I posted this same question on one of the other synth BBS's...How bright is the backlighting on most D-550s today? I just bought a used one on eBay and I am disappointed at how dim the display is. There is some backlighting and I can read the characters on the LCD, but I have to be fairly close to the display. It is actually more difficult to read the LCD with all other lights off in my studio (unlike all of my other LCDs) than with decent ambient lighting. The backlighting on my M1R must be 5 times brighter!

The person from whom I purchased the unit offered me a full refund, but claims that the D550s had poor backlighting to start with (even mentioned that "Roland engineers caught hell" for it!). Any opinions? (I realize it is difficult to discuss - via a medium in which vision is impossible without certain equipment - something that is so dependent on vision alone....)

This person you purchased it from is correct, the D-550's have a pretty dim display anyway. Mine has almost no backlight at all!

I just bought a used one off ebay also.

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Clayton L. Workman
cworkman@ieee.org

I had my D50 apart a year ago, and I'm not quite sure but I think I saw a pot to trim the contrast.

Yes, there is a "pot" to adjust contrast, but this has no effect on the backlight. I returned the D550 for a full refund, by the way.

The dim light is a natural phenomenon that's happening when the backlight gets older.
I got in contact with a electronics supplier and they thought that it would be possible to change the backlight. I will give it a try and at the same time get some info how complicated it will be.
As soon I have tried this I will reply to this forum and let you know what's happened.
I am afraid that this is not a every-mans-thing to do and I will strongly advice someone to do this operation whitout some formal electronics training. The worst thing that can happen is that you damaged the display and whitout the display the synth is useless.
So keep looking and maybe I can get back with some good news for you and maybe also a schematic layout how to fix this thing.

PEO!