Replacing broken LCD Display on Roland CX-12 Vinyl cutter - Help needed.

Other Hardware Displays
1

Hi peeps.

I need you help. I am the lucky owner of an Roland CX-12 Vinyl cutter. As i don't use it much at the moment, it's on permanently loan to the local hackerspace.

Unfortunately someone dropped a heavy object on the front of it, and cracked the LCD-glass :cry:

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I have identified the genuine 16x1 LCD display as being a model RCD2122 from ROHM. The nearest information i can find is this datasheet, which is for a RCM2122: Datasheet

Unfortunately, the display is pretty esoteric, and finding a replacement is not possible, so i had to turn to replacing it, whatever that means hardware-wise.

The pinout of the display is written on the interface-board and is a follows:

D7
D6
D5
D4
D3
D2
D1
D0
ELCD
A2
A1
VO
VCC
GND

Hmm, A2, A1 - Eeeek - it doesn't sound like standard Hitachi, while it looks to be, with it's 14-pin interface.

First, i tried replacing it with an old 1x16 Sharp LCD i had in stock. It is using the old genuine Hitachi HD44780-controller. I wired it one-to-one like you would with a HD44780-display. Powered on, and lo and behold, there is something on the display, but not what i expected :frowning:

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It's supposed to say "Roland DG Corp."

When booted, it's supposed to say "SETUP > ENTER", but it looks like this:

2402×1338 878 KB

Hmm, that's rather strange - It's like chars is missing, and the right part of the display isn't even initialized.

Now i got thinking, there is something weird regarding the HD44780 regarding the memory mapping over different sizes of displays. I tried attaching a modern 16x2 display and it's the new type with a black "blob" on the back - i guess the controller is the KS0066 or a similar clone.

Now the unit powers up like this:

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Hmm, "RlndDGCor." - Now display addressing is working correct, but characters is dropped during transfer.

The setup menu which should say "SETUP > ENTER" now says "STP > ETEETER"

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For kicks i tried attaching a 1K pullup/down (both tried) on RS, RW, EN-pins in succession - it changed the written text on display a bit in some configrations, but not much.

I am going to whip out the logic analyzer next, and have a look on what's actually happening, because i can't figure it out right now.

Now, what is happening ? Any good ideas for stuff to try ?

// Per.

2

Here are some observations, in no specific order, that may help.

I found this on another ROHM datasheet - I'm not sure what significance it has:

RCD: Liquid crystal display element
RCM: Liquid crystal display module

Your RCM2122 data sheet is very similar to that of the Hitachi HD44780U. The big difference is in the DDRAM Address section where, with this device, the addressing mode can apparently be changed.

If you follow the LCD Addressing link at http://web.alfredstate.edu/weimandn and scroll down to the information about the 16x1 displays you will find some background information about these two addressing modes.

The 'old 1x16 Sharp LCD' that you tried appears to be internally configured as an 8x2 which would have a memory map identified as 'Addressing mode 2 (A=1)' on the RCM2122 data sheet. I suspect that your original (broken) display had the other memory map which is why the 16x2 display that you tried could display more than 8 characters.

Your pinout list has only 13 pins identified. I assume that D0 belongs in there above ELCD.

My guess is that ELCD corresponds to the E (Enable) pin. If not you wouldn't see any characters on the display and certainly not your almost correct 'SETUP > ENTER' display.

This leaves A2 corresponding to R/W and A1 corresponding to RS. This probably isn't exactly correct since your display is missing alternate characters.

Perhaps the ability to read from the controller has been disabled and pin 5 (A2) is being used to choose the memory map. Your logic analyzer may shed some light on this.

Don

3

Don, thanks for chiming in. Yep i meant to write D0 in the pinout list, but somehow missed it. It's fixed now.

I think you are correct in your observations - It's frustrating to be THAT close and still not have it working :frowning:

I'll have a look with the Logic Analyser one of the days, then i'll see what is happening.

// Per.

4

Hi Zapro, did you manage to get a replacement screen. I've been trying to find a replacement screen so I can mess around with adding a backlight for years.

