LCD replacement problem (Roland MC-500)

[Don Solaris]

So i bought a new LCD for my Roland MC-500 MkII. Existing one from 1988 (Sharp 20256B) uses the standard HD44780 controller. The new one i bought is based on KS0066, thus compatible with HD44780.

For some reason, i get no character output at the new LCD. I wonder, could it be that the Roland's I/O gate array is "too slow" to feed the new generation LCD electronic?

Some quick infos:

• Pin layout on the both LCDs is 100% identical.
• I've installed the trimmer to set up the contrast, and no matter how i turn it, no characters appear, though the contrast control clearly works.
• All the wires are correctly soldered. In fact i've installed the strip connectors, so i can quickly switch from one to another LCD.

If anyone has any experience with LCD replacements, any clue would be welcome!

Thanks!

 

[kazper]

If the wiring is done wright it's either incompatible or defective.

Most LCD's show a display flicker on power up or show solid dot fill then go blank as indication it has power. As far as the data bus question if it was compatible then it was made to the same specifications as the HD44780 so it would be a non issue. The devil's in the details and there may be pins that need to be assigned for a specific mode etc so consult the data sheet. Toss some pictures of the controller chips or links to the data sheet up and have another set of eyes look.. 

It's really no different than changing out my Sp-1200, S950 displays slow old electronics with the latest and greatest LCD China has to offer.