STK411-210E is a thick-film hybrid integrated circuit (IC) manufactured by
Always implement a (usually involving a relay) between the IC output and the speakers. If the STK411-210E fails, it often shorts Vcccap V sub c c end-sub Stk411-210e Datasheet
The STK411-210E has a 21-pin SIP package, with the following pin configuration: STK411-210E is a thick-film hybrid integrated circuit (IC)
Typically remains below 0.1% to preserve audio signal integrity. Pinout and Internal Architecture Stk411-210e Datasheet
This is the most common cause of failure. Ensure the thermal paste between the IC and the heatsink is fresh and that the heatsink is free of dust.