Roland D-110 dim backlight

[logix]

Oops! I just took it for granted that it was a direct pin-pin replacement since the pin-layout looked the same and this particular LCD was suggested here, but having just compared the LCD pinouts from the D-110 service manual and the new display's PDF I see that only two of the pins are in the same places!!!

Here's a connection table I've written, based on the above information (pin numbers in red means a difference from the original connection):


Assuming I can open up the pin-header (the end which plugs into the D-110 circuit board) of the original cable (which I've now soldered to the new LCD) I hope I can just cross the cables so I get the signal pins right, then snap the header on again. Is it possible I've already fried the new display by using the old connection pinout?

By the way, seeing that on the original display's pins 1 (+5V) and 3 (RS: Register select) were connected together, which did not mean that +5V was connected to V0 (operating voltage for LCD), should I now connect together pins 1 (+5V) and pin 4 (RS) instead, then leave pin 3 (V0) unconnected to +5 contrary to what was earlier presumed?

[jxalex]

well, i cant see that image. that site is full of advertisements but no image. there really must be some way to link pictures inside the forum so it would be visible...? Atleast it should be much simpler page, which should be possible to download directly with wget or operating with atleast 5..15 year old browser too.

the display will be fried if you have applied reverse polarity of the main power voltage.

By the way, seeing that on the original display's pins 1 (+5V) and 3 (RS: Register select) were connected together, which did not mean that +5V was connected to V0 (operating voltage for LCD), should I now connect together pins 1 (+5V) and pin 4 (RS) instead, then leave pin 3 (V0) unconnected to +5 contrary to what was earlier presumed?

RS?
well I do not understand. Since do not see that schematic what you drawed due to that picture hosting site.
The Operating voltage should be variable ( perhaps that new LCD needs different operating voltage to be visible than old one). At first just check that the ground and main +5V are on the right places and make that voltage for contrast variable with a external pot, just for testing purpose, and got the backlight working. Then its more convenient to trace the logic signals.

[logix]

Huh? No picture?
My posting looks fine here (Firefox), and also in another browser (Safari) both with and without logging in to this forum. The direct image link is here, but for some reason it doesn't just show that picture but it's surrounded by other photos and Tinypic info. Maybe that's what you were referring to when you said advertisements? In my posting however the image is shown within the posting, without any ads.

In any case this is what this forum has chosen for uploading images (I seem to recall you uploaded images directly to the forum in the past though), so there's not much I can do about it except try to upload it again here:


Did all my previous postings with images also have problems?

Looking at my pinout comparison I see that +5V and GND were applied to the same pins as intended, so that's fine, but I also shorted pins 1 and 3 (as with the original display) which means that I've also applied +5V to the display's V0 pin. But according to the new display's PDF that should be fine as well, because it explains it to be "Operating voltage for LCD" while pin 3 of the old display was "Data/instruction register select".

I'll see if I can disassemble the existing connector and re-route the individual wires of the IDC cable so the signals go to the right places, or else I'll have to order a new cable.

[jxalex]

THank You, NOW I can see the picture via the direct image link.. (Using Opera 12.16).

All other images had the similar problems, Actually I do not see the image in the forum not even now. ( I read the forum without javascript as it loads a lightyear faster this way. Perhaps this)

Now about the LCD.

The pinout is really swapped out. Fortunately they did not swapped VDD and GND (pin 1 and 2).
VO and VDD to be connected together is ok as well, if thats the contrast what it should be.
I think the cable is not so much RFI sensitive, so just chopping and crossing, resoldering is ok.

Please let me know about the progress.

Hows that backlight?

[logix]

Ah! No wonder you couldn't see the images. Disabling Javascript in a browser typically gives problems like that as the core functionality of many websites are based on Javascript.

Moving on, I've successfully removed the top part of the IDC header (which plugs into the D-110 main board), and now exposing the actual connections. Using a multimeter I was however shocked to find that the pin numbers do not match. The pin numbers are written on both the old and new display PCB, so I was expecting pin 1 to go to what is marked as pin 1 on the D-110 board and so on, but instead the configuration is reversed like this:
.
This means I might have fried the new display, or not.....

If I'm not mistaken the pin numbers should match if I was to solder the 14 pin DIP connector to the other side of the display PCB, but I'm quite sure it wasn't done this way with the original display as I took pictures before disassembling. I should really order another cable/connectors to attach to the old PCB and try it again there to avoid any more confusion.

So, if the IDC cable/connector orientation is correct it just means that I can forget about the numbering on the display PCB and instead take note of the signals coming from the D-110's CN1 connector, then attach them accordingly. Of course this also means that the D-110 original display pinout in the service manual is meaningless! I just hope the new display's pin labelling is correct.

Who knew replacing the display should be so complicated? Does anyone have any more information on the pinout of the original display? There seems to be very little information on the DM029Z-5BL7 to be found online. Perhaps they were made specifically for this particular synth and weren't standard parts.

