yamaha amplifier AX-700

jeeva

Member
2010-09-18 12:48 pm
Hi I have just joined the forum and new to this . I am trying to repair my Yamaha AX 700 . I have the left channel working . I have ran comparisons against the right ch. which keeps blowing the outputs , driver and predriver transistors. I have noticed that the dc . voltages on the emitters and base of the working channel as well as the blown channel pulses.The collectors are stable at -64 and +64 . any one has any suggestions
Regards,Jeeva
South Africa
 

jeeva

Member
2010-09-18 12:48 pm
yamaha Ax 700

Hi shaun ,thanks for the reply and my thanks to Ebbe for the schemastics.
I have purchased the output transistors from a supplier here in Durban ,South Africa. Yes I have heard from Jim in Madrid about the suspicious components been supplied worldwide. I have been directed to a company in Johannesburg to repurchase my components needed, Your suggestion about the spares used been faulty is believable ,since all measurements against the working channel seem okay. I will be getting the new spares on Monday . I will keep you posted
Best regards,
Jeeva