I picked up a 600a4 the guy i got it from told me it gettint really hot and shutting off so i did a bench test and it drawing 9amp's at idol so i take a look inside the amp and to my surprise someone turned all four gains all the way up so i turned them down new it's only drawing 1/2amp. Here my question how do i set them back right without a oscilloscope ?
The potentiometers that are not accessible with the cover in place are the bias potentiometers. If you have an amp meter on your 12v power supply, turn them clockwise until you just BARELY see an increase in current draw. Do this for all 4 channels. The current draw should be well below 2 amps after they're all set.
You MUST have all semiconductors clamped tightly to the heatsink when doing this.
You MUST have all semiconductors clamped tightly to the heatsink when doing this.
OK i think i got it now it idling at 1.57amp's and i let it set for a hour at idol and it stayed the same and the bias on all four is set at 3.61mv any higher and it starts draw a lot of current then i let the amp run for a hour at 3.4 volume it got nice and warm but did not shut down the one thing i did notice the rear right & left is running hotter then the front right & left is that some thing i need to worry about? and the two transistor's in the center of the 600@4 U3 & U4 get quite warm at idol is that normal? And all four channels nice and clear.
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The regulators and the output transistor's are cool to the touch even when the heatsink is hot and the idle current go's to 1.73amp's after i get the amp really hot but drop's back to 1.57amp's pretty quick after input signal is off the only two that get hot at idle is in the picture below i am not sure what they are regulators or transistor's i can't read the numbers because of the heatsink
An externally hosted image should be here but it was not working when we last tested it.
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