hi,
The above mentioned subject amplifier had blown power supply mosfets. Some of the resistors near to MIC4424 chip were blown also. If anybody can assist me finding the values will be highly appreciated.I am attaching pictures. Thank you.
Best Regards
Imran
The above mentioned subject amplifier had blown power supply mosfets. Some of the resistors near to MIC4424 chip were blown also. If anybody can assist me finding the values will be highly appreciated.I am attaching pictures. Thank you.
Best Regards
Imran
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Yes other side also in a same condition. actually inductor short and the outputs and powersupply fets gone, i have to remove all to see how many survived. i dont know if the customer will like to fix this amp, it will cost so much to fix. finding inductor is also another problem.
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The inductor can be re-wound.
In a similar amp the resistors are 24.9 ohms but in this amp, the diodes are not used. In your amp, the resistor may have been higher. You can probably go as high as 100 ohms. Double-check operation by forcing the duty cycle to as high as it will go and confirm that the current draw doesn't increase when the duty cycle increases.
Maybe someone else will have more definitive information.
In a similar amp the resistors are 24.9 ohms but in this amp, the diodes are not used. In your amp, the resistor may have been higher. You can probably go as high as 100 ohms. Double-check operation by forcing the duty cycle to as high as it will go and confirm that the current draw doesn't increase when the duty cycle increases.
Maybe someone else will have more definitive information.
100ohms looking stable.
I am unable to get FB4710, is there any alternative that i can use for this amp?
This one uses Class D IC IR21844s.
I am getting trouble winding the coil. it is overlapping and i cant do it so tight to touch the core. i am attaching the picture. please let me know if this will work.
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when i reduce the voltage to 10.5v the oscillations are good and it is not pulling any current. as soon i increase the voltage to 13.5v the amp is drawing current and mosfets getting hot. all this is without main rectifiers.
It is the inductor causing problem. I thought only one inductor was bad but actually both of them had short. Now trying to wind the other one. Very tough job.
hello sir,
i took out the inductor rewind it and after installing it, the current pull did not reduce. but without that inductor the amplifier comes on good. there is also audio signal on outputs.
I found one resistor which is in series with 100uf capacitor which is then connected to one inductor output side was open. and the resistor has no value on it. Can you please suggest the value. its a big resistor R8. Thank you.
I dont feel the power supply has any problem. but there are many other problems. I found Q23 open on all legs. and i dont know the number on it. Q24 is 2N5060. i am attaching the picture. if anybody know about Q23 please let me know. thank you.
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