Ensoniq EPS 16 Plus

It´s an good old sampler, quite useful. Sampler, effects, onboard sequencer. Read more about the sampler on Vintage Synth Explorer. Unfortunately they can sometimes break or behave very randomly. But hey, they are old nowadays so it´s normal.

The story:

I´ve got may hands on two units with different errors. One has some internal errors on the ADC-stage and the other one does not boot up at all. The problem is that Ensoniq, the good old company, never really released any schematics. Their way of handling defect units were to replace the internal boards. A quite expensive way of repairing.


After some thinking, I decided to pull apart the samplers and try to get one working out of two units. And it almost worked. I now have one semi-working unit which starts up fine, runs fine for 20-30 minutes and then freezes up. Opening up the unit once more and carefully cleaned ALL connectors removed some of the errors. And with ALL I also mean the connectors inside the clavier itself. I still got "System Error 131", "System Error 137" and sometimes "System Error 129" among others even after the cleaning. But after making a new O.S-disk some of these errors seems to have stopped. And it ran for a whole evening without freezing. Yeah!

I still have some issues with the effect parts. When selecting an effect, it can sometime render a confusing error spelled "EFFECT DOWNLOAD FAILED" and then shuts of the effect. After that I can select another effect like reverb or delay and it works fine. Strange behavoiur.

ensoniq eps 16 plus repair.jpg
Here are som nice picture of the event. Two fullsize samplers pulled apart means you have a full kitchen table of screws, parts and whatnot.

Nice resources:

O.S-disks for Ensoniq EPS/EPS 16 Plus/ASR and other..