I bought this second hand about 15 years ago, and it's been in my rack since.
Feel free to make an offer or message me if interested.
The internal battery is brand-new, having been replaced in the past month.
As you can see in the photos, there's a few scratches around the edges, and the rack ears are a little bashed in the corners (thanks to the previous owner).
However, all the buttons and controls are in good condition and good working order.
Includes the user manual which is also in good condition.
I don't think I have the original box, but it will be well packaged and boxed of course.
The MKS-50 is a fantastic synth from the 80's, with some good resources on the web (such as llamamusic com/mks50) and modern hardware editors available - for example the Retroaktiv MPG50 and the DTronics DT300. I would keep it, but I'm fortunate enough to also have a Juno2 and I don't need both of them :-)
Description from vintagesynth.com: The MKS-50 is a rack-mount version of the Alpha Juno. It has the same synth engine and architecture, with some added features like 16 programmable chord memories, the ability to store velocity, volume, panning, de-tune, portamento and other similar parameters within each patch you create. The optional and highly recommended PG-300 will give you traditional slider type control of all editable tone parameters which include DCO (digitally controlled oscillators) LFO, bend, ENV, pulse, waveforms, noise, PW/PWM, high pass filter, VCF (filter) with freq/env/res/LFO/kybd, VCA envelope, chorus, and more.