Hi everyone!
I have this Focua Acoustics FX-1200D amp, and I´m having a slight problems with it..the amp came to me with 2 blown ampFET´s and the HIP4080 were dead. -> changed all FETs and that HIP, everything else seemed to be fine, but surprisesurprise NO
Amp powers up nicely, but draws excessive current and burns those same two FETs immediately......measured a bit, and there´s a 2,6VDC drive at those FETs they´re at low side. Even if I pull out the HIP, there´s 0,247VDC still.
Now there´s HIP on its place and all other FETs at amp section - amp powers up nicely, green light comes on and output relay clicks BUT there´s a 1,6VDC voltage at output :/
Voltages at HIP:
without IC installed
1: 11.82
2: 12.10
3: 0,000
4: 0,000
5: 0,002
6: 6,27
7: 6,70
8: 0,00
9: 0,00
10: 12,00
11: 0,000
12: 6,52
13: 0,027
14: 0,002
15: 12,08
16: 12,08
17: 0,002
18: 0,039
19: 6,53
20: 0,001
With IC installed on it´s place:
1: 16,52
2: 12,08
3: 0,000
4: 0,000
5: 2,797
6: 6,27
7: 8,05
8: 5,23
9: 5,23
10: 27,38
11: 18,24
12: 15,91
13: 8,69
14: 12,06
15: 12,06
16: 0,000
17: 0,000
18: 2,695
19: 14,15
20: 14,25
I have this Focua Acoustics FX-1200D amp, and I´m having a slight problems with it..the amp came to me with 2 blown ampFET´s and the HIP4080 were dead. -> changed all FETs and that HIP, everything else seemed to be fine, but surprisesurprise NO
Amp powers up nicely, but draws excessive current and burns those same two FETs immediately......measured a bit, and there´s a 2,6VDC drive at those FETs they´re at low side. Even if I pull out the HIP, there´s 0,247VDC still.
Now there´s HIP on its place and all other FETs at amp section - amp powers up nicely, green light comes on and output relay clicks BUT there´s a 1,6VDC voltage at output :/
Voltages at HIP:
without IC installed
1: 11.82
2: 12.10
3: 0,000
4: 0,000
5: 0,002
6: 6,27
7: 6,70
8: 0,00
9: 0,00
10: 12,00
11: 0,000
12: 6,52
13: 0,027
14: 0,002
15: 12,08
16: 12,08
17: 0,002
18: 0,039
19: 6,53
20: 0,001
With IC installed on it´s place:
1: 16,52
2: 12,08
3: 0,000
4: 0,000
5: 2,797
6: 6,27
7: 8,05
8: 5,23
9: 5,23
10: 27,38
11: 18,24
12: 15,91
13: 8,69
14: 12,06
15: 12,06
16: 0,000
17: 0,000
18: 2,695
19: 14,15
20: 14,25
What is the rail voltage?
Are the large 1 0hm resistors near the 4080 within tolerance?
Do you have rail-rail oscillation on the output transistors?
Did you measure directly across the positive and negative speaker terminals or from ground to the speaker terminals?
Are the large 1 0hm resistors near the 4080 within tolerance?
Do you have rail-rail oscillation on the output transistors?
Did you measure directly across the positive and negative speaker terminals or from ground to the speaker terminals?
Last edited:
The resistors I'm referring to are connected between one output filter inductor and pin 12 for 1/2 of the IC and between the other output filter inductor and pin 19. I've never seen them as high as 10 ohms. There is probably another large 10 ohm resistor parallel with a diode (actually a TVS).
Do you have rail-rail oscillation on the output transistors?
Do you have rail-rail oscillation on the output transistors?
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