Couple of weeks ago I was doing some work on my system and accidently made contact between the sub output wires. It happened before, and the amp has gone into protect, but this time it stayed in protect.
Pulled the board out and found a bad IRF640 mosfet in the class D section. There are two IRF640 side by side and I replaced both. Connected the amp today to test, it turns on fine but I can barely get any audible sound from my subs or the mains. It does not matter which rca jacks I plug into, the output is the same. The amp also stayed cool to the touch. Its almost like the am is kinda turning on but not fully?
On the same row as the IRF640s there is also 4 or 5 IRF9640s. I did not replace those. I feel like I have partially fixed it but obviously something else is still wrong. Again, amp turns on but volume is very low, adjusting the gains and volume does increase output be only by a very small amount.
Thanks.
Pulled the board out and found a bad IRF640 mosfet in the class D section. There are two IRF640 side by side and I replaced both. Connected the amp today to test, it turns on fine but I can barely get any audible sound from my subs or the mains. It does not matter which rca jacks I plug into, the output is the same. The amp also stayed cool to the touch. Its almost like the am is kinda turning on but not fully?
On the same row as the IRF640s there is also 4 or 5 IRF9640s. I did not replace those. I feel like I have partially fixed it but obviously something else is still wrong. Again, amp turns on but volume is very low, adjusting the gains and volume does increase output be only by a very small amount.
Thanks.
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. Well it looks like I did fix the amp. Turns out I didn't cross the wires, but there was a short in the line going to the sub. I figured this out when I disconnected the (-) terminal on the amp for the subs. The mains played fine, except for some alternator whine that was not present before. Then I noticed that I was getting some output from the subs despite the fact that the (-) terminal was disconnect at the amp . So I went through all the wires and sure enough there was exposed wire grounding itself to bare metal near my gear shift. Fixed that and all is good!My amp is working still after the repair, and I am finally getting around to my install. However, I have noticed an audible hum in the repaired class D section. It could be it was always there, and its just normal for the amp and I never noticed. But I thought maybe it had to do with the repair?
Other 4 channels are clean, its just the class D section. Running at 2 ohms to two subs. Adjusting the gains makes no difference. Car running or off, makes no difference. Source unit is Note II with stock internal Wolfson DAC running off battery power only.
Any thoughts? Thanks
Other 4 channels are clean, its just the class D section. Running at 2 ohms to two subs. Adjusting the gains makes no difference. Car running or off, makes no difference. Source unit is Note II with stock internal Wolfson DAC running off battery power only.
Any thoughts? Thanks
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