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?

[POST]

that shit is getting expensive.

[djgizmo]

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

[POST]

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)




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.

http://www.monstertunes.net/download/photos/ampchip.jpg

[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.

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]

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.

[djgizmo]

Stressed? Like hundreds of people don't 'stress' their systems on a DAILY basis by over cranking their systems, or going to low in ohms. If they blow out a power supply in the amp, say they spend $1000 on the amp, there's no need to replace the entire amp.

Yes, its a hassle. Yes, buying another one is EASIER, but bottom line, repair comes in at wayyyyy lower cost. Guess I'm on my own on this one.

I'm seriously surprised that no one knows of a decent repair shop. Amp repair used to be a huge money maker up north.

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.

[Notladstyle]

Theres a difference between pushing the thermal and electrical limits of an amp and maybe sending it into protect for 15 seconds and exceeding those limits to the point a high speed pnp mosfet actually welds itself together.

How long have you spent troubleshooting/disassembling it? Isn't your time worth money? Do you put value on not having any music in your car while you wait to repair it? What is the depreciated value of the amp? it was manufactured in 05 right? Is there better technology for cheaper available today?

I'm not saying I know it all, but I've been called out to diagnose a modest number of amps, and FET damage is never cheaper to repair than replacing the amp.

If you are set on repair, at least send it back to Alpine. No one else will know exactly what to check and repair - remember that amp is all digital. They repair most issues for a flat $140 fee last time I checked and they ship it back to you. If its under warranty you will get away with just shipping charges.

[djgizmo]

I've spent about 2 hours give or take 10-15 min. so if I price my self @ $15 and hour, about $40 so far, including dissembly of the amp. If I get the chip for $15, and say $50 for someone solder it on for me. Say another 2 hours for me to put it back together, $30, so instead of replacing it for $350, it'd be about $135 in theory, but in reality, it'd only cost $65 less than 20% of the amp replacement cost.

I would normally do the warranty, but the second they'd see corrosion inside the amp, they'd call it abuse in a heartbeat.



I'm not saying I know it all, but I've been called out to diagnose a modest number of amps, and FET damage is never cheaper to repair than replacing the amp.

If you are set on repair, at least send it back to Alpine. No one else will know exactly what to check and repair - remember that amp is all digital. They repair most issues for a flat $140 fee last time I checked and they ship it back to you. If its under warranty you will get away with just shipping charges.