Hi here,
I'm new to this group, hence the late answer.
I actually had a similar issue with a DX7: sometimes it booted up Ok, but most of the time, it hanged with cryptic glyphs on the LCD.
To cut long (debug) story short, I monitored the timing between poweron and the /RESET signal (pin 6 on 63B03 = IC60) with an oscilloscope. Datasheet says on boot, it should stay low for 100 ms, but?in my case, it went high after 40 ms.
The cause was the 10/16 tantalum close to the battery (in K2 on the schematic); I replaced it, and everything went OK.
HTH,
cheers
Fran?ois
alesisfusion8hd