Vintage Synth Explorer Forums

Hi!
Today I found my dads old MKS-30, and decided to try it out.

The sounds were great, the midi worked, but the synth skipped variated notes. I saw no sence in the "skipping", it was no pattern, and it skipped even though I just played that one note.

Have anyone else got the same problem? What to do?

I know it's a great synth, so I really want to have it up running..!

The MKS-30 has the same voice chips used in the Juno 106 which is infamous for losing voices over the years. One or more of these chips has gone bad.

Synth Spa is an online vendor who can do the repairs for you...$170 with free shipping both ways. They also do full overhauls for $250.

I'm sure Rhino will come along soon to explain other options for DIY repairs.

Welcome to the board!
Turn the synth off, then on. Play one note at a time in a scale (any). Keep track of the dead notes. If it skips one out of six, you have a dead voice. Since you hear neither oscillator, the fault is likely in the filter. The filter chips are quite robust for the era, so I'd start checking with the de-multiplexer chip and move from there.
If this post confuses you, take it to a tech. If it skips more than two out of six, or is random, then you have deeper troubles. Still quite worth fixing.

rhino wrote:Welcome to the board!
Turn the synth off, then on. Play one note at a time in a scale (any). Keep track of the dead notes. If it skips one out of six, you have a dead voice. Since you hear neither oscillator, the fault is likely in the filter. The filter chips are quite robust for the era, so I'd start checking with the de-multiplexer chip and move from there.

No, the MKS-30 has the same 80017A VCF/VCA chips as the Juno-106. Definitely not "robust"...

My bad. Misled by this in VSE: "The MKS-30 is a MIDI rack module version of the JX-3P..."

Well, it is the rack version of the JX3P but it uses the Juno voice chips...typical Roland design philosophy just like how the MKS-80 is somewhere between the Jupiter 8 and Jupiter 6 design-wise.

The GR-700, GR-77B and MKS-7 also use those Juno voice chips.

These synths have X amount of voice chips that decide how high your polyphony will be. The internal software cycles through the voices each time you press a new key. So if one of them is broken, it will stop every time you get to that particular voice chip. Doesn't have to be specific notes. Some synths let you disable faulty voices too. I think you could do that on the Prophet-5? Effectively making it a prophet-4.

I think the Juno/Mks chips contain a full single voice. Filter, oscillator, vca.

My Andromeda A6 has its own menu where you can disable faulty voices too.

Bitexion wrote:These synths have X amount of voice chips that decide how high your polyphony will be. The internal software cycles through the voices each time you press a new key. So if one of them is broken, it will stop every time you get to that particular voice chip. Doesn't have to be specific notes. Some synths let you disable faulty voices too. I think you could do that on the Prophet-5? Effectively making it a prophet-4.

I think the Juno/Mks chips contain a full single voice. Filter, oscillator, vca.

My Andromeda A6 has its own menu where you can disable faulty voices too.

The 80017A is just the filter and VCA...

Unfortunately you can't disable bad voices on the Rolands...