This amps have one shoulder that's getting hot, and the output have a high friquiency noise( no audio), I check most of the components of the driver board
And they looks ok, all audio MOSFETs are measuring ok. U2, u3 have no part number and I can not check them. can some one tell me where the audio MOSFETs gate reference ground is? And by the way when this amp came to me Q220 and Q213 were shortened.
Additional help will be appreciated
Thank you
And they looks ok, all audio MOSFETs are measuring ok. U2, u3 have no part number and I can not check them. can some one tell me where the audio MOSFETs gate reference ground is? And by the way when this amp came to me Q220 and Q213 were shortened.
Additional help will be appreciated
Thank you
U2 - TL072
U3 - LM211
The gates are driven from the positive rail down 10v or from the negative rail up 10v.
U3 - LM211
The gates are driven from the positive rail down 10v or from the negative rail up 10v.
Connect a 10k resistor between pin 1 and pin 2 of the TL072. Drive a sine wave of ~100Hz into the amp. That should allow you to see audio out of the TL072 and into the LM211. The output of the LM211 should be a square wave. That square wave should also be seen at the output transistor gates (driving +/- from the rails).
I soldar a resistor from pins 1 and 2 of tl072, and no signal was present. I then de solder the 10k ohms resistor and all signal are present. I'm using the +- rails voltages as reference.
Generally, if there is no feedback (amp not fully functional), you won't get any audio out of the TL072. That's what the 10k resistor is for.
Without the resistor, did you get drive all of the way to the output transistors?
Without the resistor, did you get drive all of the way to the output transistors?
All signals are present? But when I solder audio MOSFETs one shoulder is still getting hot.
Any suggestion? Or schematic?
Any suggestion? Or schematic?
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