Roland D-110 dim backlight

[logix]

Is there a way to replace the LCD-backlight of a Roland D-110?

Mine's pretty dim and having opened it up (I needed to change the internal CR-2032 battery anyway -which fortunately is placed in a battery holder) it appears that the backlight is placed behind the LCD display which in turn is attached to its PCB via conductive rubber strips. I've tried opening up those kinds before, but never again as they're almost impossible to get right!
Also, I have no idea if there's an LED backlight or an EL (Electro luminiscent) there. Perhaps I need to change the whole display module? The two ICs on its PCB are marked:

Sanyo LC7930
Oki M6222B -OIL

On the other side the PCB is marked "DMO29Z"

Does anyone know if it's possible to replace the backlight or get a new display module which will fit this synth?
Oh, and please.... no blue backlights! I guess I'm old school and want the original green colour

[jxalex]

And superbright green? well we can do it together. I have opened it and so far I saw no high voltage lines going there.

the backlight "module" is a LED array of 36 LEDs. there goes 5V to the whole module.

check that that it gets some voltage to its module edges. Mine had 4V on it and it was quite dim. You may reduce the R5, so it will get 4.5V so you get higher light output.

YOU can as well put inside 0603 or 0805 sized SMD LED elements inside the array.


My LED array is lit, but somewhat dim and I just placed a diode in parallel with R5 and got the 4.5V to that module and it is bright now.

However I may as well replace with superbright LEDs, becouse the whole array can consume 0.5A as it is with original diodes!

[logix]

Interesting findings!
I've reassembled my D-110 since posting so I won't be able to check the voltage now, but plan to open it up again if/when there is a final solution to fix the dim lights.
I don't know about changing the resistors to get a higher voltage -the chosen values are usually there for a reason and feeding higher voltages will likely shorten the lifespan of the backlight. So you've confirmed that the display is LED backlit and not something else?

Looking at the attached photos there's some white plastic underneath the LCD display, seen from each end. Is this a complete "backlight module" which is replaceable? What I worry the most about of course is putting the LCD back on as the "pressure contact strips" are quite tricky to get right IMHO.

[Robber1956]

I recently changed the LCD for a blue 1602a LCD and to make things worse the MIDI message indicator for a red one .



(used flashlight because the display is far too bright for a nice picture without the reflection)

The 1602a display I used doesn't really fit, but with some tape you can place it neatly behind the front panel. Just make sure that the 16 display connectors or any of the PCB parts of the display don't touch the D110 frame by using some extra tape.
Wiring of the 1602a is 2>1/1>2/4>3/3>4/---14>13/13>14, 15 A/16K.

A better option for you old school purists is to get a ERM1602SYG-2.1LCD display:

http://www.buydisplay.com/default/chara ... lack-on-yg

Took me some time to find this and I had the 1602a already laying around but I ordered a couple 1602 2.1 displays for my other D110, a BOSS SE-50 and perhaps the YamahaTX81z (didn't check that one yet) because they will fit in the D110 and BOSS without using tape and the wiring, due to the PCB lay out with 14 connectors on the left and and the A and K on the right is in the same order as shown above and thus as the original display the DMO29Z.



So you can desolder the whole cable and use it for the new display. Beware, I didn't receive the new displays yet but I'm 99% sure it's gonna work this way. Please check first for yourself.

[Robber1956]

Also pin 1 and 3 are bridged as can be seen on the second picture form logix. Why I don't know yet. Everything is fine with the 1602A. Perhaps one should do the same with the ERM1602SYG-2.1.

Another thing is the firmware, latest for the D110 is 1.13
The benefits of upgrades are not always spectacular afaik, but editing the D110 (and all my other synths, often using an Atari ST) requires stable and well developed in sync equipment.

So I bought a eprom burner (or eeprom):

http://www.ebay.nl/itm/141701435348?_tr ... EBIDX%3AIT

some empty eproms

http://www.ebay.nl/itm/OTP-PROM-AT27C25 ... Swm8VUtXmS

and downloaded the latest firmware:

http://llamamusic.com/d110/ROM_IC_Bug_Fixes.html

and presto, all up to date.

