Cambridge 640A Azur Version 1 Amplifier Repair (With Audio Tutorial)
Fault Amplifier not powering on stuck in standby. Initial inspection confirmed FU1 & FU2 F6.3 Amp secondary protection fuses had blown indicating excess current draw. Output transistors checked and U3 SAP15N was short circuit. (Left Channel) Output transistors removed and the Amplifier powered up without issue. Replacement Sanken SAP15s installed and Bias adjusted to 13 millivolts. Due to brown glue contamination R43 150 Ohm 1/4-watt resistor was replaced. Speaker protection and power input relays replaced due to the age of the unit. User controls and Switches cleaned with De- Oxit to ensure noise free operation. Amplifier fully tested working correctly.
Fault Amplifier not powering on stuck in standby. Initial inspection confirmed FU1 & FU2 F6.3 Amp secondary protection fuses had blown indicating excess current draw. Output transistors checked and U3 SAP15N was short circuit. (Left Channel) Output transistors removed and the Amplifier powered up without issue. Replacement Sanken SAP15s installed and Bias adjusted to 13 millivolts. Due to brown glue contamination R43 150 Ohm 1/4-watt resistor was replaced. Speaker protection and power input relays replaced due to the age of the unit. User controls and Switches cleaned with De- Oxit to ensure noise free operation. Amplifier fully tested working correctly.