Korg Wavestation Refurb

Overview I bought my Korg Wavestation new in 1990 as a grey import with no serial number for £1200, £400 of RRP. It was a big purchase for me back then, and my first digital synthesizer, which I used for many tracks in the early 1990’s. I loved the wave table sounds and the keyboard with after touch. I added a few sound cards, Drums and Performance 3. As my studio grew the Wavestation was rather side lined and then put in the garage for storage for 20 years, where it gathered dust and scratches.

In 2020 I dug the WS1 out to refurbish and possibly sell, but once plugged in and making sounds in the new Garden Studio I decided to keep it. I do have iWavestation on an iPad but it is not quite the same as the original in sound or play-ability. It does have the advantage of displaying the waveforms.

The Refurb My Wavestation needed a new back light, new front panel buttons, keys cleaning and some scratches on the screen removed. The scratches on the panel, created during its long stay in my garage would have to stay. The component values referred to in this post are for the original Wavestation, the component numbers and values are different in the AD rack version. The disassembly of the Wavestation is a complex and lengthy process, I photographed and documented every stage. Here is a visual guide and more information on the new LED replacement process.

New White on Black Display

New LED Display The large 64 x 240 LCD is best replaced with a modern LED display which is nearly plug compatible, it lasts longer and enables the noisy inverter to be removed. I bought my white on black display from BuyDisplay with the pin connector fitted. The display is connected to a 20 pin-header on the main PCB at CH13A, I made a new 20-pin ribbon cable with sockets to connect to the new display. I reused the old 2-wire LCD EL power cable that goes to CN11A (CN4 on early models) on the PSU board, with a minor change to the board (detailed below).

Here is a list of the changes needed:

• Pins 19, 20, 21, 22 should be removed or cut from the header on the LED display.
• Pin 19 needs to be connected to Pin 3 (+5V) using thin wire to ensure the right font is used.
• Add a 3K9 resistor between Pin 2 and Pin 4 to modify the contrast voltage.
• Connect the A and K terminals on the back of the display to the old LCD back light cable.
• Remove EL transformer (T2) from the PSU board.
• Remove C28, C29, R17 and R18 from the PSU board as they are not needed.
• Add a 100R resistor between +V pad of C28 to where Pin 4 of T2 was.
• Replace R17 with 6K8 and R16 with 3K9 resistors, to get the contrast correct.
• I replaced C30 on the PSU board with a modern MLCC 100nF capacitor, as preventative maintenance.

Once all the modifications are done and checked, the Wavestation can be reassembled, and powered on. The display works very well, although not exactly a black background it is very close, and it makes using the Wavestation a joy.

EX Upgrade The Wavestation of 1990 can be upgraded to EX capability by installing 4 additional wave ROM’s (total of 2MB) and the EX OS which is at version 3.19. The EX upgrade was more about drums and piano, but there are additional Prophet VS waves in there as well. A total of 119 waves were added and 8 more digital effects added, most of the new wave sequences are rhythmic.

OS ROM 3.19  The operating system is contained on two NEC D27C1000A-12 ROM chips (the Wavestation AD uses the -15) at IC18 and IC19, they together hold 256 Kbytes of data. They have a slightly different pin out to modern equivalents like the MBM27C1000A-15Z, which need pins 2 and 24  swapped during programming. I have used the original chip type to avoid complications. The OS binary is available from the Synth ROM Database.

Wave ROM The wave data is held in four 512 Kbyte Mask ROM’s (2 Fujitsu and 2 NEC) that have been encoded at the factor, with a total of 2MB. We need to use EPROM’s that we can burn with the wave data and I have used ST M27C4001-12F1 chips encode with the wave binaries available from the Synth ROM Database. Four 32-pin turned pin IC sockets were soldered onto the main board along with four 100nF 2.5 mm spaced ceramic capacitors. The four new ROM IC’s are located in the sockets as follows:

• IC2 – WS4P0
• IC3 – WS3P9
• IC4 – WS3P8
• IC5 – WS3P7

I bought the chips and had them programmed by buyicnow.com for under £50 including postage. This a a very easy and cheap way of getting the upgrade chips and sockets. The original Korg upgrade was £300 in 1992.

The Prophet VS Legacy The Wavestation is a major development of the Prophet VS from 1986 and most of it ROM waves were reused, the Wavestation added wave sequencing as well as many more waves than the VS. The 1990 Wavestation uses Prophet VS waves from 35 to 125, including bells, vocals and some traditional Piano and Bass waves.  The Wavestation documentation does not contain a description of these waves but with some detective work looking at the Poly Evolver waves which are also VS waves, its possible to add the wave descriptions, which are here Korg Wavestation – Prophet VS Wave Descriptions.

The Wavestation EX added in the Prophet VS waves 126 to 155, however the ROM memory in a VS stops at location 127, so these 30 waves are possibly from one of the six Prophet VS RAM cartridges which contain 32 waves. The VS126 to VS155 waves are visible in iWavestation but there are no descriptions.

Korg WSC-3S Cards

Patches The Wavestation comes with 3 banks of sounds, one in ROM and two in RAM. Korg produced quite a large library of patch cards as well as three PCM cards with new waves, and many professional patches were commercially released by companies in the 1990’s. A full list is here. I have a large library of sysex files stored on my PC and my personal favorite patches are loaded onto a MCR-03 RAM Card. I use the iWavestation to preview patches and then I load them up via sysex.

The Wavestation was commissioned into the studio on 8th April 2020 and replaces my S-50 in my active setup (as the W-30 has 240MB of S-50 sample banks on hard disk). The refurb has worked really well and the Wavestation now gets lots of use in creating new songs, the key is to try and avoid all the presets that have been overused in the 1990’s .