Most LC103 issues stem from a few known physical components rather than complex logic failures.
Some technicians successfully use DeoxIT spray, though opening the relay to clean contacts with a sliver of a business card soaked in alcohol is more effective. Repair Of Sencore Lc103 Service Manual
Finding a true "Service Manual" (with full theory of operation) is notoriously difficult for the LC103, but the following resources are your best substitutes: Most LC103 issues stem from a few known