Cheers

5

gonzocrazy:
Hi Zapro, did you manage to get a replacement screen. I've been trying to find a replacement screen so I can mess around with adding a backlight for years.

Hi. I succumbed and ordered a genuine part. It was 90 Euro, so not so "fun" as hacking another in. I did not have the time to make it work otherwise.

Backlight is no problem. You just remove ONLY the back mirror foil on the display and hot-glue a backlight unit from another LCD, this is what i have done on mine.

// Per.

6

Hello, please a link where I can order the original spare part. LCD Display CX-24 ROHM RCD2122

7

Contact Roland. They should be able to get you a new one.

// Per.

8

Hey really sorry to bump a very old thread. I'm hoping to revive this so that I can troubleshoot this with the assistance of someone else. I too am the lucky owner of a Camm-1, but in the CX-24 size. Sadly, my LCD display has broken during a disassembly of the device.

I have contacted ROHM directly to get a datasheet for the 10 year old RCD2122.... but only to receive the same datasheet that OP has posted.

TLDR; does anyone with experience in 16x1 LCD displays know how this item may be replaced without spending hundreds of dollars to get one from Roland directly?

9

CostaBr33ze:
I'll mail you mine for $10. I just took apart a canon scanner and it uses the same LCD. See the attached images.

I'm pretty sure it's a different controller. Won't work.

// Per.

10

CostaBr33ze:
It's chip on glass though so the controller is part of the lcd. If the model number is the same it's the same lcd.

Does the display say the same model number?

What model of scanner did you take this from?

// Per.

11

Original

Offering
20191026_143935.jpg

20191026_143957.jpg
Does look pretty similar, but it's not just the controller; is it (unlikely) a simple text display or custom fields according to the different devices?

CostaBr33ze:
It's chip on glass though so the controller is part of the LCD. If the model number is the same it's the same LCD.

Given that, if the model number is different, it is probably a completely different display.

12

CostaBr33ze:
Same model number. Looks identical in the photos. Canon MP360. No fields just pixels; with my finger and one eye closed I count 16 pixels tall and many pixels wide.

The original display does not have pixels. It's two rows of 5x7 dot segments. First off, the cable is in the wrong position.

Second off, usually these Canon machines use another controller.

// Per.

13

CostaBr33ze:
I dunno man. I'd rather try out a $0.10 display and see if it works before forking out 90 EURO. But I'm crazy like that.

And you have removed your previous post and images.

OK, we will leave it at that then.

14

Paul__B:
And you have removed your previous post and images.

OK, we will leave it at that then.

Are you addicted to replying to comments? What possible value does your reply add to this forum? I deleted my posts because you were harassing me like a maniac. Do you do this to all new users?

15

Paul has never been accused of being diplomatic, neither have I.

By deleting your posts you have disrupted the flow of the information in the thread. This makes it much harder for others to figure out the meaning of the remaining posts. This type of behavior severely detracts from the value of the forum.

Don

16

Deletion of content that detracts from the post is also considered VANDALISM and can on occasion result in a time out or worse.

Sometimes we can get a little frustrated but don't take that too hard unless it is quite bad and then the moderators need to know !

Otherwise take some of it on the chin and keep going.

Bob.

17

Hi,

What about this topic: Moderation Guidelines && Applications for Moderators

And handling Newbies?

Jean-Marc

18

@ZinggJM

Specifically ?

I do discourage being outright nasty to them in any way whatsoever.
I do not begrudge a member making a slight mention of a noobs inability to follow instructions of going off tangent so long as they try steer a topic back to its origins also.
I do not mind when somebody suggests the OP may be in past thier experience / comfort level either.

Outright bullying will get ZERO tolerance as some long time members have found out over the last few months.

Would you like me to split this topic so we can continue the discussion elsewhere ?

Bob.

19

Blessedly, CostaBr33ze has subsequently found somewhere else to exercise his intelligence. :grinning:

Even better, we do not know where! :sunglasses:

(Actually, we do know where, but it is mostly "Adult 18+" material. :cold_sweat: )