Why does my LCD look like this?

I’ve assebled the Shruthi yesterday, the power supply is ok, it plays sounds via midi, all buttons and encoders seem to work too, but it looks like the contrast of the LCD isn’t the same on its left and on its right half.When I adjust the LCD so that the contrast is good in the right half, the display doesn’t show anything at all in the left half. Can someone help me?

Here are some fotos:


Sorry to hear about that - you have a damaged LCD. Send me a private message with your address and I’ll ship you a new one.

I’m sure people here have good advice to give you about the best procedure to follow for desoldering it.

I highly recommend to listen to someone elses suggestions :wink:

Honestly, get some desoldering Braid (approx 1mm) and desolder one by one with a not too hot Soldering Iron.

Or if you have a good Dremel cances are good on the Shruthi you can cut the Legs between the Boards and desolder the Pins after removing the Plastic spacer one by one.

Thank you for your advice. I think I’ll try the method with the desoldering braid.

The method with dremeling the Pins is better, it looks in the Pic so bad because the Display was way to tight in the PCB and not accesible due to the Trimmer and Chip. In the Shruthi its way easier. Advantage is you can then remove the plastic spacer from the pins (i remove them everytime i mount a LCD- just in case. I can then desolder the pins by grabbing them with pliers and heating them between the boards) and desolder the pins one by one.

This is a wise decision, i thought about while mounting the display of my LXR, but when i get my new display to repair my old Shruthi i will do it definetely…

Actually with my fine NoName Chaiwaneese 80W regulated soldering station its near joy… touch a bit of solder to a pin between the boards, grab the pin, heat between, wait 5 seconds, pull the pin out. Did this on the LXR 2 times…
Next tip: leave out the middle 4 Pins on the Shruthi they arent connected anyways…

That tip would be great right in the Assembly Instructions!

i had to desolder an LCD recently.

patience, flux, braid.

@fcd72: :) “… good Dremel cance®s are good…” yes I read somewhere cutting fiberglass PCB is not so good for health :wink: Let your staubsauger with hepa filter “inhale” the dust.

@neoplamsa: If there is enough space between LCD-PCB and the PCB it is soldered onto, you can cut each pin with good side-cutting pliers, the one you use to cut legs away from components…

Then follow the “pin-by-pin pull out” described above, next step: clean holes with solder-pump or braid, stresses the solder-pads less, than only with solder braid (cookcookcook-ohh there is something coming off the PCB, looks bad, need to clean this: just strip it off, mist, that were the lanes+pad)
Also: apply flux on solder joints before de-soldering on the solder points, makes it easier.

I thank you all for your advices!

I tried it with a desoldering pump and braid only, but I wasn’t successful (despite a lot of patience and flux). At least I didn’t damage anything yet. I don’t have a Dremel, but maybe I find a suitable side-cutting plier as MusicCircus suggested to cut the legs away from the components.

Ideally you just want to get the LCD off the pins and re-use. Otherwise you’ll still need to desolder the pin header from the PCB and that’s where the damage is more crucial.

I finally made it!
I desoldered the damaged LCD exactly as MusicCircus told me. That way it was quite easy and fast. :slight_smile:

I decided to change LCD on my second shruthi that I use with lp2+delay or digi/fx board (I swap the filterboards occasionaly). I think I haven’t used this shruthi as much as my polivoks shruthi only because of that ugly LCD display. So I replaced LCD with an OLED, using side-cutting plier method, it was very easy actually… OLED works fine, but I get a sound with lot of noise with digi/fx filterboard, whereas with lp2+delay I don’t get any sound. I think I’ve pulled out a bit the solder pad on the controlboard PCB where the last pin of “display header” goes to (solder pad that is closest to the MIDI connectors). So, if this could be the cause of my problems, how do I repair the broken solder pad?

edit: I tried to power it up again with digi/fx board, after some time I got some weird symbols on display. then I powered it again and all the LED’s lit up. and now it won’t even power up again…

So, as far as I understand I can only repair broken pad by connecting it with wire to other stuff that this pad used to be connected to. So to which spots should I connect it?

I tried lp2+delay and digi/fx filterboards with working polivoks controlboard and it seems that my new oled destroyed my 2 filterboards too… I think I’ll just throw them in the drawer for the next 5 years until I finish my Electronics University, I don’t feel able to fix this at all…