Something happened to my amplifier the last days, Is an Infinity 475A 4 channel amp.
It started with this, the fuse that goes from the battery to the amplifier, blowed, I dont know why, So i replaced it, and the amp started working again, the problem I saw some days later, is that the amplifier delayed 2 or 4 seconds to start, I have 2 amplifiers the Infinity 475a 4 channel for speakers, and the infinity 1300a for a subwoofer i have, and they alwas start at the same time, but 1 or 2 days later after the fuse blow, it started doing that, then what it happened, is that randomly was entering in protection mode, but I thought that it was the ground that it was well scracthed or something, cause removing the ground cable and putting it again resolved the problem each time. The protecting problem was more frecuent each day, until today that it works randomly, what i mean is that sometime it starts and play for some minutes, and then it stops and enter in protection mode, about 13 seconds later it starts again for 2 seconds, and then it enter in protection mode again, and its like that for hours, 13 seconds in protection mode, 2 working fine, 13 secoind in protection mode and it keeps in that way.
I took some photos of the amp, i checked it the surface and it doesnt appear to be something burned.
Im uploading the photos cause they are big :S
Hope that you can help me!
Sorry for my bad english :/
It started with this, the fuse that goes from the battery to the amplifier, blowed, I dont know why, So i replaced it, and the amp started working again, the problem I saw some days later, is that the amplifier delayed 2 or 4 seconds to start, I have 2 amplifiers the Infinity 475a 4 channel for speakers, and the infinity 1300a for a subwoofer i have, and they alwas start at the same time, but 1 or 2 days later after the fuse blow, it started doing that, then what it happened, is that randomly was entering in protection mode, but I thought that it was the ground that it was well scracthed or something, cause removing the ground cable and putting it again resolved the problem each time. The protecting problem was more frecuent each day, until today that it works randomly, what i mean is that sometime it starts and play for some minutes, and then it stops and enter in protection mode, about 13 seconds later it starts again for 2 seconds, and then it enter in protection mode again, and its like that for hours, 13 seconds in protection mode, 2 working fine, 13 secoind in protection mode and it keeps in that way.
I took some photos of the amp, i checked it the surface and it doesnt appear to be something burned.
Im uploading the photos cause they are big :S
Hope that you can help me!
Sorry for my bad english :/
Here are the images:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Something more i noticed, when I remove the ground the indicator alternate blue-red very fast, when I put the ground it goes blue but 2 seconds later is protected again, not sure if this info tells something, again sorry for my bad English
Does it show the same symptoms with no RCAs and no speaker wires connected to the amp?
Don't remove the ground from the amp while is has power applied.
Don't remove the ground from the amp while is has power applied.
It doesn't make any difference, I tried to shake it to see if something wasn't well soldered o something and I dont see any difference, it works randomly
Does temperature make a difference? If you heat the board with a blow dryer or a heat gun, will it make the problem better or worse?
The temperature of the heatsink isn't generally important. Temperature changes the electrical characteristics of components. Components that are borderline-defective can fail to do their job as they heat/cool. You'd need to heat the entire inside of the amp to see if anything changes. If it does, you'd then have to let it cool and heat smaller areas to try to narrow down the area where the defective component is located.
I picked up one of these amps today dirt cheap. the previous owner broke off 2 of the RCA jacks for the rear channels. I was able to easily fix that and I have to say I am somewhat impressed with the amp! I was able to find schematics only easily, the amp is all discrete for the amp section and it passed bench test's quite well!
I was able to get over 117 watts out of one channel at 4 ohms at 13.7vdc and 97w x2 at 4 ohms all at 1% distortion. I don't have 4 load banks but it looks like it would pass 75x4 easily.
what impressed me is the way it clipped, very very cleanly, no evidence of any instability at all!
it definitely can suck the power! with 2 channels running at clip, it was drawing 30 amps from my supply. all four channels running and yeah I can easily see it drawing 60 amps! the service manual says 65 amps max and they have 2x 35 amp fuses installed.
What made me laugh however is the listed damping factor of 6!!! yup SIX LOL! not much for low end control now is it hahahha!
I was able to get over 117 watts out of one channel at 4 ohms at 13.7vdc and 97w x2 at 4 ohms all at 1% distortion. I don't have 4 load banks but it looks like it would pass 75x4 easily.
what impressed me is the way it clipped, very very cleanly, no evidence of any instability at all!
it definitely can suck the power! with 2 channels running at clip, it was drawing 30 amps from my supply. all four channels running and yeah I can easily see it drawing 60 amps! the service manual says 65 amps max and they have 2x 35 amp fuses installed.
What made me laugh however is the listed damping factor of 6!!! yup SIX LOL! not much for low end control now is it hahahha!
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