Roland D-70 display replacement

(and a fix for the ‘No RAM Card <Exit>‘ message!)

Right. A project which is looooooooong overdue 🙂 replacing the display of my Roland D-70.

The Roland D-70 has a Toshiba TLX-711A LCD display which is illuminated by something called ‘EL-foil’. This is a foil which is positioned behind the LCD glass and illuminates it. The problem is that these foils don’t have a really long lifespan and they become dimmer and dimmer until the backlight is gone. As the Roland D-70 model is 30 years old. I have yet to encounter a D-70 with a working backlight.

The old EL-foils works on high voltage if I read correctly. The internal power supply of the D-70 outputs 5v to the display. To power the backlit there is a converter near the display which takes 5V DC as input and outputs 230V AC (I measured this). The converter enjoys this process so much that it emits a really annoying cheerful ‘wwwwwwwhhhhEEEEEEEEeeeeeeeeEEEEEEEEeeeeEEEEEEEE’ noise.

Replacing the display with a new LED backlit version also fixes this problem 🙂

There are other websites where people share stories on replacing these displays but they leave out so many steps that it’s not exactly a ‘how to’. The instructions I found are more like this:

As I’ve been putting this project off for a couple of years now I will try to make this into a ‘how to’ 🙂

I’m not afraid to take anything apart and I’m pretty good with a soldering iron but this is not a small job. I can fix a lot of stuff if there are clear instructions to follow but I am not a electronics whiz. I know what a resistor is. And a capacitor (sort of). But when I see ‘just remove the inverter and replace this with a basic emitter follower circuit’ I’m lost 🙂

Let’s begin! (disclaimer: do this at your own risk. There is always a chance you destroy your D-70.. and / or hurt yourself or burn your house down or have your wife yell at you when the dinner table is covered in D-70 parts when it’s almost dinner time 🙂)

Step 1: Which display to buy

The original Toshiba display has a T6963C controller. So any display with the same dimensions and a T6963C controller should work. I have found only one supplier and it’s http://www.buydisplay.com They sell this awesome replacement for around € 25,- It’s this one:

They make this display in about 10 or 12 different colors. The yellow one looks the most like the original one but I bought the black on white one. Should look cool.

Here is a link to the display (but you can also find them on eBay):

https://www.buydisplay.com/24064-lcd-240×64-t6963c-controller-module-display-compatible-ra6963

Step 2: removing the old display

This is kind of difficult. The mainboard of the D-70 is in the way and the keybed has to come out. Lots of little screws and really annoying flat cables that have to be removed.

First put the D-70 upside down (on some towels) and remove all screws from the bottom. You should now be able to lift the bottom plate.

The next step is to remove the mainboard. This is the most difficult part. There are a few gold colored screws to remove from the PCB (and don’t forget the black screws from the back of the synthesizer) but first you must remove most of the flat cables. There are 4 types of connectors involved.

This is a picture of the mainboard:

The cables you need to disconnect:

The ones that hold the flat cables going to the keybed:

You just simple lift the left and right sides of the connectors up by 1mm (carefully!) and you can pull the flat cable out.

These connectors:

They can be pulled gently and are not very difficult to undo.

Then you have these bastards:

These are the cables going to the display. They are difficult to remove. (edit June 19th 2022: I’m just fixing an other D-70 and I was mistaken. These cables come out very easily 😀 I see I removed the top part of the first connector in the pictures above. Leave it on and press down on it. You can now pull up the cable.. Doh!)

The way I got them out was using a putty knife and gently moving all pins in the same direction at once:

This technique works pretty well actually 🙂 The last connectors where these:

They look easy to remove but no matter what I tried I couldn’t get the cables out. (yes I know you are support to lift the inner white part but it wouldn’t release the cables)

I just left the cables attached and removed the mainboard with the card reader board attached to it.

Then you can remove this board which has the old display at the other side:

Step 3: prepping the new display and mainboard

Right. Now my first plan was to desolder the black flat cables from the old display and solder them to the new display. This is also the route several others took but #$%#$%#$@ these cables are not only soldered but also glued to the display:

I tried but removing these is a giant pain in the ass unfortunately. So I ordered some 20 pin IDC connectors and plugs and made a new cable:

The original cables are 9 pin and 10 pin cables. I just used a 20 pin cable and made a connector at one end that’s going in the new display. I had to splice the cable at the other end and connect all the even wires to one connector and the odd ones to the other. I removed half of the pins from those connectors to make it easier not to mess this up. It’s important to get this right so check with a multi-meter if all the connections work and you didn’t switch the connectors on the mainboard side as this would be a bad thing.

They I desoldered the old connectors from the mainboard and soldered the new IDC connectors in place (after removing 10 pins from one and 11 from the other):

Yes I damaged one pin in the middle of the 9 pin row 🙂 after soldering in the new connectors I tested for continuity and all was well.