[jxalex]

(well. With javascript the site loads too long time. Thats why I disable it. Disabled javascript does not affect the messaging function. SO, needless in other words, if the direct links to pictures are enough and much simpler. )



get the backlight to work at first, so you see better the characters.

You still have the old display, which is not fried. Right?

It is not sure if you have or have not fried the new display, so get the voltage power pins right at first.

[logix]

Good to hear you're able to see the photos now.
I checked the image links in my postings, and they're all direct links so you should be able to see all my images in this thread.

Yes, I still have the old display, but with the cable removed (soldered to the new display).
I've ordered some new cables/connectors from eBay, so in a few weeks time I will be able to try out and compare both displays. In the meantime I hope to clear up all the confusion with the connection pinouts.
On that note I came across something interested when I searched for "Roland D-110 LCD" on Youtube. Check out the comments to this and this video! They both confirm my findings that each row of pins on the LCD are swapped (i.e. 1 and 2, 3 and 4 etc). I assume they mean in comparison to the pinout numbering on the LCD displays (both my old and new one has the same placement/numbering of the connection pins on the PCB).
This means that I've probably fried the new LCD, because I checked CN1 (LCD connector on the D-110 circuit board) and the voltage polarity is correct according to the schematic (pin 1 marking on the PCB is +5V and pin 2 is GND). I'm not sure how to check the rest of the signals, but at least this confirms that I've applied the reverse polarity. This is assuming that the pinout in the new LCD documentation is correct.

About the backlight: given the IMHO confusing instructions in the new LCD documentation I haven't yet dared to apply power to it, but I think they might mean that there are connection pair options: one for attaching +5V (meaning there's a resistor to pass through on the LCD circuit board), and another connection which goes directly to the LED backlight with the correct power (in the old days this was something like 2V or so IIRC). I'm going to take a closer look at the circuit traces and I think it might be quite harmless to test it with say a 1.5V battery just to see if it glows.

To conclude all my talk ..... I really would like to hear from someone who has successfully replaced their D-110 LCD in regards to the connection pinout.
Also, if my new LCD turns out to be fried, are there compatible LCDs with a pure green LED backlight (like the original LCD)? The one I ordered is yellow/green and I couldn't find any green version at that site with the same specs.

UPDATE: Robber1956, I see you posted the pinouts earlier for a different display. Is that pin swapping in relation to the pinouts of the original display (in the D-110 service manual), meaning that the pin numbering/signal description of the CN1 connector (see below) is correct?

[logix]

OK, enough talk



So swapping the pins (1>2, 2>1 etc) seems to make it work. Also the backlight lights up without any separate connection (unlike the original LCD which has a cable which goes to a 2-pin connector on the D-110 PCB).
I assume I damaged part of the display when I connected it directly using the old cable (switching the polarity among other things). I tried connecting pin 1 (+5V) and 3 (V0 -operating voltage for LCD, which is the LCD contrast I think) together as with the original display, but it made no difference.

So it appears I need to get myself a new LCD, make a new cable and this time flip it over to opposite side of the display PCB (front instead of back) which should effectively flip the pins (so I don't need to resort to the ugly trick in the photo above).
Not a total success, but at least some progress

[Robber1956]

UPDATE: Robber1956, I see you posted the pinouts earlier for a different display. Is that pin swapping in relation to the pinouts of the original display (in the D-110 service manual), meaning that the pin numbering/signal description of the CN1 connector (see below) is correct?

Hi, yes it is.

But the e spec from EastRising ERM 1602-2.1 series is different. For instance, the original pin layout shows pin 7 is DB1 while ERM 2.1 says pin 7 is DB0 and pin 8 is DB1, pin 9 is DB2 where is was DB3 with the original LCD as if it's reorganized to match "normal" numbering on a everyday 1602 lCD with 16 pinholes in a row without twisting conductors.

And yes, pin number one is not where the traced part of the flatcable which tells it is conductor '1' is going. It's going straight to pin 2 on the PCB. I just got my lcd's so I know now what the right procedure is...i hope. To bad you just can't switch the whole connector in one go. "Mirroring" by putting the connector to the front side doesn't give problems with the remaining space between connector and front panel? I didn't open my "spare" D110 yet.

Blew up already 1 lcd (out of 6) backlight led by too high voltage from my power supply. Wrong move, 7 volt and it was gone. Ordered the 5 volt lcd. I wonder if it's the right one. Backlight was shining bright on anode and cathode already with 2.7 volt.

[Robber1956]

Pin 1 and 2 are the same as original DM029Z LCD.
The rest is: ERM 2.1/DM029Z-3/4-4/3-5/6-6/5-7/8-8/7-9/10-10/9...13/14-14/13.
Then you'll get the digits.

