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Dim/faded/unreadable LCD-display, Roland SC-33

Posted: Wed Oct 09, 2019 9:17 pm
by coldpenguin
Hello all,

I am totally new here. Currently trying to setup some sort of small home-studio with all kind of stuff.

I bought a Roland SC-33 from eBay, and it works fine - except that the display is extremely dim/faded. It is very difficult to read it. I wonder if anyone has any idea on what the problem can be?

What I've tried so far:
1. Polarization filters from Game & Watch games. Did not work.
2. Taking it apart, cleaning it and just checking if something looks weird - it doesn't to me at least.
3. Changing the internal battery - did not help.
4. Adjusting the settings internally - does make it slightly better, but very very little.

You can't see if it is turned on or not, until you get super close and look at it from an angle.

So - I'm out of options. Anyone know if this is a common problem on these machines?
Any suggestions on what to try next?

Thanks in advance.

/ ColdPenguin

Re: Dim/faded/unreadable LCD-display, Roland SC-33

Posted: Thu Oct 10, 2019 8:43 am
by Yekuku
Hi and welcome to the forum.
Sorry I havent seen an SC-33 in real life, but from personal experience there are a few causes that can render an LCD unreadable :

1) faded backlight.
2) Lcd not making proper contact with pcb
3) faded LCD

About 1) , usually you can replace the led that lights up the backlight. Sometimes the led doesnt get proper voltage due to other component failure.
About 2) , cleanning the lcd's pcb contacts with a pencil eraser and isopropylic achohol can help. In case that the lcd is connected to the pcb via a film cable, applying pressure to the contacts can help you identify the probem. this could be tricky to repair, sometimes applying heat to the joint can help , but usually you need to replace the anisotropic conductive film.
About 3) , Polarization filters can help. Did you rotate it ? Which Polarization filter did you buy ? Did you try it on another LCD , to check if it is darkening the screen? I am asking because filters from lcds and smartphones usually dont work.

Let us know how it goes, good luck!

Re: Dim/faded/unreadable LCD-display, Roland SC-33

Posted: Fri Oct 11, 2019 10:02 pm
by coldpenguin
Yekuku wrote:
Thu Oct 10, 2019 8:43 am
Hi and welcome to the forum.
Sorry I havent seen an SC-33 in real life, but from personal experience there are a few causes that can render an LCD unreadable :

1) faded backlight.
2) Lcd not making proper contact with pcb
3) faded LCD

About 1) , usually you can replace the led that lights up the backlight. Sometimes the led doesnt get proper voltage due to other component failure.
About 2) , cleanning the lcd's pcb contacts with a pencil eraser and isopropylic achohol can help. In case that the lcd is connected to the pcb via a film cable, applying pressure to the contacts can help you identify the probem. this could be tricky to repair, sometimes applying heat to the joint can help , but usually you need to replace the anisotropic conductive film.
About 3) , Polarization filters can help. Did you rotate it ? Which Polarization filter did you buy ? Did you try it on another LCD , to check if it is darkening the screen? I am asking because filters from lcds and smartphones usually dont work.

Let us know how it goes, good luck!
Thanks so much for the welcome and the tips!

1. From what I understand, the SC-33 doesn't have a backlight. So this is probably not the problem. :)
2. Maybe - however, when I took it apart, it seemed OK. LOOKED ok, that is. I did clean, with isoprop 99%, but no difference. I did not check any other components, but I'm starting to suspect some cap-damage or something similar...
3. The one I used was a Game & Watch filter from eBay - the only one I had available. Tried it both ways, no difference to clarity of the display.

Not sure on where to go from here, but I assume another dis-assembly with even more cleaning and a proper check-up of the components, I guess...

If there's no other ideas out there. :)

I tried to find a SC-33 schematics and/or repair manual, but didn't find anything. The Boss DS-330 is the "same" machine; at least the LCD should be the same - so if someone has any info on that, it might work too.

Thanks again!