lol, now I have a problem

[djgizmo]

Summary: Alpine-MRV 545 - 4x20amp fuses pop each time power & ground is connected to amp.


ok, a few weeks ago my amp stopped turning on. I didn't think anything of it since I was so busy, figure the ground just slipped.

I tried working on it today and everytime i attempt to connect power to the amp, the 20am fuses pop. So I figure, its probably a speaker grounded. So I disconnect all the rca's and all the speakers from the amp. Try again, POP, another fuse pops (right now I'm trying them 1 at a time since I popped 4 already) The instant I connect power, the fuse pops.

I figure its might be the remote wire. Pull that, try another fuse, POP. Ok, so then I pull the ground out of the amp, connect up the wire. No pop. (of course)

I'm not sure whats causing this. Any ideas?

[P057]

that shit is getting expensive.

[djgizmo]

lol, no shit. spent about $4 in fuses already. Any ideas?

[P057]

Originally Posted by djgizmo

lol, no shit. spent about $4 in fuses already. Any ideas?

if i did i would have posted something other than that obvious statement. Sorry dude.

[the727kid]

Your amps gone.

[Notladstyle]

I was reading around after you called, the amps powersupply caps will pull a massive amount of current when it is first plugged in, make sure you have all four? fuses in before you connect the power line - GROUND FIRST.

also disconnect the RCA lines, and check for 4ohms at the subwoofer - bridged isnt 2ohm stable and I cannot remember if you purchased the 4ohm or 2ohm when we installed it!!!!

[GradeA_TireFryer]

amp is toasty

[djgizmo]

Ok, I'll try hooking up all 4 fuses. (hopes it doesn't blow all 4 at the same time)

I can't find the manual off the net for the MRV 545 (at work right now). I THINK i still have the manual in my filing cabinet. Since the caps will pull a massive amount of current when its first connected, do you recommend upping the fuses to 25amps? (vs 20) Granted the second the 20amp fuses pop currently, its not a lil pop, you can see where the metal melted inside the fuse (at the popping bridge)

I'll leave everything else unplugged and try your suggestion. all 4 fuses, then ground, then power. I bought it from a reputable online store (local places wanted to charge double to 2.5x as much), so hopefully they'll be able to do a warranty exchange. (surprisingly they still have this amp in stock)

Originally Posted by NoTLaDStyle

I was reading around after you called, the amps powersupply caps will pull a massive amount of current when it is first plugged in, make sure you have all four? fuses in before you connect the power line - GROUND FIRST.

also disconnect the RCA lines, and check for 4ohms at the subwoofer - bridged isnt 2ohm stable and I cannot remember if you purchased the 4ohm or 2ohm when we installed it!!!!

[djgizmo]

Well I looked at the amp, didn't see any 'sticker' that showed void if removed. So I cracked her open. 38 screws later I find this. Seems that water got in the amp (think it happened during a car wash and my trunk of course leaks... DAMIT!) and looks like it blew a mosfet, but since I'm no electronics expert wanted to ask you guys.

Also, I heard that ESS in NPR does amp repair, anyone have their number? If anyone else is willing to repair that chip, I'm also willing to bring it to them if the price is fair.

[Notladstyle]

wheres the heatsink?

[GradeA_TireFryer]

looks lie he unscrewed it from the heat sink - told ya - toasty

[Notladstyle]

I see heat stress on the board - cut your losses and replace the amp.

[djgizmo]

read ABOVE! I unscrewed everything and pulled it out. AKA HEAT SINK NOT GOING TO BE ATTACHED while its out.

Originally Posted by GradeA_TireFryer

looks lie he unscrewed it from the heat sink - told ya - toasty

[djgizmo]

Dalt, its a $15 mosfet chip thats blow, thats all, why throw a $350 amp away because of a $15 repair. I'm willing to pay $60 if someone is willing to do it, but theres no way I'm going to trash it. Dalt, for a person who's going for their electrical engineering degree, its not a really a 'can do' attitude. Shit, if I had the needed soldering skills (still don't, probably won't till after this is fixed of course) I'd fix it myself.

Its not heat stress on the board, its stupid corrosion from the dam water that got in the amp and dried.

[Notladstyle]

Originally Posted by djgizmo

Dalt, its a $15 mosfet chip thats blow, thats all, why throw a $350 amp away because of a $15 repair. I'm willing to pay $60 if someone is willing to do it, but theres no way I'm going to trash it. Dalt, for a person who's going for their electrical engineering degree, its not a really a 'can do' attitude. Shit, if I had the needed soldering skills (still don't, probably won't till after this is fixed of course) I'd fix it myself.

Its not heat stress on the board, its stupid corrosion from the dam water that got in the amp and dried.

Whether it be heat stress or corrosion, every other component on that board, the solder joints, and the board itself have all been stressed and probably damaged

You might get it working with a quick FET swap, but it will be not the last of your problems...

Tis the way with technology.