The DH100 is featured in Reed Ghazala's book on circuitbending. Mine is still unbent. I like the expressiveness. Blowing this thing with it's cheesy sounds feels more real than any sample can do for me.
Casio DH100 service manual (including schematics) DH100service manual.rar Olivar Premier sent me this. Thanks.
Unrarred Casio HD100 service manual JPG's on this page.
aug 2006 update: Kerry's been at it again! Here's his HD-100 Resonance pot page.
If you have a DH100 emitting a whining sound even when not playing: You can fix this.
Go to DORIAN'S DH100 PAGE http://www.btinternet.com/~dorian.rose/
Other repairs and Breath control adjustment at Paul Fox's Casio Horn Page: