amp repair

[Snowboard_Jedi]

I have a blown mtx 500 watt d class amp, and my friend has an expensive rockford 500 watt 2 channel amp. I tried repairing both of these amps, replacing all 8 transistors in my d class, 7 of which were blown, and replacing 4 transistors in the rockford amp, all 4 of those being melted and obviously blown. Well, I wasn't expecting to make the amps work, but I was hoping, but my hopes were dashed, haha. My D class amp didn't turn on the LED's, so it's still a ways from being repaired. My friend's rockford amp tried to turn on, but didn't work properly, it was just pulsing the speaker a lil bit, then I noticed a lil smoke coming from the 4 power supply transistors I had replaced, so i quickly unhooked the power. I guess the power supply on the rockford amp is blown and is overpowering those transistors causing them to smoke and fry? Do I need to replace the large capacitors? I want to unsolder the large capacitors, and test them to see if they're any good. I figured out how to test transistors, which was a cool skill to learn, and that is how i figured out that 7 of the 8 transistors in my D class amp were blown. But I still got a lot to learn.

years ago i had dreams of aquiring an electrical engineering degree so that I could make a career designing amplifiers for car audio and home theatre manufacturing companies. Well I dropped out of college and am pursuing other career dreams. But I still want to learn how to repair these far too easy to break amplifiers.

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[Spooney 10+ year member]

Car Audio - diyAudio

 

[Spooney 10+ year member]

Here is Perry's basic amp repair page : Basic Amplifier Repair

 

[Snowboard_Jedi]

Car Audio - diyAudio
Thanks much for the reply. I have been reading on the diyaudio, was thinking about posting there too. And I have read about half of the amplifier repair tutorial, need to read the other half as well though. I was just looking at the rockford amp again, and I think I might see a tiny bulge on the top of one of the large capacitors. Hard to tell if it's really a bulge or not, but if it is, looks like a sign it's blown. Maybe new caps would make the amp work, maybe not.

 

[Spooney 10+ year member]

Thanks much for the reply. I have been reading on the diyaudio, was thinking about posting there too. And I have read about half of the amplifier repair tutorial, need to read the other half as well though. I was just looking at the rockford amp again, and I think I might see a tiny bulge on the top of one of the large capacitors. Hard to tell if it's really a bulge or not, but if it is, looks like a sign it's blown. Maybe new caps would make the amp work, maybe not.

The tutorial he sells on ebay is insane. The basic repair pages are nothing compared to that. I bought it a few years ago for 50 bucks. Well worth it

 

---------- Post added at 02:42 PM ---------- Previous post was at 02:41 PM ----------

 

Thanks much for the reply. I have been reading on the diyaudio, was thinking about posting there too. And I have read about half of the amplifier repair tutorial, need to read the other half as well though. I was just looking at the rockford amp again, and I think I might see a tiny bulge on the top of one of the large capacitors. Hard to tell if it's really a bulge or not, but if it is, looks like a sign it's blown. Maybe new caps would make the amp work, maybe not.

The caps are most likely not your issue at this point.

 

[keep_hope_alive Premium Member]

several items are likely in need of repair. transistors are connected to other parts of the circuit which can also fail. simply replacing transistors isn't going to be sufficient.

i agree if you want to learn, you need to get a grasp on the basic EE principals and also invest in good repair information. Perry's tutorials are your best bet. read before you work. understand before you attempt. don't rush it, be patient.

 

[Snowboard_Jedi]

yeah i think sometime in the next coupld of months i will spend 50 on that repair tutorial.