Here is a the procedure for a reset of the V50
V50 Factory Reset procedure
WARNING: All user stored data will be deleted. If the current settings and data are not expendable, create a backup before executing the Factory Reset. Internal Voice, Internal Performance, Setup, Sequencer Data (All Songs, and Setup), Rhythm Machine Data (Pattern, Song, and Setup) will be deleted.
1) Turn on the power.
TIP: All buttons must remain depressed and be pressed in the order mentioned in step #2 for proper execution.
2) Press and hold down the [SEQ] button, then the [CARD] button (located next to the Demo button), and then the [DEMO] button.
3) Continue to hold the buttons down until the dialog box appears in the display. The display will first indicate the V50 Test Program and Main Rom Version then will automatically display the question: 'Test Entry Manual?'
4) Press the [DEMO] button. The screen will display: 'Factory Set?'
5) Press the [+1/YES] button. 'OK' will appear beneath the 'Factory Set?' readout, indicating completion of the Factory Reset, and the V50 will automatically return to Play Mode.
I have some V50 patch files in sysex format at http://synthzone.com/midi/yamaha/v50/
and you will need a MIDI utility like MidiOx http://midiox.com/
to transmit these to your V50.