Anyone know a source for schematics for this item?

I was hoping there might be a Service Manual, but there isn't. Try Casio direct.

https://www.google.com/search?q=casio+ctk+900+service+manual

Lots of Owner's Manuals
..

Service Manual for sale on eBay

ttps://www.ebay.com/itm/Yamaha-Electone-Keyboard-HC-2-HC-4-Service-Manual-Schematics-Parts-List-OEM/302676480589?hash=item4678ec924d:g:iToAAOxynwlTcjai

Yamaha Electone Keyboard HC 2 HC 4 Service Manual Schematics Parts List...

The best source of wiring schematics is the Seymour Duncan site. Here's the link-

Wiring Diagrams

For what piece of gear?!?!?!?!?!?!?

You didn't mention what item you need a schematic for? At any rate, contact the manufacturer directly for the info.

http://intl.fender.com/en-CA/support/ Schematics are here. PDF I believe. You might mean this:http://intl.fender.com/en-CA/amplifier-parts/amplifier-controls-and-electronics/?sort=name&series=capacitors_diodes You can always ask them.

No hope. I have replied to this sort of question elsewhere but Behringer are very protective of their stuff and won't even let us have diagrams. Only Behringer service. If anyone has any Behringer service manuals / schematics we would love them

What is the model of this unit so I can find a schematic?

You would need TWO DC supplies as they use AC so they can create both a plus and minus 15 volt power source to run the internal op amps.

Here is a schematic for the 1202 which has same power supply configuration as the 802.

http://elektrotanya.com/behringer_xenyx_1202.pdf/download.html

Scroll down to the little link "Get Manual" and download the service manual and schematic. You will find the power input in the upper left corner of page 5.

Here is the link to the closest information you will find:http://www.pat2pdf.org/patents/pat4050343.pdf It is the schematic. You might try asking for the source for an owners manual at this site:http://makerspace.org.nz/content/moog-satellite-adding-cv-and-gate-out-jacks Apparently they were manufactured by the Thomas organ company. Try this link:http://www.organservice.com/ Let me know if this helped.