Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Curious what p/n SC was correct and where did you find it in stock?

Cant remember now - but the last 2 letters of the part number that are often not quoted do denote a different part! I found it on eBay UK.

[aharben]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Curious what p/n SC was correct and where did you find it in stock?

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

The SC board was actually from a slightly different model of TV. The first part of the part number was the same, but the subsequent 2 letters were different - and although it looked identical, it apparently was not. Inserting the correct SC board has resolved the issue.

[tom66]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Got a picture of the basic scope? It may be usable...

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

They aren't chained on this model. It looks exactly like dodgy SC so can only think of one other possibility and that's bad signals to SC (or possibly SS but seems less likely)

Hard to tell without a 'scope on the outputs, can only do some basic volt checking.

I can't see bad SU/SD causing this.

I have a basic LCD digital scope if that helps.

I have tried 2 SC board swaps - both of which were tested in a working TV before shipping to me, so I think it is unlikely to be the SC.

[tw2005]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

that picture of the SC board you uploaded, is that the one currently installed?

If so , can we get a sharper picture si I can see the components and soldering up close.

Looks like a repaired board and one of the coils looks like it's bent

[tw2005]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

that's to get into service mode, then you push 1 on remote to scroll through until aging comes up, then ok, then 3 to scroll through the different patterns

[tw2005]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

if not try

While pressing [VOLUME ( - )] button of the main unit, press [INFO] button of the remote control three times within 2 seconds

[tw2005]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

not sure if thisis correct or not, was out of 50x20b

While pressing [VOLUME ( - )] button of the main unit, press [0] button of the remote control three times within 2 seconds.

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

have we tried flicking through all the test patterns in serv mode yet just in case this is A board? Is the Sc20 ribbon ok at both ends, not damaged or corroded? A removed sc20 ribbon will trigger 8 blinks and you said it was intermittent shutdown of 8 blink then just fixed itself?

I would not have expected sc would take out ss either.

No - how do I look at the test patterns?

Ribbon cable seems ok. I re-seated it to fix the 8 blinks.

[tom66]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

They aren't chained on this model. It looks exactly like dodgy SC so can only think of one other possibility and that's bad signals to SC (or possibly SS but seems less likely)

Hard to tell without a 'scope on the outputs, can only do some basic volt checking.

I can't see bad SU/SD causing this.

[tw2005]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

have we tried flicking through all the test patterns in serv mode yet just in case this is A board? Is the Sc20 ribbon ok at both ends, not damaged or corroded? A removed sc20 ribbon will trigger 8 blinks and you said it was intermittent shutdown of 8 blink then just fixed itself?

I would not have expected sc would take out ss either.

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

I have now ordered a replacement SS board to try that.

I can't see how a failure of the SC could take the SS board out too, but it seems the most likely cause...

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

I doubt the main board is bad.

It seems like it could be an SS or SC board fault but replacing the SC would generally indicate it is not SC. Can you supply photos of the SC and SS boards in your set?

Petty sure the SC board is OK now, but it was originally short circuit. Can that impact the SS board? I have not touched SS so far. The picture is still just the same as the photo above.

nb - the 8 blinks above I think was caused by loose ribbon cable to SC20 - which is now fixed.

I think it must be the A board or SC / SS as the whole picture is effected, and any other board like SU, SD or C1 / C2 would only effect part of the screen I think.

Boards are the same design / part as the attached photos:

[tom66]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

I doubt the main board is bad.

It seems like it could be an SS or SC board fault but replacing the SC would generally indicate it is not SC. Can you supply photos of the SC and SS boards in your set?

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

OK I fitted another new SC board - and behaviour is similar - the panel powers up with a complete but washed out picture. I also got a spare PSU board and swapped that out, but also no change.

A couple of times after about 5-10 seconds the panel has powered off with 8 blinks, but now it stays on. Vsus is 215V and Ve is 135V and Vad is 70V



Any suggestions how to proceed? Thanks.

The original SC board was definitely completely short circuit so i'm wondering if it's possible that the main AV board has been damaged via the linking ribbon cable?

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Have pulled it now and am returning it for another SC board. If I get the same symptoms I will start here again....Thanks.

[tom66]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

See if you can locate -Vad and Ve test points on SC and SS respectively. What do you measure on them?

[richto]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Checked with a Fluke across the 2 heavy duty PSU connections to the SC board and it reads 204.8V. Turned the Vsus pot and it goes up to a maximum of about 209 volts with no change to the display. So I guess it's likely the SC board.

[tom66]

Re: Panasonic TC-P46ST30 Fixed SC Board But Still Have a Display Issue

Around 210-215V for a high performance panel like this.