[logix]

Thanks!
So if I've understood you correctly the ERM1602SYG-2.1 is the one to get if I want a direct replacement (electrically and mechanically) without any need for modifications or extra hassle (except soldering the old D-110 display cable in the empty connection pins of the new one)?

I didn't notice the bridging between pins 1 and 3 as you mentioned, but according to the display's datasheet (found from the same seller but on eBay) they have the following descriptions:

pin 1 VDD (Logic power supply)
pin 2 VSS (Ground, 0V)
pin 3 VO (operating voltage for LCD)

I have no idea what "operating voltage for LCD" means though -can you figure it out?
Update: I read further down in the 1602-2.1 datasheet (on page 20, under "7.6 precautions for operation") where it says: "Viewing angle varies with the change of liquid crystal driving voltage (VO) Adjust VO to show the best contrast"
On page 9 it says VO ranges between 4.5V - 5.1V (typically 4.8V) and pin 1 (VDD) appears to be in the range of 4.8V - 5.2V (typically 5.0V) which leads me guessing that Roland could probably have put a trimpot between +5V and pin 3 but didn't and decided to feed it just the same voltage as for driving the display itself.

It's cool that you're using Atari ST computers -same here! My D-110 EPROM version is 1.06 -do you think I still need to update it? Alas I don't have an EPROM programmer and most of that stuff is Windows-only (I'm on a Mac) so I should probably just see if someone sells them on eBay already programmed (a quick look shows me that they are available). Did you notice any difference after you upgraded the EPROM firmware?

[Robber1956]

Hi,

thanks for referring to the data sheet. The the resistor's colour code (white/black/brown/gold) says, according to an online calculator like this:

http://www.digikey.com/en/resources/con ... ode-4-band

it's a 900 ohm resistor and yes it is somehow to fix the contrast (It doesn't change the luminous intensity of the backlight). If you put a trimpot in between you can change the contrast of the digits. What happens is that (from a certain angle) you won't or will see the pixel blocks. So "operating voltage for LCD" means the voltage that sets the contrast just as you figured out yourself in the update.

The D110 has no trimpot inside that can change the contrast but it may be possible to add one and put it there where the 900-Ohm resistor sits.
For instance, in a Yamaha SPX90/90II etc. there is one inside on the PSU board and a DX100 has a contrast control at the back. So yes, I think you can swap the modules without any extra modification. Only thing is if desoldering is easier than just cutting and stripping the wires and solder them directly on the module like I did with the 1602A display.

I started with firmware 1.10 for both d110's. I was just trying to change parameters like the VCF real time through sysex recorded in a sequence to bypass the VCF envelope. Couldn't get it done so I thougt perhaps I can do it with the upgrade, but is seems that I'm overestimating the prospects here. Still...would be nice if possible. Anyway, I can always use an external filter.

http://llamamusic.com/d110/ROM_IC_Bug_Fixes.html

[logix]

I just ordered a (yellow/green backlight version) ERM1602SYG-2.1 through the "Buydisplay" eBay store costing me a grand total of US$ 5.13 including shipping. Not bad if it works

I think I'll try to solder a small trimmer between pins 1 and 3 so I can experiment with different contrast settings. I'm not so happy about doing modifications which damage the original design of synths, so I won't drill a hole or anything for it, but adjust it before I completely re-assemble the D-110.

Desoldering the multi-pin connector with cable from the existing display is a good idea, instead of making a new cable. I'm in the process of repairing several synths at the moment (replacing worn out buttons, new internal batteries etc.) so the less work the better -and more time for actually using them to make music

Adjusting a synth's VCF in realtime via a sequencer is a cool thing to do. I've done it a lot with my Roland JX-8P where I have the PG-800 programmer attached and the sequencer records anything I adjust there. Too bad it isn't possible with the D-110, but I guess each synth has its strengths and weaknesses, so it's a matter of choosing the right synth for what you want to do.

[jxalex]

I

Looking at the attached photos there's some white plastic underneath the LCD display, seen from each end. Is this a complete "backlight module" which is replaceable? What I worry the most about of course is putting the LCD back on as the "pressure contact strips" are quite tricky to get right IMHO.

that "white plastic" underneath you can tear off the top layer and You see there are inside ca 36 LEDS.
For the module pins go +4.5.. 5V THe pressure contact strips just set back to the same positions (or just keep them at the place and just remove the LCD and put back it later.

