Ribbon controller cause gray screen

striphio · Post by **striphio** » Sun Jan 08, 2023 1:54 pm

Hi. I had problem with pa4x screen last night on gig. Screen suddenly goes gray with some vertical lines. I tried to restart keyboard several times, moved screen but no luck. Screen is always the same. Sounds and everything other work fine, screen is also working, but cant see nothing what I pressing. Fortunately, I have second keyboard and live band so gig goes on without problems.
Tomorrow at home I turn on pa4x and all was fine again, screen was normal. I search forum and find some "karmathanever" post about some screen issue. Its somehow connected with ribbon controller. So I touch ribbon on pa4x and touch screen and same problem appeared again.
Any thoughts?
https://ibb.co/v19xC5c

musiccankill · Post by **musiccankill** » Sun Jan 08, 2023 3:10 pm

This doesn't seem to have anything to do with the ribbon controller.The ribbon controller doesn't even connect to the same board as the screen...
Most likely it is a screen or cpu board issue or the connections between them.
If you open and close the screen a lot , it could be the flex cable that has gone bad.
Can you put a link on the post that Karma did say something like that?
I remember a touch screen issue where when you touch something metal on the keyboard it starts detecting correct touches again (maybe it would do it with the ribbon touched too) but never seen a screen going bad that way yet.
Keep up posted about what happened!

striphio · Post by **striphio** » Sun Jan 08, 2023 3:53 pm

I also don't know how ribbon and screen are connected, but, like I said, day after, when everything was OK with screen, I was moving it, touching, and all thing I remember that I could done it when problem appeared, I didn't manage to recreate problem. When I readed this with ribbon, I touched ribbon and touched screen and bingooo, problem appeared instantly.
Here is the link http://www.korgforums.com/forum/phpBB2/ ... c0d9725456

Now I reading it again, and not sure what ribbon he is talking about, connector or cable...

But still not sure how this happened when i touched ribbon controller and screen.

striphio · Post by **striphio** » Mon Jan 09, 2023 10:34 am

Today is always in "gray mode". When I swipe with finger on upper left part of the screen it response like changing brightness or something similar.

https://youtu.be/DloJL_8jUqo

musiccankill · Post by **musiccankill** » Mon Jan 09, 2023 5:46 pm

80% is the screen (actually the pcb behind the screen but they are sold as a module) ..
If you press any other button like global or media does it respond and change what is shows on the screen (not show correctly but different)?

striphio · Post by **striphio** » Mon Jan 09, 2023 9:50 pm

musiccankill wrote: If you press any other button like global or media does it respond and change what is shows on the screen (not show correctly but different)?

Yeah, it change, but still can't see anything. Also you can select things on blind.

musiccankill · Post by **musiccankill** » Mon Jan 09, 2023 10:46 pm

You have to either open it up if you know what you are doing or take it to a repair shop.
First move is to reseat all flex cable strips and if that doesn't fix it, replace the screen assembly would be the next logical step.

striphio · Post by **striphio** » Mon Jan 09, 2023 11:00 pm

Thanks for your help. I will open it and try.

musiccankill · Post by **musiccankill** » Mon Jan 09, 2023 11:03 pm

Be careful and best of luck!
If you need more help pm me and hopefully i ll be able to help