emusonacid!

I just got hold of an E4 from an ebay vendor. It is not an original since it has the second midi upgrade installed and I understand that the original E4 did not permit any upgrades.

It has a problem with the LCD in that the left two-thirds shows no content and there are two narrow horizontal bands in the top half of the remaining one third where the pixels are left out. There is no back light but I don't know whether that is normal or otherwise.

It seems to boot fine (the 'EOS' message is visible on the right (functional) part of the screen) with part of the messages [like the amount of memory installed] visible in the functional part of the screen. After boot it gets to the 'fader screen' but only the channels from 10 to 16 fall into the functional part of the screen.

My guess is that the LCD controller is working (since the content seems reasonable where the content is) but the driver chips on the LCD have gone south. So, I could rework the solder joints on the LCD drivers of the LCD or ...

Has anyone else come across a similar problem? [I didn't find anything in the forum about it]
Does anyone know of a replacement part? [I have 2 x E4XT Ultras and an E5000 Ultra but they're functional so I wouldn't want to savage them for parts]
Does anyone know of another solution?

I fixed the problem.

After extracting the LCD module from the front panel assembly, I noticed that even less of the pixels were functioning, and that by pushing the LCD against its PCB different blocks of pixels became visible. This type of LCD module has a metal bracket holding the PCB against the LCD screen proper and it seems that the contact is made by 'physical compression'. The metal bracket generates this compression with 10 'tabs' that are bent inwards over the PCB. On this particular module only two of the tabs were bent inwards and apparently the trip was enough to remove any residual contact in a number of areas.

I turned in the other tabs (using a pair of pliers) and voila - the problem resolved. All pixels now present and accounted for.

I'm somewhat surprised that so few of the tabs were bent in place original. I was relieved that the solution was so simple.