Skip to content


Roland MKS-70 repair at Plasma Music

Recently, this gorgeous vintage analogue Roland MKS-70 synth module came in for repair.

The MKS-70 is basically the rack version of the Roland JX-10 keyboard synthesiser, which itself is essentially two JX-8Ps. Often refereed to as the Super JX, the JX-10 and the MKS-70 ooze analogue tone and both deliver pristine sound quality.

Check out more details and some sounds here.

Anyway, the customer said that it wasn't powering up properly with just a flash briefly appearing on the display and then nothing. Well, let's see if we can get this ol' girl singing again..

Apart from being a giant classic analogue synth, the MKS-70 like the MKS-80, has hinged circuit boards which means that it opens up quite nicely. Having said that, if you need to get at the 'CPU' board (the service notes refer to this as the Assigner board, for some reason), you really do need to disconnect and remove the lower analogue voice board.

Switched-mode power supply for Roland MKS-70
Switched-mode power supply for Roland MKS-70

Before I did that, I checked the voltages on the power supply which were all about 25% more than they should be. Eek! Hope no serious damage has been done.

I'll keep you posted on this fix but please bear in mind that I'm respecting the COVID-19 lock-down so it may be a while before I'm back.

In the meantime, please check out MKS-70 power supply and OLED display replacements here.

If you've got one of these, I'd love to know! If it needs a little TLC, then just contact me.