Hi AK
I hope some of you might have some pointers for a recent Kenny purchase.
I bought a KA-7300 with a defective phono stage (as advertised). The amp otherwise works as expected but produced no sound at all through the phono inputs. The Tuner/Aux inputs that also pass through the board with the phono preamp work fine.
I opened the amp and (after some work extracting the preamp board) I realised that the power lines to the pre-amp board had been cut. I reconnected these and initially the phono inputs worked as expected. Then suddenly they stopped and instead of the sound signal there was just crackle and pop.
The preamp uses FETs and I understand they are difficult to source. The only silicon on the preamp board are the FETs (2SK68A (M) and (L)) and a few 2SA763WLs.
I suspect that the power lines to the preamp board were cut because of the problem. The way it worked and stopped makes me think I may have a transistor problem. The thing that is curious is that it affected both channels simultaneously with total loss of signal. Does this point to a possible cause?
There are 9 electrolytics in the board. At this stage I could swap them for cheap local substitutes to see if it is a cap problem. I'd appreciate any other suggestions about how to identify the problem.
Thanks, Jon
I hope some of you might have some pointers for a recent Kenny purchase.
I bought a KA-7300 with a defective phono stage (as advertised). The amp otherwise works as expected but produced no sound at all through the phono inputs. The Tuner/Aux inputs that also pass through the board with the phono preamp work fine.
I opened the amp and (after some work extracting the preamp board) I realised that the power lines to the pre-amp board had been cut. I reconnected these and initially the phono inputs worked as expected. Then suddenly they stopped and instead of the sound signal there was just crackle and pop.
The preamp uses FETs and I understand they are difficult to source. The only silicon on the preamp board are the FETs (2SK68A (M) and (L)) and a few 2SA763WLs.
I suspect that the power lines to the preamp board were cut because of the problem. The way it worked and stopped makes me think I may have a transistor problem. The thing that is curious is that it affected both channels simultaneously with total loss of signal. Does this point to a possible cause?
There are 9 electrolytics in the board. At this stage I could swap them for cheap local substitutes to see if it is a cap problem. I'd appreciate any other suggestions about how to identify the problem.
Thanks, Jon