Is this a possible solution for LCD Juno G screen??

[rrete]

Hi to all!
I haven’t seen a presentation sub-forum. I’m from Spain a have several Roland Synths like, JX8P, D50, D20, W30, U20, JV1080 and a TR8S and other many stuff. I like 80’s keyboards.
I have got a Juno G that I bought with two issues, channel R did not work (today fixed) and the well know LCD issue. Tried to fix the LCD with no replacement, the results are no stables only ¼ upper right seems to work without problems. Because is hard to find original LCD and expensive, contacted several distributors like instrumentalparts in these days say are reengineering a new one, and others here in Europe haven’t stock.
Like a vintage computer collector, I’ve seen proyects to use new hardware in old computer using raspberry and arduino translating old code from the computer to new code of the hardware to work like USB mices, keyboards, Gotek and more. I’m working in computer support but I am not a programmer arduino may be a possible final solution to this problem using it between Juno and new and more cheap LCDs or even TFTs. I’m going to explore this by myself but if there is somebody in this forum that know arduino or another kit can do this will be interesting.
Any ideas?

[chirath22]

Hello
I'm on same the boat,I'm also searching for an aftermarket display and connect with such an interface that you're mentioned - raspberry or Arduino. but I'm too looking for the correct information. because the data patten and LCD design are different from the manufacturer. on FB i submitted the wuest\io9n and one person replied to me with some valuable ide and I'm waiting for his update. once I get it I will share it with you

Chirath

[rrete]

Hi!

I hope we can do this modification. Several days ago I contacted with a person who knows a lot of arduino it's a electronic engineer. Tell me that it's
totally possible. He had to do something like this in the past with industrial equipment like laser cutting machines. Had two problems, that in first sight will be the same for juno screen. 1. As far as i know the lcd protocol of the juno-g is propietary of Roland no a standard, information about this is needed and 2. reverse engeenering or how to traslate juno code to standard lcd because is not a character lcd is graphical lcd so more complicated.
I'll like work on reading juno lcd bus with arduino but for now i've no time.
For Screen of 240x96 i've found but if this can be done better develope this to use color tfs or conect to external screens even.
Of course newer improvements i'll share too.

THX

[alexdeglialex]

Very interesting solution. Hope it's a definitive solution.
I wonder if the lcd fault is correlated with firmware version. The fault appear in all the Junos after release of vers. 2 of firmware.
In my personal experience I've verified that when the screen didn't work fine (some part black, or similar fault) not all the function of the workstation were accessibile (for example, it was impossibile to play midi file).
It was interesting to know if Juno with original firmware, and never upgraded, have had the same fault.

[rrete]

My juno had a ver 1 of firmware and had screen problems. Upgraded to 2.0 and the same issues are present. No test midi problems and I can't say if they appear at the same time.
Maybe, because no information about how the lcd bus works can be found, the problem is the bus itself. No code than electronic components.
The screen only has the drivers to present information, as fas as I know basically all electronics are in the logic board. So I think that arduino can make this.

First step is read the code of the lcd screen flex. Any idea about how to do this?

[eduposada]

Hello guys. After reading this topic, I am very hopefull someone will come up with a solution for this terrible problem.
I have this keyboard too in Brazil (my home), and now I am living in China for a while. After leaving Brazil, I was using the keyboard through midi attached to a computer. I was using an old editor and librarian provided by Roland. But it doesn't have all features. I could only select combis/patterns to play or edit them. The live functions and playing or recording songs were not available. The editor doesn't access the main configurations too. Very limited.
But my doubt is: is it possible to create a new editor with more functions using midi messages to access all functions? It could run on PC or Mac or else be developed as an APP for IOS or Android, using wifi or bluetooth midi.
What do you think about it?

[rrete]

Hi!
Maybe you say is another good solution. The question who do this? I think is possible too.With a little/compact computer that support Win XP and a 7'' or smaller screen the problem will be fix.

[eduposada]

rrete, I think an app developer or any developer in java, pyton or even in C++ can do this.
The starting point would be mapping all keyboard processes (all the menus). Than, mapping all sysex messages, in order to establish the communications between the keyboard and the platform where the app will run (PC, tablet or phone). And the last phase would be to code the program (app) to mach the logic map built on phase one, with the I/O obtained from phase 2.
Not very easy (also not difficult), but I think it is possible. The only doubt I have is if all keyboard's functions can be controlled by sysex messages...

[Totò64]

Hi everybody!
By my experience I found the display problem is based on two factors; the building quality of the display itself which is poor indeed, and the connector of the flat cable located on the CPU board, which gave faults on the display everytime I touched it. I tried to resolder this connector and I put a piece of plastic sheet behind the flat cable edge and seemed that by this side the problem was solved. By the display side it's another matter. Does somebody know the model of Controller IC of the display ? I found several displays in Europe and before purchasing one of them I need to have this part of the jigsaw to try to solve this problem. I'll keep you informed.

[Totò64]

Goodmorning,
does somebody know which IC controller is used for the LCD display ?
Basing on such info I should be able to provide an alternative display to be installed onto the Juno G.
Please help!
Thanks.

[rrete]

good news eduposada!
Really I don't know if sysex roles the keyboard I think sysex maybe only can use by midi ports. Internally must be a propietary software. my first idea is or was translating on the fly the data of the flex that came from digital board to the LCD in order to use some kind of display that can handle the informatimation like a TFT or another graphic LCD screen. This process made by arduino or similar.
Thx for your interst.
Toto64 looking at the service notes the LCD is directly connected to the internal data bus of the digital board, so I think is controlled by the CPU IC1 SH-3/7706
Cheers!!!

[leonsun]

Do I understand properly that the display is controlled by the digital board and not by a display controller?

[rrete]

Hi leonsun

I'm not an electronic technician but in the service notes documentation, exactly in the block diagram i can see that the bus of the LCD (flex) is directly conneted with th CPU. In the digital board, where the LCD is connected y can't see any chip driving it. I'm think all this is correct.

[dpeddi]

Hello,

I don't have the keyboard yet. My friend should give it to me within some days.

Please try the sketch from following site:
https://forum.arduino.cc/t/lcd-1602-and ... fer/675769

Configure the sketch for 8bit and leave disconnected lcdcs2

Post here the output from the serial port and the OS version you have.

That would help to identify the chip inside the LCD.


Regards

[dpeddi]

Hello,

I got the keyboard.

Instead connecting an Arduino to analyze the protocol, I used the 16 bit logic analyser of my hantek 6022bl.

IMG-20220912-WA0005.jpg (107.49 KiB) Viewed 4707 times

IMG-20220912-WA0003.jpg (120.31 KiB) Viewed 4707 times

I was able to obtain a stream of data from the LCD bus.

The controller should be a ks0713. I don't need to implement all the display command..it should be enough to implement the set page command.

I was able to format the data with a python script and display it on the pc screen. Here is the result:
attachment=2]IMG_20220914_001518.jpg[/attachment]

VID_20220914_001536.mp4

(5 MiB) Downloaded 236 times

Next step: replicate the python script in hardware with a microcontroller.

Regards