Here are some helpful files in PDF format. Some of these files are written for trained service tech's, so if you don't completely understand the content, best to hire someone who does.
Electrical and Error Codes
Balboa M7 Service Manual VS Systems Lots of Manufacturers use Balboa System Controls
Balboa Service Manual. Works for Platinum, Select, Echo and Z Series Models built before 2001.
Plumbing and Jet Repair