I am new owner by accident. I have collected Fusion 8hd from junk. I paid something like 15 euros for it. Assuming that is dead and hoped that is not empty inside. Turning on was dead synth as I suspected. I had only backlight and sporadic button leds lit. Since I work professionally with digital and analog electronics, also did lot of designs of digital systems I gave chance to repair the HD8. After spending some time figuring out www (What Went Wrong) and without any schematics, it took me 10 hours to understand little bit more by downloading a lot of integrated circuits datasheets. Finally after major brainstorming I have discovered one small component (single input Schmitt trigger) which is in charge of conditioning of clock signal form one of resonators to one of its CPU's. The part cost me 2 euros + 25 for shipping. Now this Alesis is brought back from total death.. So at first glance I love this synth! And now I am here, total newbie with this synth.
Congratulations with your diagnostics and repair of your Fusion 8HD, pleas post the information on this diagnosis and repair and possibly a PDF file documenting this.
Pictures of the PCB and component can be helpful to other Fusion owners.
This may be of help to me in repairing one of my 8HD's that has no working video display, I know the top half is fully functional because I have connected it to the bottom half of my working 8HD and then it works properly.
Take Care ... Jesse
Jesse My Gear: Tempus & Yamaha drum kits, Remo Djembe, Matador Bongo's, Ibanez SD GR 5 string Bass guitar & 100 watt bass Amp, (2)Alesis Fusion 8HD keyboards, (2)SUMO 300 amps, Multimix 16 Firewire mixer, AKG D112 mic, 2 Behringer B2 Pro Stuio, Shure Beta 58a & 2 AKG D8000M mics, PC with Audigy sound card and Adobe Audition 3.0