Hi
I have been working on an Onkyo A7. I have upgraded a number of these before and sorted out all sorts of problems, however this has me stumped. I have replaced all the electro caps and have the amp working- except if I attach a load (speaker or dummy load) to the output and then it draws massive current. At idle with no load it is about 0.2 amp which seems about right.
I have tested the output transistors and they seem fine (peak transistor tester), and as I am doing an upgrade on this unit I changed out all the main board transistors (all of which tested ok). There is negligible DC on speaker terminals. All the voltages on the main board measure fine
When I put tone in and test at the relay there is signal on both sides (input and output), and the relay works and the associated circuitry measures appropriately.
So I have been looking for cables issues, or anything else, but am I missing something basic?
schematic attached and all help appreciated
Peter
I have been working on an Onkyo A7. I have upgraded a number of these before and sorted out all sorts of problems, however this has me stumped. I have replaced all the electro caps and have the amp working- except if I attach a load (speaker or dummy load) to the output and then it draws massive current. At idle with no load it is about 0.2 amp which seems about right.
I have tested the output transistors and they seem fine (peak transistor tester), and as I am doing an upgrade on this unit I changed out all the main board transistors (all of which tested ok). There is negligible DC on speaker terminals. All the voltages on the main board measure fine
When I put tone in and test at the relay there is signal on both sides (input and output), and the relay works and the associated circuitry measures appropriately.
So I have been looking for cables issues, or anything else, but am I missing something basic?
schematic attached and all help appreciated
Peter