Help with LCD (non MB)

[madox]

Hi folks,

I have just tried to swap out a dead graphical LCD on my Viscount OB-12, without success, and wondered if anyone with more experience of LCD's could please give me some advice? I suspect I may have killed the relplacement display, rather carelessly, but I'm not sure, as I have essentially no experience with these.

The OB-12 uses a 240 x 64 graphical LCD, with Toshiba T6963C controller, part number MGLS24064-67C made by Varitronix. I bought this display from futurlec as a replacement. It features the same controller, and essentially the same pinout. The display is actually a CM24064-8 from Shenzhen Brilliant Crystal, for which I have not found the manufacturer's data sheet. I don't have any specific info on the timing requirements of the Brilliant Crystal display, other than from the controller type.

I gather from the data on the futurlec site, and the Varitronix data sheet, that the two displays are essentially similar, with the following main differences (that I can see):

• Varitronix LCD uses -5V drive, Brilliant Crystal LCD used around -10V drive
  
• Varitronix LCD uses 1/64 duty, Brilliant Crystal uses 1/28 duty
  

I think the difference in drive voltage is just a matter of applying a suitable supply.

My understanding is that the duty cycle is a matter of internal implementation to a display, and should be agnostic from the synth.

Can anyone confirm this?

I bought the LCD from futurlec, as they had the best price I could find in a local reseller, and I thought the module would probably work.

Anyway, I made a mistake when plugged the replacement module into the OB-12. The OB-12's ribbon had been installed backwards, with the red wire on pin 20 instead of pin 1. I carelessly plugged the ribbon header into my new module, with the signals going to the wrong pins. I believe this actually applied a -5V (LCD drive of the original module) to the font select input of the new module, which is intended to experience no lower than -0.3V.

Once I realised my mistake, I reversed the connector back to its correct orientation, without success. I have tried running the new module with LCD drive of -5V or -12V, neither of which has worked. The only thing I have achieved is a nicely backlit blank display.

I currently don't have a scope available to monitor the signals to and from the module, though I may either borrow a scope, or take my synth in to work, to get a closer look.

So, does anyone with some experience working with modules have any advice? Should I just try again with a different module? Have I made some bad assumptions when I selected the module? Are there other critical factors for compatibility? Is it likely to be necessary to seek an exact replacement?

Any info or advice would be much appreciated.

Cheers,

madox

MGLS24064-67C.pdf

MGLS24064-67C.pdf

[Janis1279]

Some info for similar, maybe, product : CM24064-1 from the same manufacturer.

CM24064-1.pdf

CM24064-1.pdf

[madox]

Hi,

Thanks Janis. I have looked at the 24064-1 and 24064-18 data sheets, for comparison. Seems like pretty standard stuff for this kind of module, but I think they are a bit sparse on the details.

I do appreciate you finding and uploading that one for me, though. Cheers.

I guess what I would really like to know, is if my line of thinking is OK, substituting a module in this way. I wondered if I may have missed or misunderstood some factors in finding a compatible substitute.

Cheers,

madox