Amp wont power up after FUSE blow?? Visonik4000D

[WOT]

Well I dont get why exactly the SECOND fuse blew, I never got to even power the amp up again after I changed it. I guess I have to figure that out first. Power wire shouldnt be grounding out though, it was a perfect run

 

[snoopdan 5,000+ posts]

dude, open up the amp and look on the furthest end of the motherboard opposite side of where you hook up your power wires. Check and see if you see anything crispy around the first 4-6 FET's on each side of the board.

I bet your shit is toast. Remember, ive owned 3 of these amps //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[ultimate157 5,000+ posts]

Check the amp, then look at your power wire. Disconnect both ends of the + run of 1/0 and do a continuity test to ground. this will tell you if the wire is shorted.

 

[WOT]

Is this amp easy to get to the board? I dont see any access from the top, I'll have to pull my install out if I wanna take the amp completely out.

I dont get why the fuse would blow before I even had a chance to power the amp up again though.....

 

[ultimate157 5,000+ posts]

Is this amp easy to get to the board? I dont see any access from the top, I'll have to pull my install out if I wanna take the amp completely out.

Most amps are designed with the heatsink on top and the board secured to it. Access panel is on the bottom.

 

[audioarsonal 10+ year member]

Disconnect the power wire from the amp.Install a new fuse.If it holds the wire isn't shorted.

 

[Rashaddd 5,000+ posts]

check with the car off, do you get voltage across those two wires going to that fuse that keeps blowing?

If you do, either the amp is shorting or a power wire is shorting, and then like someone else said check the resistance of the power terminals on the amp, should be in the thousands of ohms

 

[boomzilla 10+ year member]

dude, that fuse was just wrapped in the split loom with the wires attached?

i bet the fuse grounded out or got water on it and shorted... get a waterproof fuse holder for that thing!!!

 

[WOT]

Ur right I dont have a fuse holder, cause it got smashed when my bud was helping install a second battery, but it was wrapped in tape, then wire loomed, then taped over that....

Im on lunch in 10 min and I'll go try and get all of this done

 

[GMCJimmyslt2000 10+ year member]

why cheap out and not have a fuse holder...ur just asking for ur shit to get fukd, which it just did.

 

[snoopdan 5,000+ posts]

I saw one of these amps blow up this past weekend at a car audio event. I told the guy on a couple of occasions not to let his shit run below 11 volts. he had been powering 6 15's with one of these amps. Now he's listening to his mids //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[Haunz 10+ year member]

^ I have yet to understand how voltage drop could cause an amp to blow... //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

 

[snoopdan 5,000+ posts]

^ I have yet to understand how voltage drop could cause an amp to blow... //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

FET's heat up more when trying to pass the same amount of power thru them at lower voltages. More heat = physical damage to the semiconducting material inside of the MosFet's.

 

[WOT]

why cheap out and not have a fuse holder...ur just asking for ur shit to get fukd, which it just did.

Has nothing to do with cheaping out, I had a holder, it broke, replacment holder and 2 300amp fuses are coming from ebay, the only local audio store we have is future shop. And when I just went to go buy there last 150amp fuse, it was gone......

So now I have to go out of town, just to buy an overpriced fuse, just to test to see if my amp is pooched, I just checked the firewall gronmet (pretty much the only tight spot the power wire might have frayed) and it was perfect.

But I'll get that fuse and report back, and probably unmount the amp and take it apart and post up the pics later tonight

 

[Haunz 10+ year member]

FET's heat up more when trying to pass the same amount of power thru them at lower voltages. More heat = physical damage to the semiconducting material inside of the MosFet's.

wat ? the behavior you describe is quite contrary to Ohm's law..

That amp has an unregulated power supply and the rail voltage and power output is going to be proportional to input voltage.... The amp is not going to pull more current as voltage drops, it's going to pull less...

Even if it was a tightly regulated amp, it would be designed to work reliably with the PSU switching at 100%...