TI Voyage 200 Calculator:\r\nBlank vertical lines

TI Voyage 200 Calculator: Blank vertical lines are appearing on the screen.
The solution to this problem for Franki_01:
Where is the electrolytic capacitor?
Among U3 & U4 not see it.

http://www.datamath.org/Graphing/JPEG_Voyage200_A.htm#row
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Solution for Frankie_01:
Hi, and sorry for my english !
Maybe the LCD driver voltage is wrong or noisy. I had the same problem: some vertical lines (not constant), pulsing contrast after powerup, pixel crosstalk, sometimes no screen

Solution: Try to replace the LCD power negative voltage buffer capacitor.
In my hardware version it is in the middle of the two T6B07 column driver IC (U3&U4) on the right side. Colored black, electrolytic type and the Value is : 10uF/25V. Chage it to around the same type.
There is enought space, so you can use a small sized non smd type capacitor. Be care of the polarity.

I hope it will help... ;)

Greetings from Hungary!
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Thanks and best regards