Modifying a 240x64 LCD to bypass the onboard display controller

[hb129]

Hi there!

I've got an old sampler and I'd like to replace the LCD display with a backlit modern equivalent.

The only problem is that the original 240x64 LCD display does not have a controller IC built in (it is powered by a controller from the main PCB) and I can only find modern replacements that have a controller built-in to the LCD display.

I have heard that people have been able to modify Winstar WG24064A displays (controlled by RA6963) to become "controllerless" by removing some components and bridging a few pins.

I've only been able to find some really lo-res images of the modification so I'm not 100% sure which pins to bridge across after removing the RA6963, I've attached a photo here.

I think they've removed 2 ICs - the RA6963 and another IC above it which I'm assuming is an SRAM chip. There is a datasheet for the display here (no schematic though) https://www.winstar.com.tw/products/graphic-lcd-display-module/240x64-lcd-display.html

The datasheet for the RA6963 is here:
https://www.newhavendisplay.com/app_notes/RA6963.pdf

The datasheet for the original LCD in the drum machine is here:
http://www.sdiy.org/xyzzy/MPC60/LCD/LM24008M_25_Feb_87.pdf

I'm not 100% sure but I think pins 18-21 of where the RA6963 was located are bridged to other pins (I think 2 pins between 50-54) as well as 2 pins from 55-60.

I think there is also 1 pin going from 55-60 to 1-5 but not sure.

I think I've got an approximate idea of what's going on but would appreciate any additional advice, I'm not 100% sure about where I should be bridging pins.

Many thanks

[Buriedcode]

Yeah the controller is an equivalent of the T6963C which were ubiquitous for those displays.  To make it "controllerless" you do indeed only need to remove the controller and SRAM.  ]

It might also have built-in DC-DC converter for the -VEE required by the display (about.. -12V I think..) that should be enabled after the control signals - if your new controller board provides this you will need to modify this part as well.

I am assuming the control signals your new board provides are the semi-standard  FR/CP1, LP/C2, DATA, S, M etc.. but off the top of my head.. I think these signals are different from the 4-bit interface of larger panels, so only 5 signals required.  If you compare the original LCD's datasheet to the RA6963, then it looks like...:

orginal LCD - RA6963 name - pin number
CP1  - LP - 55
CP2 - SCP - 53
S  - FLM - 59
M - M (FR) - 57
DI - D1 - 56

I could be wrong here!

So yeah, looks like a bit of an arse to map out pins - especially as the original t6963C was a joke, and the newer RA6963 ain't much better in terms of pin names  (they happily use LP and CP1 interchangeably) it certainly can be done.  My only additional advice would be to check the outputs from the original board on a logic analyser to double check that the signals are what you think they are.

Otherwise you'll have to use the original LCD's datasheet pinout to find the signals on the original board.. and the RA6963's datasheet to find the corresponding pads on the RA6963s footprint on the new LCD, whilst you can keep track of that, there's a lot of room for error.  With that said I can't see you permanently destroying anything - except perhaps the outputs of the original boards if they were shorted to ground, but a quick continuity check will prevent that.

Ok so my only advice would be... use a pin header and socket and decide on your own pinout, so that when you mod the new LCD you know the exact pinout of your connector, and the same with the old board.  That may sound obvious, but when patching wires directly it can become a mess very quickly, and you can lose track of what signals are what.

[hb129]

Thanks for that info, I agree the pin names are very confusing! I've never used a logic analyser before but I guess there's a first time for everything. I've run into some additional problems with the sampler so I'm thinking this mod may take a back seat for a while ...

[Bjarni Raf]

Hey im on a similar mission for the mpc 3000,, been trying to figure out the pinouts comparing them to the new ones and that sanyo contrller,

But i was wondering, and sorry in advance if this is a stupid question.
Is it possible to remove only the display part of the lcd and switch them? Im not sure how the led backlight is mounted on the pcb, weither if it is a panel sitting behind or if its soldered on the pcb?
Just wondering,

Im still in the process of choosing which new lcd i should buy, now Im  leaning towards the winstar as well

[Bjarni Raf]

My previous idea was to get some led panel customized for backlighting, it can use the 5vdc which is powering the inverter to power that backlight.

https://goo.gl/images/aGNzV8

[Bjarni Raf]

The user Flub from mpc forums has successfully done this hack, so its just a little hassle finding the right display that will fit the old display pcb


http://www.mpc-forums.com/viewtopic.php?f=4&t=148831&sid=54a4c27ccb270d8206dc8c624aa5b757&start=30