[logix]

I'll take a look when I get the new display and disassemble the D-110 again.
It's strange that the LEDs have become dim when I think about it. Don't LEDs just die instead of getting fainter as time goes by? I believe CCFL or EL backlighting gets dimmer by age though. Perhaps the LCD display itself is getting "bad".

Is it possible to buy replacement LED backlight modules for displays like this? I don't see myself trying to solder 36 SMD LEDs inside that white plastic "Box"

[jxalex]

Yes, its wise to experiment when You have already the replacement module arrived. It would still be good to know if the same tweaks which I used help others too

Check how much voltage goes to the LED display ? It has to be 4.5...5V.
Its totally ok, if YOu just now connect parallel with that R5 resistor another 50 ohm resistor and see it gets brighter or just connect the DIODE So you get 4.5V

The backlight module is similar in construction to Korg Triton Rack, but smaller.

So far yes, AFAIK leds dont get dim or die. Also, I think why it was not done for 12V (as diodes could be coupled in series and it will consume less power.

LED backlight modules. I can do it for You in the old module. I need just LEDs and the old module. I solder almost every day (when not writing posts or music) the SMD details.

About that D110 module (I got it just recently) I have another thought that instead of using the card I use memory 256kBit circuit as it has to me sense to use memory card only if I have several same units.

[logix]

So I received my ERM1602SYG-2.1 a few days ago and decided to give it a go today.

The pinout was the same for both old and new displays (as pointed out earlier), so I just unsoldered the connector and soldered it back on to the new display. I wasn't sure about the polarity of the LED backlight compared to the old display, so I left it alone.
When powering up nothing happened! I was expecting to see characters on the display (though no backlight), but nothing....
Next I soldered pins 1 and 3 together (as with the old display) but again nothing. When I have more time I'll trace the PCB and find out where I can check for the various voltages as I didn't do now.

So what could be wrong? Have I bricked my D-110?

[jxalex]

dont panic. its unlikely that you have bricked it, becouse the LCD module and backlight has life of its own.

just begin to check the supply voltages from power supply at first (in case if you caused 5V short circuit) and just get the backlight in working order.

[logix]

My D-110 appears to work -I managed to get the demo songs to play, navigating "in the blind" without a display, so that's a good sign!
(the manual is a bit misleading though: in play mode (just power the unit up) you have to press (and hold) ENTER first, then press EDIT and finally release both buttons. Then press ENTER which will start playing the first demo song).

OK, I measured the various voltages (first from the three voltage regulators where the PCB marks the appropriate pins with +5V, +15V and -15V, then all the measuring points elsewhere on the PCB where voltages were marked. I got +5.11V, +15.23V and -14.75. Are they within range of what's OK?

So next I checked the connector for malfunctions and it appears to connect fine to the LCD. One thought comes to mind.... could it be that some LCD displays actually don't display anything until the backlight is turned on? The original D-110 LCD worked fine without the backlight (though harder to read of course), but since the connections seem fine I'm wondering if this is where the problem lies. OK, so next let's move on to the actual backlight...

I checked the voltage of the D-110 backlight connectors (a white 2-pin connector next to IC10) and it measures +5.085V which is probably within specs.
So I really should get the new backlight powered up, but herein lies the confusion. Just what exactly does it mean where it says that pins 15 and 16 (the LED backlight pins) shouldn't be connected if pins A and K of the backlight are connected to the power supply, and R7 & R8 should be removed if pins 15 and 16 are connected to the power supply? The display PCB seems to have two unjoined soldering pads next to pin 15, but I'm confused and don't know what they mean.

[jxalex]

the backlight has nothing to do with LCD itself. it is just poor visibility without backlight. so these 2 have totally different lives.


what popped into my head is that the new LCD module is not compatible to old one, if You swapped out the LCD module as well, and not just backlight.


to swap the backlight you do not need to swap out the whole LCD module.

I suggest to put the connector to the old LCD module cable as well (so you can try with old and new by just unplugging and plugging the other). For connectors they do not have to be exact. Just sacrificing an old IDE 40PIN connector will do (you have to chop the one edge though to get it shorter).