Some of the key combinations differ from the keyboard version to the desktop version. (At least they do, on the sister device OB-6). For example, you stated hold + portamento + 3 for checking internal temps. That’s the same on the OB-6 desktop version. On the keyboard version, it is transpose + 3
I don’t think any of these are ‘secrets’ per se..
If you stumbled onto some hidden way of overwriting the permanent banks 5-9 . . . that is indeed miraculous, as it is likely non-volatile ROM memory. Maybe not? Have you powered off, and back on - your Prophet? Is the change still there??
Yes they are still there. I think that, as on all DSI synths, the presets are stored in flash ram, but only the software prevents them from being overwritten.
Trying to find that combination again (which I did), I've also discovered that on the Desktop version, holding down "Hold+Portamento+9" copies the presets banks 500-999 to the User banks 000-499.
Again on the desktop version, holding down "Hold+Portamento+0" copies the User banks 000-499 to Presets banks 500-599.
I really wish that those functions would be listed in the manual, or that someone from DSI would have told us about them.
Same thing with the "Debug Menu" on the Prophet REV2, it's actually DSI support that told a user who was having problems with his REV2 to access that hidden menu by a "secret" button combination. That menu offers the possibility of overwriting the presets as well.
NOTE: the combination to clear the temperature tables is not Manual+3 (as I erroneously wrote in my first post in this thread), but rather holding down "Hold+Portamento+4" on the desktop version.
DO THIS AT YOUR OWN RISKS, since this will clear all tuning reference data and you will have to rebuild those tables by holding down "Manual+0" many times in the following days and weeks at different times and room temperatures in order to build it back up again. You have been warned.