S-E-A

Proving that you make something idiot proof, along comes a better class of idiot..

I'm sure Roland would confirm this, but I thought they are using universal type power supplies in their products now.

Yes.. Don't "upgrade" your operating system until you know all your connected devices will work with it. Same is true for Windows users. Golden rule is: If it ain't broke, don't fix it.

bugger.. I've recently bought one second hand via ebay. It had a damaged volume control, this I've replaced, and the Juno is now perfectly serviceable. Wondering if yours has a similar problem, especially as it also seem...

What type of cables are you using, standard tip/screen type jacks, or tip/ring/screen (stereo) type jacks?

unbalanced..

It's a command problem with the D-50 sadly...

Hopefully you backed up the internal data of the JV30 before changing the battery.. You may need to do a factory redet of the JV30 to clear the low battery warning; (From Roland's factory reset list) JV-30 : Press CHORUS...

Is the MIDI receive LED on the 880 flashing when data is sent? Is the unit number of the 880 set to 17?

Pretty sure the Fantom uses a Switch Mode PSU's, so is auto sensing voltage wise..