DeadlySones

iTrader: (4)

I have an Atomic 7K. It was bought used, been previously repaired, and run at lower than rated loads. My teammate also bought one from same background.

When I first got it, it ran fine for about 1.5 months @ .5ohms. I didn't really have to turn it up much, and it never got anywhere near hot enough to go into protect.

My teammates decided to wire theirs to a .5 ohm load as I wasn't having any problems after a few weeks and they have much more reserve power than I do. Theirs went into protect the same day, they reset it, and it worked for a bit, then went back into protect again. When they reset it for the second time... "pop" and a spark.

No more protect, or power on.... dead. After taking it all apart, we found 2 FET's that have "popped". Not melted, but rather the center area (where the part info is) literally is popping out, which in turn causes a short. One on each side of the amp.

Now a few weeks later... mine started to act up. So, I rewired to 2ohms, hoping that it was simply the load... worked for a couple days then BAM... into protect... so I reset it hoping nothing bad would happen and it worked fine for most of the rest of the day. Then, that night, it went into protect again, so I went back there... amp was cold, protect light was on... reset deck, and it turned back on... worked for 3 more days, then it did it again, so I pulled it out before it blew hoping to save it. After removing the board I found that the FET's had NO di-electrical grease behind them at all. So I put over 15 grams of heatsink compound on the 74 FET's. Reinstalled the amp, and it worked perfectly for over 4 days till last night. I went out... it went into protect, I reset deck... and POP!! There goes 3 of my Output FET's and 2 are cracked the amp same section as the twins, but not exactly.

I know I need some new FET's. I've tested the gate resistors and they are not within tolerance for proper resistance. So I need to replace a few of them too.

What else should check for? I was told the toriods or possibly the rectifier. I know there is plenty of knowledge on here, combined with my abilities I'm sure we can fix this so I don't have to send it all the way to Atomic.

What you guys think are causing these FET's to "POP"?

Here are some pics. Thanks in advance for your input.

AB FTW

Here is the first question:

Why would you guys just keep resetting your decks? There is a reason why the amp was going into protection.

When you knew your amp was acting up why bother even running it?? You could have done a lot more damage and the in return could cost you a lot more to get fixed.



Your voltage might be up but the current going to the amp is probably low. Was there really a need to run the amp at .5 ohm daily????

Jwb_Spl

iTrader: (2)

Paul I hope you know what your doing. One mistake could take out the whole amp. I would hate to see that happen when your amp isn't completing blown right now.

DeadlySones

iTrader: (4)

My uncle would have this diagnosed in an hour, but unfortunately he passed away several years ago. I'm somewhat electronically inclined. With the right help, I'm sure I can fix this for much less than sending it to Atomic.

Thanks for your help guys, but I need someone to chime in that has electrical background who can help me. I'm a little sharper than I look... and have a little electrical background. I just need to know what I should be looking for that is not melting these FET's but rather "popping" them. I believe my problem lays there. Something is making them pop.

Mine popped running @ 2ohms. I'm taking mine apart again right now, looks like several on one side of mine went.

StillPlayinLow2

maybe the problem happened dailying the amp at .5 on limited current?

those amps should draw well over 700 amps at .5 ohms...1 batterie under the hood and one in the back cant support that daily...burps, yea...but thats a whole diffrent world.

Jwb_Spl

iTrader: (2)

Fets pop.......thats why you hear that pop pop pop sound when an amp blows

DeadlySones

iTrader: (4)

My amp was turned down greatly, I'm sure it wasn't making power. Even if it did, and it was my problem something is damaged/fatigued and needs to be replaced. I just need to know where I should be looking, as I'm not completely knowledgeable on what would cause these to "pop".

Plus the twins have 6 batts and theirs popped first, in the same day. Mine ran for almost 1.5 months. I'm not yet convinced current supply was the issue.

StillPlayinLow2

todd, but thanks for comming out. just cuz im in the same club and we talk doesnt mean anything.

DeadlySones

iTrader: (4)

I understand that Jesse, lol. but something makes them pop... just like other things cause them to melt.

I might also want to add that these amps did this when turned very low, low volume level, or when switching tracks (in the twins case). I just need to know what to test that would make them pop.

StillPlayinLow2

low volume would be less rise, and the amps would actually see a real 1/2 ohm load.....i personally dont know what in the amp would be broken, but the cause is obvious. they were not designed to do .5 ohm daily on limited current.