Mosfets

[Boon]

Ok we can immediately exclude the FDP5680 because it can only handle 65w of dissipation and the IRFZ46N does 107w.

Of the ones you linked the NTE is the closest match to the original FETs but the STP fet has higher specs.

The specified replacement from the site I normally use is the RFP70N06 which has higher current and voltage capability than the originals. Costs about $1.80 each I think.

http://mouser.com/Search/ProductDetail.asp...U9z22sxLw%3d%3d

Personally I would get those. If you only order 16 you better hope they're date matched...

All that said, I stand by the fact that if you don't have a scope you're shooting in the dark.

[01xtreme]

Honestly Im not getting that far into it for the fact that A it is a 300 dollar amp, and B. Im just trying to make it to 1 show, then I can blow the fucker up again, and call it a day. Hopefully I will have new amps in the not so distant future, but I really would like to make it to 1 more show before the new amps, and possibly rebuild. Thanks for the input though.

[Forevrbumpn]

my particular PA3000DB was diagnosed by a amp repair guru, he tried to tell me one of the toroids were going bad, but that was BS to get another $100 out of me, but said besides that, it was just the 16 FET's

I' am assuming if my FET's were bad just due to blowing this one sub, and the ohms on the sub set up was dropped down to who knows what ohm, and then POP

I would think that PA just used faulty FETs, should have used something a little better, and seeing how this happened to my amp 1 year ago, and this guy having the exact same issue, not 1 3, 7 FETs, but all in a row seems like faulty designing when amp is put to short

[Boon]

Honestly Im not getting that far into it for the fact that A it is a 300 dollar amp, and B. Im just trying to make it to 1 show, then I can blow the fucker up again, and call it a day. Hopefully I will have new amps in the not so distant future, but I really would like to make it to 1 more show before the new amps, and possibly rebuild. Thanks for the input though.

Not to be a downer but I wouldn't bother. If your drive is bad the amp won't run or will just pop all the fets again the second you put power to it... or it'll work until you run it hard and THEN it'll blow up.

So yeah. Personally I don't think it's worth spending $30 or more on an amp that may actually be irrepairably rooted anyway.

Foreverbumpn, it's hard to say if the toroid really would be rooted... but if your output section is ok I would say they're fine UNLESS the amp blew because the toroid has a short in it.

[01xtreme]

Not to be a downer but I wouldn't bother. If your drive is bad the amp won't run or will just pop all the fets again the second you put power to it... or it'll work until you run it hard and THEN it'll blow up.

So yeah. Personally I don't think it's worth spending $30 or more on an amp that may actually be irrepairably rooted anyway.

Foreverbumpn, it's hard to say if the toroid really would be rooted... but if your output section is ok I would say they're fine UNLESS the amp blew because the toroid has a short in it.

not questioning you at all, but what is leading you to believe the drive is bad? I was beating the shit out of the amp, then POP. started smoking. Im not sure if it helps determine anything, but the amp still turned on and the fan would run, but it just made no sound.

Edited December 4, 2008 by 01xtreme

[audiofanaticz]

Boon hit everything on the head. There is always a reason the fets go, usally one 1 goes a lot go, AND ALWAYS TAKING OTHER THINGS WITH THEM.

The Higher voltage/ more expensive fets would be a better buy then the el cheapos if you do decide to buy the new fets.

But without the proper testing gear, it dont even pay. Send it in and pay for a repair, or take the board out the amp, and scrap the heatsink out for aluminum and buy new.

[01xtreme]

Boon hit everything on the head. There is always a reason the fets go, usally one 1 goes a lot go, AND ALWAYS TAKING OTHER THINGS WITH THEM.

The Higher voltage/ more expensive fets would be a better buy then the el cheapos if you do decide to buy the new fets.

But without the proper testing gear, it dont even pay. Send it in and pay for a repair, or take the board out the amp, and scrap the heatsink out for aluminum and buy new.

If I had the money to buy a new amp, or pay to have it fixed, I would have never started the thread. Unfortunately, I never break shit, unless I can't afford to replace it.

[Forevrbumpn]

Not to be a downer but I wouldn't bother. If your drive is bad the amp won't run or will just pop all the fets again the second you put power to it... or it'll work until you run it hard and THEN it'll blow up.

So yeah. Personally I don't think it's worth spending $30 or more on an amp that may actually be irrepairably rooted anyway.

Foreverbumpn, it's hard to say if the toroid really would be rooted... but if your output section is ok I would say they're fine UNLESS the amp blew because the toroid has a short in it.

Amps is a weak spot on my knowledge.... I know how to diagnose and repair most electronics, but when it comes to power supplies, Iam about 50/50 on them

I wish I knew how to upgrade the toroid to a higher voltage , and same as the FETs, larger capacitors... I USED to know this guy, who I talked about up there^^^ but he jacked me for $30, so I assumed he just wanted to say the Toroid coil was bad, just to get $200 out of me.- on a $269 amp, no way that was worth it... Perhaps on mine I will take a closer look, and also look up some stuff online about diagnosing, and repairing amps...

Thanks 01xtreme for starting this thread, I forgot I had a amp in the garage that could possible be fixed.. lol

[audiofanaticz]

Unfortunately, I never break shit, unless I can't afford to replace it.

Well thats not the case this time

I have blown many many many amps. LoL

Some either blown because of under voltage, over voltage, crazy low impedance loads, faulty rca's, no protections circuit (sub blew and that took the amp with it), and sometimes just the I dont know what happened Lol

I delt with 3 companies so far db-r, arc, and cia (cia is horrid never again!. A+++ to db-r and arc for pricings, but db-r is a very busy place where the sundowns get repaired first then the consumer sent in amps, youll be waiting a bit for your amp back. and arc is seeming to be very reliable, decently fast, and great price)

But no matter what amp I had in for any repair when I knew the fets where popped, other things needed repair attention too. No amp just ever needed new fets only.

There was a reason that caused your mosfets to get extremely hot, when they get too hot its usally due to being worked to hard, it maybe a clipped signal, it maybe a impedance ohm to low, it maybe that its power acoustik and them being cheaper they used low grade mosfets to keep cost down.

I dont know what else to say, but most likely your gonna end up spending the cash on new mosfets, put them in the amp, get it all back together, power it up, and poof again. Then youll be out more cash.

I would buy the nicest fets you can buy if your still gonna attempt the repair yourself, they will last longer, and most likely make the amp a little more stable.

Also it is wise to replace all mosfets at once. If its the power supply mosfets, replace them all. If its the output mosfets, replace them all.

If theres 6 powersupply fets on the left side of the board, but only 3 are burned you should at least replace all 6, if you cant afford to do all 12 (left and right side).

The reason for doing them all is because you run the chance or risk of having a different date code or brand and date mosfet completely different then what you currently got. If you buy the nice fets and put them in a pcb with the older weaker fets you will get no real gain in spending the extra cash.

Best of luck to you, and hopefully just the fets are actually needing repair. I expect updates and pics, this has the potential for a great do it yourself thread

[E a r t h]

Save yourself the hastle and send it in or buy something else. There are too many different variables when dealing with fets, caps, and the like.