Hi, working on a Hifonics ZRX3000.1D Zeus. Had positive rail on the speaker output. I pulled the IRF9640s and it went away of course. Nothing was shorted. I have no drive. I have audio input on the in side of R131 (see pic). But I don't have it on the out side going to the input of the driver board. The driver board is new from Amp Lab. Any help would be greatly appreciated. Thanks.
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No. I lose it at the input to the board. I have signal on R131 but not on the side going to the driver board. The driver board is new from Amp Lab.
Is the resistor within tolerance?
What's the resistance between the driver board input (connected to the resistor) and the audio ground terminal of the driver board?
What's the resistance between the driver board input (connected to the resistor) and the audio ground terminal of the driver board?
Check the output of the -5v regulator behind the driver board. It's in a TO-92 package.
The diagram below has the pin configuration for the driver board. It's easy to check voltage there.
For pins that are difficult to reach, make a probe like the one below.
The diagram below has the pin configuration for the driver board. It's easy to check voltage there.
For pins that are difficult to reach, make a probe like the one below.
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Okay, found the problem with the amp. It was my own ignorance. I didn't understand Perry when he asked if I had the +5volts. I my mind I just saw +5 volts. Sorry. The inductor feeding the -15 volts to the -5 volt regulator opened up. Replaced the inductor and all is well. Thanks Perry Babin and Billy Armstrong for the help. I will know to look for both next time.
In most repairs, the first thing you do is to confirm that all power supply voltages and grounds are as they should be. Sometimes, I still forget this. It's easy to get sidetracked.