Ambika LCD, ghosting pixels?

Wondering what might have caused this to happen to the LCD. It only seems to be an issue with the first 1/5th of the LCD screen, but it seems that many of the pixels in that section are faded slightly. Depending on what page the Ambika is set to, some of those pixels light up and some of them don’t, but while it doesn’t affect my ability to use the instrument, it is a bit annoying. I’m wondering if there’s an easy fix to this or if I’ve somehow compromised the LCD display.

When I first built my Ambika the display was 100% perfect (see first picture). While building my other voice cards I decided to do a little touch up work on the LCD pins. I was very careful not to keep the soldering iron around the LCD or surrounding components for too long (though my contrast adjuster did melt slightly on the outside).

Looks like the frame is a bit loose… Does pressing it make the characters come back?

Pressing doesn’t seem to do much unfortunately. I took out each screw holding the LCD down and put it back in trying to tighten it as much as possible but no luck. If I remember correctly too, this problem started to occur after I replaced one of the screws holding the LCD in on the bottom right corner (I had a larger screw in there before but replaced it with a new one you had sent me).

If it makes a difference, I have only 1 nut between the LCD and control board instead of the two mentioned in the guide. Would taking another stab at soldering the LCD pins help at all or if the LCD is already displaying characters it won’t make a difference.

This is not an electrical problem (bad connection, etc). This looks like the result of uneven pressure on the LCD module film.

In the last pic the Bezel looks bent. Try loosing the screws a bit and see if it gets better.

I just re-read the guide and I think there actually should only be one nut between the control board and the LCD. The guide says to use one bolt and two nuts. That would mean bolt-control board-nut-LCD-nut. In the photo it looks as if there are two nuts but I believe that is just a reflection in the nice shiny new PCB. Is there anything around your LCD that could cause uneven pressure on the four corners of the LCD?

Oh maybe I’m confusing terms. The screws holding in the LCD are arranged: bolt top-control board-nut-LCD-nut, one nut spacing between the control board and lcd with a nut at the bottom to keep it together.

Looking more closely on the underside of the LCD screen, I do see some slight bowing in the center. This will be an interesting adjustment to do…

Make sure the nuts that go between the control board and the lcd are not tightened until after you have the lcd fitted onto the bolts. There is a bit of play between the bolts and the holes so you want the bolts to be able to move a bit so that there is no stress on the pcbs.

If all else fails dremel the holes a bit longer so the LCD doesn’t bend!

Alright time to resurrect an old thread! I finally got some free time and am starting to try and fix the issue. I spent a good part of today solder sucking the pins on the LCD in hopes of being able to take the whole piece off and re-solder it into place. It’s been a long process so far. Still not 100% complete but I should be able to remove the whole LCD module tonight after some more work.

From playing with the pins and testing if one adjustment or another has worked, I can see that the LCD itself is not damaged (when I’ve been able to plug it in and have blocks or random characters appear on the screen, each digit of the LCD seems to be evenly backlit).

It does not seem like any particular digits on the LCD have been damaged either,but rather, the entire left 1/5th of the LCD has the display problem. Tweaking the contrast adjuster while the Ambika is powered on has caused the LCD to flash on and off a few times. I’m wondering if the issue might be related to the contrast adjuster at all?

There is a bend in the bezel of the LCD which looks like it’s near the top of the pins. I’ve been able to pry the rest of the LCD up a bit to even out the bezel but the problem still exists. Due to this I feel that removing and resoldering the LCD is the best course of action (easier said than done though).

Any insights?

Message me, I’ll buy you a replacement.