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Korg Wavestation Power Supply

A replacement SMPS carrier board for the Korg Wavestation.


Rev. III Installed in a WS-1 with an LCD mod

A Korg Wavestation power supply carrier board, intended as a complete replacement power supply built around the readily-available MEAN WELL RPT-60B.

Please note: This board is not designed for Wavestation keyboards that still use the original electro-luminescent display. Your wavestation must be using a display like those sold by saint_baz on eBay. I don’t know or work with the guy, but I’ve bought two of his Wavestation displays, and they’re fantastic. He’ll also provide clear instructions on installation if you ask for them.

If that's no good, or you really want to keep the display - alternatives options to this board are listed below.

Outside of powering the original display’s inverter, both power board models (KLM-1421 and KLM-1422) take mains input and deliver common voltages over five-pin JST connectors. Contemporary LCD displays take their power from the 5v digital rails, making for a simpler power situation.

This board is not a commercial product - the boards I’ve had made are non-RoHS, non-UKCA, non-CE, and are best served as a basis for your own design.

I’m happy to sell you one, as a reference board for a nominal cost - but I don’t do support, and using the board for anything more than a reference is at the buyer’s risk.

I currently have four rev.I boards, five rev.II boards, and four rev.III boards sitting spare. All boards work, and are priced as follows, and are not inclusive of their £3.65 postage.

Of course, you can also get your own made up by JLCPCB.

PCB Layout


Wavestation WS-1 Carrier Board Rev.III

Bill of Materials

In order to assemble this board, you’ll need to have on hand:

You’ll also need:

Lastly, you may want:

Changelog

Revision 1 Issues

Revision 2 Changes

You can find them in a few places. Sound to Parts in France sell them individually (and with markup). AliExpress is a cheap option if you’re willing to wait for China shipping. If you’re buying elsewhere - the switch is 45mm long, arse-end to tip (unlatched). The two live pins are 8mm apart, centre-to-centre. The M3 holes on the wings are 20mm apart, centre-to-centre.

Please note: It’s very hard to find a matching mounting bracket. For both the old and new switches. Your best best it to re-use the bracket on your existing switch, or construct one yourself. Or, well, you know. Just epoxy the switch to the board and maybe resolder the legs when the joint cracks in 20 years.

Revision 3 Changes

I will eventually upload all KiCad sources and a bill of materials to my codeberg. After that, you're on your own (to do your due diligence).

Alternatives

If you’re not comfortable soldering, haven’t replaced the ELD with an LCD, or simply don’t wish to deviate from official Korg parts - there are two boards made for the Wavestation:

  1. The 230/240v KLM-1422 board that shipped with European/British Wavestations.
  2. The 100/117v KLM-1421 board that shipped with Japanese/American Wavestations.

The former is certainly the best choice, but the latter is far more commonly available on the parts market. In order to use a 100/117v KLM-1421 you’ll need a stepdown transformer.

The Wavestation has sufficient space to fit a small toroidal transformer provided you drill a hole in the bottom mounting plate. This is what I used prior to making this carrier board.

Do be aware that bare transformers push a higher voltage when under insufficient load, and RS/Mouser/CPC/Farnell/etc don’t sell a toroidal that is both small enough to fit, and configured to hit the 100-117v range the KLM-1421 expects. The smallest 230v→115v transformer they offer outputs ~130v with the Wavestation drawing power. A Wavestation with the original ELD may be enough to drag it down, but I can’t confirm this.

Instead, I recommend reaching out to Airlink Transformers. They’re based in England, and for a little under £50, they’ll make you a potted 30VA 240v → 100v toroidal in the smallest package possible.

If you give them part number TT:008695 and specify the above VA/Voltages, they should know exactly what to do. Their transformer outputs ~110v from my home’s ~240v input, when the Wavestation is on, and can be hooked up with WAGO lever splicing connectors.

The downside of this approach (aside from adding a hole to your bottom plate) is that the transformer sits prior to the power switch, and as such will be powered even when the Wavestation is off.

I replaced it for that reason - but provided you don’t leave the wall socket turned on eternally, it is a worthwhile consideration, and far less involved a task.

Or, presuming you do have a power board, and it’s just acting up (usually illustrated by phantom button-presses, or other misbehaviour like the top octave of your Wavestation buggering off every now and then), you can likely get back on track with some servicing.

They [the boards] are not that complex - they really are the prototypical 1990’s switching power supply, and are built entirely with through-hole components. Any dedicated repair shop should be able to get it back into action for a reasonable cost.

Korg applied liberal amounts of silicone glue on the power boards I’ve seen, which is both a sensible precaution against impacts, heat, and arcing - but also occasionally a tremendous pain in the arse when the job would otherwise be a trivial recap.

I don’t offer power board servicing for this reason, but many others do. And while they’re at it, they can also check out the capacitors on the mainboard and IO board. I’ve yet to see the sort of capacitor issues found on other synthesisers like Roland’s XP range, but catching these sorts of issues early saves a lot of time and money.

©MMXXVI Patrick
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