Is the 7915 operating at a significantly higher temperature than the 7815?
Did you insert a 1 ohm resistor between the output leg of the 7915 and the board and measure the voltage across that resistor to determine if the current being drawn was more than the regulator is rated for? This is covered under item #26 of the audio troubleshooting page of the DVD.
Did you insert a 1 ohm resistor between the output leg of the 7915 and the board and measure the voltage across that resistor to determine if the current being drawn was more than the regulator is rated for? This is covered under item #26 of the audio troubleshooting page of the DVD.
Does the resistor burn with the A1381 out of the circuit? no.
Does it burn with the 1381 in the circuit but the A1023 connected to it out of the circuit? yes
That would likely indicate that you have a solder bridge somewhere. The current has to pass through a higher value resistor and the 1381 with the 1023 out of the circuit. That would cause the higher value resistor to burn (assuming that it's the same size) if the transistor was defective.
Look at the BP1200.1 schematic diagram in the JBL folder. The circuit is almost identical to this one. As you can see, there is very little that can draw current through the 1381 with the a1023 out of the circuit. The schematic has an error. It shows a direct connection between the base and emitter of the 1381 and also shows them going to ground.
I'm assuming that the 120 resistor that you're referring to corresponds to R233 and R333 on the JBL diagram.
I'm assuming that the 120 resistor that you're referring to corresponds to R233 and R333 on the JBL diagram.
I'm assuming that there were no driver boards in the amp.
IS the transformer shorted ?
i just checked. yes it is shorted primary to secondary.
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