Repair of Creative Labs DTT2500
Hi
I am currently attempting to repair my Creative Labs Desktop Theatre amplifier, I am getting no output from the Subwoofer channel, if you run the speaker test this again provides white noise in turn on each channel but no output on the subwoofer. (Yes I have confirmed that the speaker is working ok) Unlike the other 5 channels the subwoofer does have a line out, if I connect an amplifier and speaker to the subwoofer line output and run the speaker test I do get output on all 6 channels therefore I believe the decoder card is working correctly. I have dismantled the unit and checked all connections they visually appear to be ok, also the unit is on two PCB's a decoder pcb and the 6 channel amplifier pcb, the subwoofer line out is also on the amplifier pcb therefore the signal must be getting that far. If I touch the input pin of the subwoofer power amp IC I get the expected mains buzz, therefore I am fairly happy that the power amp chip is working. Therefore it must be in the preamp stage someware. I did try to obtain the circuit diagram from Creative but they said, "Unfortunately I cannot give you a circuit diagram of the amplifier. We don't supply this kind of information" which was polite but not very useful. Before I sit down at attempt to trace the circuit out I was wondering if anyone had already done this. Also each channel has an 8 pin IC marked 072D and JRC, I dont recognise JRC but I am wondering if it is a dual opamp like a TL072, from what I have traced of the circuit so far it does look possible. Has anyone had any experience repairing one of these, or recognise the chip. Thanks Dave |
Repair of Creative Labs DTT2500
Just in case anyone was interested, I found a dry joint and it is now
working fine. Dave "Dave Widgery" wrote in message ... Hi I am currently attempting to repair my Creative Labs Desktop Theatre amplifier, I am getting no output from the Subwoofer channel, if you run the speaker test this again provides white noise in turn on each channel but no output on the subwoofer. (Yes I have confirmed that the speaker is working ok) Unlike the other 5 channels the subwoofer does have a line out, if I connect an amplifier and speaker to the subwoofer line output and run the speaker test I do get output on all 6 channels therefore I believe the decoder card is working correctly. I have dismantled the unit and checked all connections they visually appear to be ok, also the unit is on two PCB's a decoder pcb and the 6 channel amplifier pcb, the subwoofer line out is also on the amplifier pcb therefore the signal must be getting that far. If I touch the input pin of the subwoofer power amp IC I get the expected mains buzz, therefore I am fairly happy that the power amp chip is working. Therefore it must be in the preamp stage someware. I did try to obtain the circuit diagram from Creative but they said, "Unfortunately I cannot give you a circuit diagram of the amplifier. We don't supply this kind of information" which was polite but not very useful. Before I sit down at attempt to trace the circuit out I was wondering if anyone had already done this. Also each channel has an 8 pin IC marked 072D and JRC, I dont recognise JRC but I am wondering if it is a dual opamp like a TL072, from what I have traced of the circuit so far it does look possible. Has anyone had any experience repairing one of these, or recognise the chip. Thanks Dave |
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