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Hey,
I was having a small problem with this Onkyo surround amplifier.
There was bad contact in the output protection relay and I was going to order a replacement.
However, I first decided to measure the coil voltage. It was about 12V as expected. However, on my scope it showed a ripple of about 5 volts.
I thought this seemed a bit much, so I had a look at the power supply. Most the big capacitors were fine, but a few of the smaller ones had high ESR (3-5ohms, when less than 1.5 would be expected), and I replaced some of them. Then I put the amplifier back together. So I switch the amp back on, relays click and display looks as usual. Everything seems fine, except I now have no sound at all. In the headphone output I have a buzz, but no sign of the signal i'm feeding the input.
I've checked the power transistors, and the input signal does not reach them. So I guess by repairing the PSU I have only made matters worse. Now I really need some help with this thing. It's packed with electronics, and it's difficult for me to understand even where to begin looking for a signal. This sort of reminds me of when I last tried repairing a surround amplifier, and it caught fire in the process
The service manual can be found by googling "onkyo a-sv810pro service manual"
I'm not allowed to post URLs on this forum until I've made 15 posts, or I would have linked straight to the file.
I was having a small problem with this Onkyo surround amplifier.
There was bad contact in the output protection relay and I was going to order a replacement.
However, I first decided to measure the coil voltage. It was about 12V as expected. However, on my scope it showed a ripple of about 5 volts.
I thought this seemed a bit much, so I had a look at the power supply. Most the big capacitors were fine, but a few of the smaller ones had high ESR (3-5ohms, when less than 1.5 would be expected), and I replaced some of them. Then I put the amplifier back together. So I switch the amp back on, relays click and display looks as usual. Everything seems fine, except I now have no sound at all. In the headphone output I have a buzz, but no sign of the signal i'm feeding the input.
I've checked the power transistors, and the input signal does not reach them. So I guess by repairing the PSU I have only made matters worse. Now I really need some help with this thing. It's packed with electronics, and it's difficult for me to understand even where to begin looking for a signal. This sort of reminds me of when I last tried repairing a surround amplifier, and it caught fire in the process
The service manual can be found by googling "onkyo a-sv810pro service manual"
I'm not allowed to post URLs on this forum until I've made 15 posts, or I would have linked straight to the file.