You'll find Manitowoc service manuals at www.manitowocice.com/Service/Service.asp, Ice-O-Matic manuals at www.iceomatic.com/general.asp?article=technicalsupport.xml&epds=no, Scotsman manuals at www.scotsman-ice.com/general.asp?article=manualdownloads.xml, and Hoshizaki service information at www.hoshizakiamerica.com/tech.asp.
The service manual provides crucial information about the ice machine refrigeration system and electrical controls, so there's no reason to hesitate about breaking it open during service calls.