Hi all,
I am working on an Aragon 8008BB. One channel blows the negative fuse on power up a few times. I have verified there is no short in the power and speaker wiring and then taken out the assembly (PITA!!) and desoldered every power transistor and bias transistor and tested them. All junctions tested fine and I tested the driver transistors on the board for diode drops and they look fine too. Did that to the pre-drivers as well. Bias pot tested in range.
Not able to find any smoking gun, I want to get everyone's thought as to what else I should look at before I put it back together and most likely go back to blowing fuses.
Thanks in advance!
PS. Measured power supply voltage at +/-74V with the fuses not installed. The other channel works fine.
I am working on an Aragon 8008BB. One channel blows the negative fuse on power up a few times. I have verified there is no short in the power and speaker wiring and then taken out the assembly (PITA!!) and desoldered every power transistor and bias transistor and tested them. All junctions tested fine and I tested the driver transistors on the board for diode drops and they look fine too. Did that to the pre-drivers as well. Bias pot tested in range.
Not able to find any smoking gun, I want to get everyone's thought as to what else I should look at before I put it back together and most likely go back to blowing fuses.
Thanks in advance!
PS. Measured power supply voltage at +/-74V with the fuses not installed. The other channel works fine.
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you put back each pair driver transistor with one pair power output transistor and use 10 ohm 1W resistors to replace the fuses to test it.
If something wrong the resistor will burnt and limit the current.
If something wrong the resistor will burnt and limit the current.
Hi,
Another suggestion it is to check the resistances at the fuse to see if you have a low resistance.
Another suggestion it is to check the resistances at the fuse to see if you have a low resistance.
Hello all,
Thanks for all your quick suggestions!
I did find the issue. The previous owner was doing something in the power supply section and disconnected a bunch of wires there. Even though he labeled all of them, he mixed up the two wires from each speaker output to the protection board inputs. I reversed them and now the amp is happily idling.
Thanks again for you guys' help!
Thanks for all your quick suggestions!
I did find the issue. The previous owner was doing something in the power supply section and disconnected a bunch of wires there. Even though he labeled all of them, he mixed up the two wires from each speaker output to the protection board inputs. I reversed them and now the amp is happily idling.
Thanks again for you guys' help!