Then I soldered the new 20 pin socket to the display which fit perfectly after a minor modification:

Be aware that the old display has 20 pins and the new display has 22 pins. Leave 21 and 22 open. They can be used to power the backlight but I used the connections on the other side of the display. Before soldering I also removed pin 1 from the connector above. This is also the case in the original display (hence the 9 vs 10 lead flat cable). Pin 1 is supposed to be connected to ground. I removed the litte cable that was soldered to pin 1 from the old display and soldered it to the new one:

After soldering the connector looks like this:

I soldered the old cable that will power the backlight to the other side of the display:

I figured that white would be the positive side going to the anode and the black wire to the cathode. I was wrong 🙂

As the new display is slighty thicker than the old display I mounted the metal brackets on top of the circuitboard so the display won’t stick out further. After that I put electrical tape on the bottom of the display as it is very close to the circuitboard it is mounted to:

I put some plastic rivets between the metal brackets and the circuitboard to create a little room and mounted the ground wire to the metal chassis with a small nut.

Now the new display is ready and the mainboard connectors are ready. The only thing left is removing the old inverter from the mainboard:

You could connect the IN and OUT terminals because the new display apparently has a built in 330 Ohm resistor but I’ve read this makes the backlight on the new display very bright. A 200 Ohm trimpot should do the trick in dimming it down a little. The smallest value I had was 500 Ohm so I used that. You could also just solder in a resistor but you’d have to experiment a little with the value to get the desired amount of backlight. Using a trimpot easily makes this adjustable with a screwdriver. This is how it looks on my board:

I used hotglue to fix the trimpot to the board because turning the center with a screwdriver could snap it right of the mainboard as it is only soldered to the mainboard with one leg.

Almost there!

I left the backlight unplugged for the first power up to see if the new display works:

YEAAAAHHHHHHHHHHHHHHHHHHHHHHH!!!!!!! IT WORKS!!!!!

It just displays ‘No RAM Card <Exit>’. I’ll get to that later.

I plugged in the power to the display’s backlight and nothing happened. Hmm. With my multimeter I figured out that there was going -5v (minus 5 volts) to the display. As the backlights are LED’s and “LED” stands for Light Emitting Diode and diode’s are picky little bastards when it comes to the direction in which the current flows I needed to swap the ground and VCC leads.

3 options: remove the mainboard and the display board and switch the wires on the display (naah..), cut the wires and solder them switched around (plausible) but I opted for the 3rd option which was removing the pins from the connector and swapping them that way.

This was pretty easy so a few minutes later I tried the D-70 again:

It works! 😎 while holding the D-70 vertically I could adjust the brightness of the display with the trimpot on the back.

If you look at the D-70 display replacement blog page from Leo Breuss, instead of just opting for a trimpot he constructed a emitter follower circuit with resistors and transistors and wires and other things so you can adjust the brightness by turning a knob of the back of your D-70.

Why? “Because I can” was his reason and that is an excellent reason because it’s the same reason why I’m changing this display 🙂

Step 4 26: finishing up the loose ends:

Right. I now have a D-70 with a working display but is says “No RAM Card <Exit>”….

Pressing EXIT about 10 times gets me to the main menu. It looks like this:

Nothing but a garbled mess. No sound from the D-70 either. The internal memory must have gone corrupt while the mainboard was disconnected. No biggie, just reload the factory data via Sysex and Bob’s your uncle. Although this is true I took me a little while to figure out how to do it. I connected the D-70 with a Roland UM-ONE USB midi adapter to my computer and send the D-70 factory data sysex file via Midi-Ox. No error’s on my computer but nothing happened on the D-70. Apparently you can press EDIT and then F5 to get into system settings and setup the MIDI transfer but every time I tried that the “No RAM Card <Exit>” message reappeared.

Long story short: switch off your D-70. Hold the NUMBER 8 button and power on.

It will display: Clear all memory. Are you sure? (Yes = ENTER)

After this it displays the Roland D-70 init animation and brought me to the main menu. Still all the patches where garbled but now I can press EDIT and F5 (system) without it displaying to ‘No RAM card (exit) message! 🙂 This somehow reset the OS so it now boots normally and all the menu’s are accessible. Great! Now press EDIT and then F5.

Set ‘Exclusive Rx’ to On and ‘Unit Number’ to 17. There is a hardware switch on the back of the D-70 to protect the internal memory. Set it to OFF and load the sysex from your computer. After this was done on my D-70 the display read “Exclusive communication Error! <Exit>” but after I rebooted the D-70 everything worked again!

Success! No all I have to do is put the bezel back on the screen and put a bunch of screws in the back of the unit. I played with the D-70 for a while and when you skip all the piano stuff the strings, basses and synth sounds are really really good 😎

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