Cambridge A3i Amplifier Repair скачать в хорошем качестве

Cambridge A3i Amplifier Repair

Fault Amplifier powered up, but the speaker protection relay would not switch over, hence no Audio. The standard repair procedure for the A3i is to replace in the first instance the 4 Green LEDs on the Amplifier PCB. The LEDS break down over time and go intermittent open circuit. This particular Amplifier also required Q8 BC640 and Q7 ZVP3306 FET replacing. Q7 had failed and measured diode junction on the Transistor tester. Q107 and Q108 for the other channel were also replaced due to the ZVP FET also reading Diode junction. Note: The FETs and the transistors run hot under normal operation. The soldered connections on the Amplifier PCB were also re-soldered as there were many dry soldered connections. The speaker protection relay also had to be replaced, to avoid intermittent loss of sound at low volume, due to oxidization on the switching contracts. 24 V DC DP/CO The Amplifier was tested and the speaker protection relay changed over. The bias for each channel was set to 12 millivolts when measured across R123 & R23, the user controls were also cleaned with De-Oxit to ensure noise free operation. Amplifier fully tested correct operation