Amp6b, fault in output 1
Hello Diy'ers
I've been trying to make a post on the 41hz forum, but after using 3 different email addresses, I don't get an activation mail. So I'll post my problem here instead:
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I've been working the whole weekend to assemble and troubleshoot my first amp 6b. I've been very careful in the assembly, and thought I had some pretty darn good shiny concave solders.
At first the amp would only play on channel 2. I then went through all the solders again, and cleaned the board, only to measure 12v on the cathode of d6 -, and the amp not playing at all. (perhaps the protection of the chip kicks in when rail voltage is coming through a faulty D10?) I've been through various troubleshooting threads, but nothing seems to help. Here's some data that may help in finding the problem:
5.1v over C2
0v over R7
8.2v over c5
2.2v to ground after input caps
12v to gnd on - side of L1, 0.1v on + side
5.9v to gnd on - side of L2, 5.9v on + side
5.8v to gnd on output 2 +, 5.9v for -
0.2v to gnd on output 1 +, 0.1v for -
Measure on cathode to gnd:
5.9v on D8
5.9v on D7
12v on D6
0.2v on D5
I've used this method by Scatchy to check the input paths, and the input resistors seemed ok. over the inductors it read 2 ohm on L2 + & -, and 2 ohm on L1 + and unable to measure on -.
I believe the problem is a fried chip, due to the voltage difference (possibly a short-circuit around pin 26), and possibly a bad solder on L1. The measured rail voltage on output 1 suggest a fried diode, how could this be?
Hope you guys can help me out, anything would be much appreciated!
Here are some pics of the board:
Hello Diy'ers
I've been trying to make a post on the 41hz forum, but after using 3 different email addresses, I don't get an activation mail. So I'll post my problem here instead:
__________
I've been working the whole weekend to assemble and troubleshoot my first amp 6b. I've been very careful in the assembly, and thought I had some pretty darn good shiny concave solders.
At first the amp would only play on channel 2. I then went through all the solders again, and cleaned the board, only to measure 12v on the cathode of d6 -, and the amp not playing at all. (perhaps the protection of the chip kicks in when rail voltage is coming through a faulty D10?) I've been through various troubleshooting threads, but nothing seems to help. Here's some data that may help in finding the problem:
5.1v over C2
0v over R7
8.2v over c5
2.2v to ground after input caps
12v to gnd on - side of L1, 0.1v on + side
5.9v to gnd on - side of L2, 5.9v on + side
5.8v to gnd on output 2 +, 5.9v for -
0.2v to gnd on output 1 +, 0.1v for -
Measure on cathode to gnd:
5.9v on D8
5.9v on D7
12v on D6
0.2v on D5
I've used this method by Scatchy to check the input paths, and the input resistors seemed ok. over the inductors it read 2 ohm on L2 + & -, and 2 ohm on L1 + and unable to measure on -.
I believe the problem is a fried chip, due to the voltage difference (possibly a short-circuit around pin 26), and possibly a bad solder on L1. The measured rail voltage on output 1 suggest a fried diode, how could this be?
Hope you guys can help me out, anything would be much appreciated!
Here are some pics of the board:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
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