TEAC A - R600 Amplifier Repair

Distortion on both output channels at low volume. This Amplifier had seen a lot of usage and the above issue develops with all Amplifiers that use relay speaker protection systems. The Video shows the main Amplifier board and the control / tone board removed from the main chassis. The four speaker protection relays were removed from the board and the switching contacts cleaned with a Diamond Spatula and De-Oxit. fixing the distortion issue. The contacts were badly coated in oxidisation and resistive. The power start up relay located on the circuit board at the rear left when looking from the front of the Amplifier was also removed and the contacts cleaned. Due to the age of the Amplifier the following work was undertaken to ensure trouble free operation. Input RCA sockets re-soldered many showed signs of cracked joints. Power regulators re-soldered, the solder showed signs of heat related stress fractures. Mic and Headphones socket re-soldered. dry joint on all head phones sockets is not uncommon due to mechanical stress. Front control / tone board removed from the facia. The video shows one of the user control potentiometer (Balance) taken apart, the contacts were very heavy oxidised. Cleaned with a fibre glass pencil and the carbon track cleaned with De-Oxit. The Treble / Bass and section switches also removed and cleaned. The volume encoder often associated with random channel changing or poor response was removed and thoroughly cleaned with a fibre glass...