HI all,
I got this amp. after replacing all the output fets and IRS21844S IC the amp came on normal. but just after some time. idle current gone too low and SG3525 duty cycle gone too low. i measured voltages and pin1 is 5v and pin2 is 5.1. somebody interfered with the resistor R37 and when measured it was 56k. i am getting voltage on pin9 0.6~0.9v.
green led lits dim and amp remains lower than 0.3amps. sometimes 0amps.
i tried to change the resistor value as 62k ohms then amp goes into protect.
I got this amp. after replacing all the output fets and IRS21844S IC the amp came on normal. but just after some time. idle current gone too low and SG3525 duty cycle gone too low. i measured voltages and pin1 is 5v and pin2 is 5.1. somebody interfered with the resistor R37 and when measured it was 56k. i am getting voltage on pin9 0.6~0.9v.
green led lits dim and amp remains lower than 0.3amps. sometimes 0amps.
i tried to change the resistor value as 62k ohms then amp goes into protect.
Last edited:
If no one has a definitive answer, post good quality photos of the main board and another one of the power supply control circuit.
That's essentially the same as the 4080 amps. Are all of the supply and input voltages on the 3525 remaining OK when the voltage on pin 9 drops?
If you 're getting essentially the same voltage on pins 1 and 2, the duty cycle is OK because the rail voltage is present.
If you 're getting essentially the same voltage on pins 1 and 2, the duty cycle is OK because the rail voltage is present.
I am having all the voltages on 3525. If duty cycle is ok then why is it not pulling no current. What am I missing?
Opamps have input voltage only 8v.
No audio. Before this problem start the amp came on normal and it produce audio.
I think 7v is about right for the positive power supply pin.
I think it's very similar to the 4080 mmats amps which is similar to the 4080 Earthquake amps. See attached if you don't already have something similar.
I think it's very similar to the 4080 mmats amps which is similar to the 4080 Earthquake amps. See attached if you don't already have something similar.
I have similar kind amp and it have 14.5v on opamp positive supply pin. Also this amp has LM340T 15v 7815 regulator.
If either of those regulators feeds the positive supply pin of the op-amps, determine why the regulator circuit isn't producing whatever voltage you think it should be producing.
Eventhough there is voltage on 3525 pin1 pin2 and 0.9v on pin9 there is no voltage on output pins of 3525. Rail voltage may be generating at the starting but then 3525 is not sending pulses.
The regulators that you referred to here:
Also this amp has LM340T 15v 7815 regulator.
Is the output stage completely intact?
Also this amp has LM340T 15v 7815 regulator.
Is the output stage completely intact?
Only one regulator it have. "Lm340t15". 7815 written on it also. And I changed this to see if it was giving trouble. The output section mainly the driver card was removed by some other tech and he spoiled the vias. But when I first on the amp the waveform all look perfect. Then I dont know if any intermittent bad connection exit.