[logix]

This is getting confusing.
Are you sure about pins 1 and 2? I had it connected like the old display first but got no results, but when I flipped the rows (1 becomes 2, 2 becomes 1, 3 becomes 4 etc) all of a sudden the backlight worked and black boxes at least showed up on the LCD.
I need to recheck those irregular connections again as I concluded the flipped connector was the way to go.

I just noticed another problem (with the ERM1602-2.1):



That's the new LCD on the left and the original one on the right
The mounting holes don't match as the new one has a shorter spacing. You said earlier that you used the 1602a (is this the same as a plain "1602" without the "a" as I can't seem to find the "a" version anywhere?), and that it really didn't fit but you made it work with some tape. Were the mounting holes different on that one as well?

[Robber1956]

You got it right the first time

[quote="logix"]Oops! I just took it for granted that it was a direct pin-pin replacement since the pin-layout looked the same and this particular LCD was suggested here, but having just compared the LCD pinouts from the D-110 service manual and the new display's PDF I see that only two of the pins are in the same places!!!

Here's a connection table I've written, based on the above information (pin numbers in red means a difference from the original connection):



and backlight also working.


could only use just one little screw top right.
I would be satisfied with this and the connectorblock on the other side to prevent the LCD bending inwards but the position behind the front panel was not ideal. Too far to the left ands too high. Still readable though.

Mounting holes 1602A are further apart and holes instead of gaps.




The 1602A PCB doesn't even fit whitin the frame but ON the rim of the inner frame. Therefore taping is also used as insulation because of the row of pinholes on top of the PCB. Otherwise these could make contact with the alu frame inside the D110. I didn't like this solution because the rather sharp soldering points might penetrate the tape and cause short circuit. I used three layers of insulationtape, but putting the LCD in the right place is easy this way.
I'm trying to find a way how to mount the new display in the frame but it's not so easy if you don't want to mod everything to make it fit. Especialy how to centre the LCD in the right position behind the front panel. The trick is always how to solve these things without messing everything up.

[logix]

I agree -I prefer modifications that will let me go back to the original setup if I like.
I just ordered a couple of green backlight 1602-2.1 displays as well as a new yellow/green backlit one from EastRising (Buydisplay.com) so it can look like the original one, only with a hopefully brighter backlight.
I checked the placement and although I haven't actually tried it, I think mounting a 14 pin IDC-header connector on the front of the display PCB will work out fine.

Maybe I've misunderstood what you're saying, but you're telling me that with the 1602-2.1 I should flip all the connector rows with that original cable EXCEPT pins 1 and 2? How can it be that I'm now getting the display to show and have a backlight with pins 1 and 2 reversed?

[jxalex]

Here comes the the moral that buying does not solve always the troubles with a blind belief to seller solutions. But we buy again, huh?!

so much trouble becouse to get brighter backlight. I gave the complete recipe for that and why are you completely ignoring that? --
A just increase the current for the LEDs
OR
B. change the backlight element, leave the module intact!

Also if you have several backlights then go ahead, then just change the backlight element, not entire module.
YOU HAVE THE WORKING OLD LCD MODULE. SO, solder back the cable, and it works, add the new backlight, all done. you have everything already and no need for additional shopping!
ALso just changing out the backlight behind the element is not so much work, the LCD still gets back correctly in its place with the rubber conductors to glass and no need to change the all unit altogether.

I think that analyzing must be done before buying anything at all since I got the backlight bright without buying anything.


I gave the entire recipe already, but it seems I run out of oxygen before You understand.

[logix]

I gave the entire recipe already, but it seems I run out of oxygen before You understand.

Sorry if I appeared to ignore your information, which I didn't.
Lots of useful info, but I decided to replace my display instead -if my original display gets damaged there's a chance my D-110 won't have a working display at all
I'm thinking that increasing the voltage for the LEDs will likely burn them out after a while, and although I looked into removing the backlight I see it's not a straightforward process since it's buried underneath the LCD. I've opened up LCD assemblies in the past only to result in some missing characters because the pressure contacts don't work like before. But maybe the technology for this has changed since then....

Your idea of changing the individual LEDs of the backlight is interesting. Once I get at least one LCD working for my D-110 I want to check that out. You previously mentioned that there are usually 36 LEDs inside a backlight, and that they connect to 5V. Is there a resistor inside the backlight "box" to limit the voltage, or is that on the display circuit board?

By the way, if anyone else is interested in getting replacement displays with a green backlight (not yellow-green), the model to ask for from Buydisplay.com is ERM1602FG-2.1. You need to contact them by mail (see below) and I paid US$ 3.18 for each plus shipping (ask for "epacket" for regular shipping if you don't want to pay many times that with DHL). They told me it would be compatible with the ERM1602SYG-2.1 that I already have.



I'm currently awaiting new connectors and IDC cables, so I should be able to get the original display working again, and hopefully understand how to get the new 1602-2.1 display working as well, using a proper cable this time.