Enhancement of the D4 basically. I've found the triggers are not as sensetive somehow. The D4 can be used well with my old simmons pads. Not so hot with the DM5. Can't get the response sensetivity somehow on those triggers. Haven't tried the DMpro upgrade.
Always verify power supply voltages if problem looks like it could remotely be power supply related. I have seen some bad solder problems and one intermittent processor reset problem that required a new board in an Alesis product. FOR RESET Hold "Voice" and "Output" while powering on. Backup data first of course.
Advanced Musical Electronics has a lot of parts for Alesis stuff. THey only deal with techs though.
I've also seen All electronics carry displays occasionally at low prices.Always feel free to ask or check my Parts
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