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"One of the most innovative items Yamaha produced. It's got the same sound chip as a TX81z, deliciously grainy effects, a sequencer, basic sound editing from the front panel --- oh, and a clock. By Clock, I mean days, months years, hours clock. It has a real time clock chip inside, and when the screen times out, you get a nice clock.
You can see pictures of this machine, and internals of this unit, and general information
here.
My unit has Click Out modification that I developed. The machine has a metronome you can turn on, but it's a very loud, very harsh digital beep which is added after the volume control. If you insert a jack into the socket on the right of the machine, it outputs this beep through that socket. You can then run it through a channel on your mixer, EQ down the harshness, use it to trigger tap-tempo equipment without MIDI to keep it in tight synch with this."