the socket, typically the buffers, and lightly pull up until they come loose.

If the lower board is at fault, the TV should power up with a good picture on the top half.

I am not sure if it will work with the top buffer removed but if it still has the 7 blinks try removing that one with the lower one in place. You might not get a picture but the screen should still glow (dim discharge) and the power LED should go green.

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Before I ordered the new YSUS I disconnected the upper buffer from the lower and the YSUS, I checked the LED, then I did the same with the lower. Both still came up with 7 blinks. I didn't disconnect the ribbons that connect to the panel. Would that matter? Once I disconnected the YSUS from the power source and main board, that's when the LED remained constant.

Also, which may be the main culprit, I think I found two 220v 900uf capacitors dead in the power supply. They're just barely bubbled so I didn't think to check them until now. Would that bring up the 7 blinks or would that just be the next issue once I fixed the 7 blinks?

[mockingbird]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Just noticed those Rubycon BXC series 220uF 250V primaries on that board... Pretty good Panasonic, using 105c, high ripple rating primaries. I just used one myself in an AC adapter.

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

I doubt the caps are the issue, but you can check with a DMM. Do you have a DMM?

The problem can also be caused by the SS board.

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Sorry for the late reply and thanks again for the help. I wanted to wait until after I received caps in the mail and replaced them. I do have a DMM and it turned out that there were three bad caps on the power supply. I just replaced them and I'm still getting the 7 red blinks. Could you elaborate more about the possible issue with the SS board? Could it be anything else?

Thanks..

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

It's a Panasonic - they use very high quality caps and they rarely fail, unlike Samsung and LG... What caps did you use as replacements?

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

I used Panasonic caps as replacements (from Digikey) - all with the same or higher voltage. I'm going to run through the process again of checking each individual board and I'll let you know..

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Okay Tom, thanks for your patience. I went through the boards once again and it still comes down to the SC board. The replacement I received was from a seemingly reputable source on Ebay with a very high seller rating. Maybe I shorted this one out as well?

I unplugged the SS board with everything else plugged in and the TV wouldn't turn on (no blinking LED or anything).

Thoughts?

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Can you post a detailed shot of your SC?

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Here is the replacement SC board.

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Okay, these marked devices are common failures on the 42" version, so I expect the 50" is the same.

Check between each pin for ohms; use 200 ohms range. For example 1-2, 2-3 and 1-3. The stub pin in the middle is electrically the same as the big fat tab on the top of the device, which might be easier to test.

If you get a reading of less than 30 in any direction for any FET, I would call that a shorted device.

Make sure the TV is off (unplugged for at least a minute) while doing this test.

[selldoor]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Your pictures are really not clear enough for troubleshooting.
Good light is the key - perhaps take the boards outside and do
pictures of both sides - without flash.
They should look like these examples

https://www.badcaps.net/forum/attach...1&d=1290283049

https://www.badcaps.net/forum/attach...7&d=1280167246

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

I had a feeling you'd pick those. I saw that issue in some of the other forums on the 42" TVs as well. I noticed for a lot of them it was a firmware issue, but there isn't any firmware update available for the 50PZ800U.

I want to trust the company I received the replacement board from, so am I to assume that as soon as I plug in another board (or the same one with replacement mosfet(s)) that the same thing could happen again? I make sure the TV is unplugged for hours before beginning a swap out so I know that I didn't cause it to short the very first time I plugged it back in.

Anyway, if you have any theories I'm all ears. Meanwhile, I'll get around to checking the board as you instructed. Thanks again!

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

Tom, the TV I use in my living room just happens to be a TH-42PZ77U that uses the same SC board.

I'm thinking about swapping it out into 50PZ800U to test it. Is there a chance that the TV could short the working SC board as soon as I plug it in? I only have one decent working TV and would rather not be without it for any extended period of time.

[tom66]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

It's possible the buffers could damage the SC. Test it without the buffers connected. Did you do a resistance check of your buffers?

[caprat]

Re: TH-50PZ800U Viera 7-Blinks, Replaced YSUS, Still Bad..

To be honest I actually don't think I know how to do that. Is it easy to explain? If not I can do some more research no problem.