No sound output tube amp, it should first check the power, watch the filament is lit, the case temperature is normal. If the filament is not lit, the tube shell cool, you should check the amplifier tube filament and the anode voltage is normal or not. If the voltage is not normal, and then into - further checking the power circuit, the load circuit when necessary, disconnect the power to determine the load power circuit fault or short circuit. If the voltage is normal, in the center of the first volume potentiometer joined DC intermittent interference signals, if a strong reaction, indicating that the normal post-stage amplifier circuit, fault preceding stage McIntosh tube amp repair methods without sound amplification circuit; contrary , failure in the post-stage amplifier circuit. Respectively, and in the promotion of the gate of the gate of the input amplifier tubes joined interference signal, where - plus interference signal level no response, indicating that the level back of the circuit is not working properly. Suspicious components (eg valves) available substitution method overhaul. Mention technical support and accessories manufacturers, quality assurance. Amplifier repair technicians engaged in more than 20 years, experienced, first-class technology. There are bad repair power amplifier, power amplifier disorder doctor died, can not find the parts, and human factors, and so we can repair; data disorder, CPU damage, can be reprogrammed. McIntosh MC402 after the class, MC601 after the class HIFI amplifier, MC2102 after gall MA7000/6900/MCD301, MC1000 other models professional repair. McIntosh McIntosh Audio Contributing Technical Center Address: Tianhe District, Guangzhou Huangpu Road West, No. 6. Welcome home delivery machine or mail! Entrance to parking! National direct dial telephone 4007773202 E-mail: 2984014540@qq.com Q number: 2984014540.