Prophet 6 strange behavior

[Silesius]

Hello, I bought a second hand Prophet 6 (os 1.7.5). As you can see in the attached video it acts strangely when I press some buttons. At first I thought it could be some kind of usb midi feedback from my daw, but it seems something else. In the video the Prophet is only connected to a normal midi keyboard (no sequencer, etc). You can play it, change presets, move the knobs and everything works as expected. But, for example, when I press the "Lfo Amount" button in the aftertouch section it makes the sequencer start... other unexpected things happen when pressing buttons in sections like the filters, vco 2, lfo, etc: the synth enters Global mode, the presets change, some leds turn on or off, the fx parameters change, the sequencer starts and stops, a button press turns on or off another buttons, and other crazy things. For the moment I performed a reset, but nothing has changed.
I've been searching but I'm not finding any information about this kind of issues. Any ideas about what's happening?

https://youtu.be/kKiJsk8uJL4

[timboréale]

Does it do all that with the MIDI cable unplugged too? If so, contact support...

[Silesius]

Does it do all that with the MIDI cable unplugged too? If so, contact support...

Yes it does, I've just tried. I will contact support, but I thought perhaps somebody here has had a similar problem and knows how to fix it.

[timboréale]

It's possible an internal cable just needs to be re-seated between the main board and the panel, but there's always the risk it might be a deeper electrical issue too. Support will know best how to troubleshoot it. If you're handy with electronics, though, opening it up, and re-seating all the ribbon cables (on both ends, if both ends have clips) between the panel board and the main board wouldn't hurt. If you're not familiar with that stuff though I'd suggest waiting to hear what support recommends.

[Silesius]

Thanks for your help Timboreale, I will contact support before trying anything. I’ve been building diy synths for almost twenty years, so I think I will be able to try any procedure they tell me to do, if necessary.

[Silesius]

I'm happy to say my Prophet 6 is working now!  I contacted support and they told me the same thing timboréale said, open it and try to re-seat the ribbon cable between boards. It worked. Thanks again timboréale, you were right!

[timboréale]

I'm happy to say my Prophet 6 is working now!  I contacted support and they told me the same thing timboréale said, open it and try to re-seat the ribbon cable between boards. It worked. Thanks again timboréale, you were right!

Wonderful, I'm glad you're up and running normally!