Technics SU - X901 Amplifier Repair

Fault Loss of Audio after a few minutes of operation. This particular Amplifier had seen extensive usage. The video shows the state of the cooling fan and circuit boards that were covered in a thick layer of dust and dirt. Amplifier taken apart and thoroughly cleaned. Next all the dry solder joints on the input RCA sockets and connectors reflowed. Speaker Terminals and series regulator power transistors re-soldered. The speaker protection relay was replaced 24 V DC Coil DP/CO. Tone board user controls cleaned with De-Oxit to ensure noise free operation. The head phones socket was also re-soldered. The display and back filter were also cleaned, again covered in dust. The volume encoder as shown was virtually seized and very difficult to turn. Encoder taken apart and cleaned with de-greasing and release fluid. Contacts cleaned with a fibre glass pencil. The Amplifier was re-assembled and tested, but the Audio output would fail after a few minutes and the Audio Output IC ran hot. Replacement genuine original SVI 3205 power Amplifier module fitted fixing the issue. Amplifier fully tested working correctly.