Kurzweil K2000 Display Upgrade

The displays in the Kurzweil K2000 and K2000R use an electroluminescent (EL) back light which fades out with time making the display very hard to read. While new back light panels are available they too will in time fade. For about the same price as a new EL panel you can purchase a whole new display which has a blue LED back light which is brighter and will not fade out like an EL panel. As a bonus you will no longer need the high voltage power supply for the EL panel and it can be removed which eliminates the high pitched whine that the EL power supply makes. The major challenge in doing the display swap is that the new LED display is slightly larger and you will need to modify the K2000 front panel slightly to make the display fit properly. The display that I used in this conversion was obtained from John Ramsey

There is a PDF version of this web page that you can download.

Back light is totally dead. You need to have bright lighting to read the old display. Not nice.

Backup everything before you start!

Unplug the keyboard!

Place your keyboard face down on a soft padded surface. A folded towel works well.

Remove the 6 screws that holds the bottom on the K2000.

Remove the battery cover and the 3 AAA cells.

Lift the back off and unplug the backup battery and if installed the fan and hard drive power connectors. Now would be a good time to clean or completely remove the fan filter.

Unplug all of the connectors from the engine and audio boards. Remove the 12 screws that hold the boards down. There may be other things to do if your keyboard has other options installed. Remove the 2 boards and the aluminum plate under them.

Once the 2 circuit boards and aluminum plate have been removed you can see the display and front panel circuit board.

Remove and save the tape that holds the ribbon cables to the front panel circuit board. Remove the 4 screws that hold down the old display and remove the old display. The display window is held in around the edges by double faced tape. Carefully press the display window out from the back.

Turn the K2000 face up and remove the data entry knob (alpha wheel). Remove the nut and washer from the control shaft.

Turn the K2000 back over and remove the 8 screws that hold down the front panel circuit board. Remove the front panel circuit board.

The new display is slightly larger than the old display and the opening in the K2000 case that the display fits through must be enlarged by 3/32". (2.3mm) on each edge for the new display to fit.

The K2000 case is made of a soft plastic that is easily filed. Measure and mask off the enlarged hole with tape. Enlarge the hole with a coarse file and test fit the new display. Once the display fits use a fine file to clean up the hole. It took me about 20 minutes to do this.

Enlarged hole completed.

The Old (top) and New (bottom) Displays

Next the wires must be transferred from the old to the new display.

The old EL back light cable is reused to power the LED back light. To insure the correct polarity mark the yellow wire which goes to the 3rd pin of the connector at each end with a black marker. This wire will be soldered to hole K on the display. Solder the other yellow wire which goes to the 1st pin of the connector to hole A on the display.

Unsolder and reuse the ribbon cable or make up or buy a new cable with the same pin out and length. Solder this cable to the new display in the same orientation. Be careful to fit the connector into holes 1-20 on the display and to leave holes 21 and 22 empty.

Test fit the new display in the front panel. The face of the display bezel should be flush with the recessed lip that the display cover sits against. I needed to add 2 #6 flat washers between the display and the front panel at each screw location to move the display back for a proper fit.

Once the fit is correct mount the new display to the front panel with 4 screws.

Reinstall the front panel circuit board using the 8 screws. Reinstall the 2 pieces of tape that hold the ribbon cables to the front panel circuit board. Turn the K2000 over and reinstall the washer and nut on the shaft for the alpha wheel. Reinstall the alpha wheel.

Separate the audio circuit board from the front panel and desolder and remove the EL transformer and driver transistor Q25.

Turn over the audio circuit board and add 2 wires as shown above.

The black wire goes from the negative terminal of the large (22,000uf/16volt) electrolytic capacitor to the 3rd hole in the top row of where the EL transformer was removed.

The red wire goes from a +5 volt source to the 3rd hole in the bottom row of where the EL transformer was removed. I used pin 14 of U60 for the 5 volt source. My K2000 is a Calvin version and I am not sure if this is the same for the Janis boards.

The thin blue/green wire was some sort of factory mod and was already there before I did my mods and should be ignored.

Reinstall the aluminum Plate and both circuit boards using the 12 screws. Replug all cables except for the LED back light cable. Turn on the K2000 and check for +5 volts and the correct polarity at the back light plug.

Once you verified that the voltage and polarity are OK turn off the K2000 and plug in the back light cable.

Place a new layer of double faced tape on the back of the display cover. I used a wider band of tape than the original so that the cover would stick to display as well as the front panel.

Clean both the display face and the back of the display cover. Peel off the backing on the double faced tape and press the cover into place.

Flip the K2000 over and reconnect the fan and hard drive connectors. If you didn't clean the fan filter when you removed the cover do it now.

Reinstall the bottom cover on the K2000 and replace the 6 screws.

Reinstall the memory batteries and battery cover.

Flip the K2000 over and turn it on. It should reinitialize the memory and effects.

Reload any samples and patches and you are done!