Troublemaker

Here it is.
The reason I've just spent the last hour with screwdrivers, wire strippers and a soldering iron. Back in the nineties someone somewhere was producing button batteries with machine soldered circuit board connectors. Yamaha in their wisdom bought thousands and installed them into units like the QR10.
They make the circuit board look tidy and they probably earned a few quid for certified Yamaha repair shops. They take about half an hour of a technicians time to replace. In all honesty I imagine Yamaha didn't think anyone would be using the units past the internal battery's shelf life. They would have produced something better and more capable in that time.
If you started out in the nineties with a QR10, chances are that these days you're shelling out around £2000 for a Tyros 5.
I do love Yamaha for their dedication to producing hardware. They've never ventured into creating a software DAW and I'm glad they haven't.
These music composition machines from the early nineties onward have a bit of a cult following and people such as myself collect them, and mod them to extend their life. The QR10 I've just modded is perfect if you can't play keyboards, or bass or drums. Everything is there to get some kind of musical structure to your own tunes. It has features for creating tracks from scratch, something I'll get round to one day. In the meantime it's great for just getting a basic idea of the ground and running.
I'm glad I spent the time elongating this particular QR10's timeline.