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Repair guides and support for Panasonic's Viera line of televisions.

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Panasonic TX-48CX400B Only backlight no picture

Sound works and screen is illuminated the back light but no picture.

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The blink code when i turn on is 14 or 15 i think it is one of them im not sure.

What does 14 blinks mean?

Update (08/06/2019)

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This is how it looks when on

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As to CN3 on the main board hopefu;;y i got this right based on the 3 12v on the schematic i formatted it starting with those

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Answer this question I have this problem too

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6 Comments:

did changing the MB change the amount of blinks on startup?

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#9 should be your stand by voltage. yours appears a bit low. It should be 5V. Can you see on your board what revision the board is?

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@oldturkey03

Here's what happens https://vimeo.com/352833830

It says R9 on the side so i think thats the revision. i found the schematic but it didnt say much info

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@awesome221 any chance you can take a close up picture of the connector CN4 and post it?

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@awesome221 mymanual for your model stops at 13. You do want to go ahead and check your mainboard and your T-con board (post some pictures of all of the boards). Since you do have backlight the main board would be the prime suspect

Update (08/07/2019)

@awesome221 there are known issues with these Vestel power supplies and no backlight (apparently the bad psu can take out the MB as well) but yours amazingly has a backlight. At this time (and since you got a new main board already) check the voltages on the connectors and compare those with the ones from the schematic. Let us know what you find.

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Updated it now, thanks for replying also as struggle to find forum for any ideas.

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@awesome221 check the Fuse F1 on the T-con board for continuity as well as power to the T-con board. If that all checks out okay my suggestion would be to start with a new main board

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@oldturkey03 Great thank you i found it difficult to find out if mainboard can cause this (no picture) and not just when on hdmi1 etc.

Im glad you said this as i ordered a tcon (£6.60) and mainboard (£23.90) yesterday but the mainboard was the heftier one that i didn't want to unnecessarily spend on.

The T-con voltage was fine on both sides 11.8v i will check continuity, hopefully it will come soon (mainboard) and i will know.

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@oldturkey03 replaced main board sadly nothing except backlight seems to flicker a little and sometimes dim a little does this mean anything, I think this happpend with the other board too?

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@oldturkey03

The blinks didnt change also from the number

Sorry about the layout last comment got flagged for spam so tried laying out on same line and punctuation, i got as follows assuming the location of the text cn4 is corect with the actual print on board and that the even numbers are the ones closest to the panel.

EDIT: I THINK THE LAYOUT MAY BE WRONG BELOW SO I ADDED IMAGE ABOVE OF CN4 DONE WITH PAINT

1 = 23.51, 2 = 25.02, 3 = 0, 4 = 0.017, 5 = 0, 6 = 3.24, 7 = 0, 8 = 3.17, 9 = 11.99, 10 = 0.45, 11 = 11.98, 12 = 11.99

PLEASE SEE ABOVE FOR EDIT

I didn’t see a cn3 on the boards

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--- will be eternally grateful.
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