Vintage Synth Explorer Forums

Hello,
My friend's Prophet 600 control panel suddenly stops to work properly: all knobs don't respond to control any more.
Arpeggio stops to work too, also it doesn't trigger an external instrument through midi out.
All the presets sound the same: a sort of spacey sound...
Whatever key of the keyboard you press the sound doesn't change in pitch.

What could we do?
Had you got a similar experience?

Thanks

sounds like the internal memory battery has died, altho that shouldn't stop the MIDI out...except if the MIDI out off/on/chan# is memorized in RAM somewhere.... power supply failure?

You can turn off the presets on the P-600 by just pressing the Preset button on the membrane panel, when the Preset LED is off the knobs revert to a "what you see is what you get" configuration. Unfortunately, I don't know of a way to get it into this mode (which would be helpful for figuring out if it's just a preset problem) if your membrane panel is shot.

This guy: http://myworld.ebay.com/technologytransplant/ sells newly manufactured replacement membrane panels (I got one as a back up but thankfully haven't had to use it yet; think it was around $40USD). He doesn't have any listed at the moment but seems to offer them on a semi-regular basis.

The machine is in my friend's studio 25 kilometers away from here, so I tried it few times.
In 90s, Prophet belonged to an italian quite famous trance dj: we don't know how he took care of it.
It definitely stayed turn off for some years.
From february, my friend become to use it almost every day, and as I tried, it worked good:
All knobs worked, and keyboard responded correctly.
At first only memory presets didn't work in the right way, but day after day, taking it turned on, it found again presets.
THE PROBLEM is that NOW althought using"manual mode" turning any of the knobs or pressing any part of the keyboard, no changes happen. It sounds always in the same way.

memory membrane buttons work fine: when you press it the right number is on the display...

I had this problem..Esp when it was not used for a while.

I found that cleaning all the pots helped and turning the mod wheel a few times before use.

Changing the battery is always a good thing to do.

When i used it often the problem went away.