MREZSTREET
I have set up a lil place to start playn with dead amp I get...I like to tinker with them and try to fix them. Got a few old mid/late 90's Soundstream amps. 1 had the FETS burnt....just was thinking...what makes em pop? I would love to get better at the amp repair and my lil brain always thinks...how did this break and can I make it tougher
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AmmoJammo
often they are damaged by static electricity when the device is being assembled.

it works fine for a period of time, but eventually fails.

the answer is to handle the components properly when fixing it
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MREZSTREET
Amps around 15 years old so I'm sure they were put in right. Back when Soundstream was Still hand crafted in the stated w/pride. From my reading sounds like the protection system wasn't fast enuff. But I'm just getting started at this so I'm probably wrong. Lol
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casperskafs
I had fets burnt in mine (XXX 6500) when I got it. Guy who gave it to me accidently hit 22 volts. This was only one problem among many of course. Amp repair center fixed it for $250
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D-Bass
If it's power supply fets in old push-pull amps, quite often it's cause by running the amp at low impedance. The extra current load can kill the fets and gate resistors. Be sure to replace all in the group, not just those that look damaged or read a short. They can often be leaky and surely have been overheated as well. Replace the resistors as well, even if they read ok out of circuit. The other side of the power supply might be fine, but I usually replace them as well.
Another common way to cook them is under-voltage and too small of power wire. Low voltage means the amp may gather more current, increasing heat. If things get unstable bridges may collapse.
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MREZSTREET
Is it a bad idea to put beefer 1's in as I replace them?
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D-Bass
depends on the fets themselves.

that's like asking, if my car is low on a fluid, can i refilled it with a different fluid? yes, but there are a million different types of fluid. if it's oil, you can use a different oil. but not all oils. too vague.
I typically try to find exact replacements, or as close as I can find. Old eclipse amps can be a bitch because not all the fets are available. for one of my eclipse amps, I found a fet with correct specs, but it has a metal backing. If I attach it to the heatsink it blows the main fuse. I added a small heatsink directly to the fet and an insulated mounting bracket and it works fine. Not ideal, but it works on such a small amp
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MREZSTREET
And its 400 watts so its not ganna be beefy
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doc289
FETs are gates...
Changing the Fets for bigger wont have an impact.
Keeping in mind that the input components of the amp are not going to deliver more juice to the
bigger fets..

Also bigger fets may handle more current, however
The weakest link on the chain, its going to be resistors or diodes...that were not design to work with those bigger fets.
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