tried to reactivate my trusty old xp-50 today after quite a considerable time today. I started up, then got the message "user memory damaged/ battery low". So I changed the battery; afterwards, on starting up, those black blocks that appear on startup would briefly blink, the current sound would appear for a short time, barely readable though, and then the whole display would just go bright orange (sounds are still there, though). At first I thought "oy, I damaged everything", but after changing back to the old "low" battery, the display works just fine.
I have experiences problems with several synths when using the wrong battery. On paper the battery type should make little difference as long as the voltage is OK, however it seems to be down to width and diameter, the contacts have poor connections.
Better than the old days when you had to solder them on!
If the battery is the right one try doing a sys ex dump out of and into the synth, often a synth can be revived by doing this.
the battery is the right one (cr 2032), at least on paper; it seems to fit properly, too.I have no equipment for testing of exact voltage. the synth itself seems to be alright too; the sounds and knobs seem to be still working, as far as I can tell, which is not very far, as the display wont work..
apparently changing the battery just changed the contrast settings in some way just pushing "system", "2" and turning the knob to the right brought the display back to life.