Memphis Mojo 2000W amp blown power supply

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My friend blew a mojo 2000. looks like missing supports broke a rectifier and mosfet causing the power supply to fail.

i replaced the driver transistors (KTA1266s) and all 22Ohm resistors.

I thought these amps came with IRF3205s in the power supply, this has all IRF1010Es.

Which is the original part or can they be substituted?
 
New rectifier, new irf3205s in, it protects (power and protect lights on), rectifiers out it comes out of protect. are 22ohm gate resistors still right?

there are no shorted outputs (didn't thoroughly check the driver cards, no oscope). it appears that physical damage caused this because a rectifier was cracked in two.

if i let it warm up some w/o rectifiers the two largest resistors on the driver card get warm, not hot at all, just warm. is that odd?

could I check for peak voltages where the rectifiers were so I can tell if it is PS or output?
 
With the rectifiers in, do you see a pulse of DC voltage on any of the 4 output filter inductors just after you apply remote voltage?

You'll need to have the meter connected to the inductor before you apply remote voltage because the pulse could be very short. Monitor the voltage for about 10 seconds for each inductor.

It's normal for the driver boards to run warm.
 
OK! Outputs are as cold as ice! But.... on the inductor side of the rectifiers, diode test sees 001, when you push the inductor one way it opens, the other it shorts. Sounds like the insulation on the inductor wires is worn from heat or vibration. That would explain why only PS fets get hot.

Can I repair this inductor (unwind and patch)? Never patched an inductor, wanted to know if there is a specific method. If not, is it the same inductor that is in the Orion 2500D? I can't afford to fix the orion yet so it can be used for parts for now.
 
don't know if you care but i have to tell everyone. a system I built went to the import face off yesterday. he wasn't going to go but somebody with 12 10s was really running their mouth.

well, my buddy showed up with the system I built for him and beat EVERYONE AT THE SHOW! he averaged 150.2 w/ 6 pioneer 12s and 2 JL1000/1s. took home three trophies including loudest car of the day, street beat, and 1001-2000W. had to post it, very excited. you can see the build at my site TooMuch Audio.

thanks for your help Perry. i'll post again when I have the inductor out. this amp may end up in that car again after all.
 
I've never seen an Orion 2500D with the inductors like the ones in this amp (attached amp is what I assume you have).
 

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sorry, maybe i'm calling it something else. it's the coil with 2 windings between the filter caps, it is electrically between the rectifiers and filter caps.

i found a VERY SMALL short where it rests on two of the leads, i put a few strips of electrical tape in there and solderd it back in. the amp is out of protect and is staying nice and cool, now I will reassemble, check the DC offset, and see if she works. is that stuff just clear silicone holding parts down?

thanks for all your help, this might be a wrap! next time I get a check i'm buying your tutorial, it's high on my list. it's just under rent, electric, and tires.
 
I'm sorry, I assumed that you meant the output filter inductors. If it's connected between the rectifiers and the rail caps, it's the common mode choke (inductor).

The protect circuit was likely triggered due to low voltage or wasn't able to come out of protection because the power supply couldn't power up fully. Generally, the protection circuit indicates that there's a problem in the audio section, but obviously, not always.

They often use clear silicone as a fixative.
 
ok, couple of symptoms.

small amount of ground noise coming out of RCA inputs, when I connect it you hear it on the highs.

shuts down when you turn it up (progressively got worse, I shut it down before anything really bad happened).

goofy pops and clicks happen when you use the QFC knob and it draws a lot of current during these pops.

when i opened it up again the output driver boards were really warm (yes I put the heat transfer pads in), not much warmer than the output inductors. everything else seemed cool. the heatsink is completely cold and I double checked for output shorts.
forgot to check for DC offset after running it to see if anything changed, was only -10mV when I reassembled so I left it for now.

any ideas? I will check all solder joints till then.
 
If it's popping, it's likely swinging the output voltage to the rails. If a speaker is connected, it's going to draw a lot of current (approximately equal to the current draw at full power output).

What signal source are you using?

There could be several reasons for it shutting down. Was the voltage across the B+ and ground terminals dropping below ~11v when it shut down?
 
music source.

my power supply only good to see if it powers up and stays out of protect. i put it in the car with small fuse inline. i really didn't have a way to monitor voltage. i'll run it down to a park (don't want to bother the neighbors) and turn the level down, attach dmm to gnd and B+, turn level up little by little and see what she does. the QFC knob is the only one that causes it to deliver output voltage.

when i power it up with a 5 1/4 inch speaker it has a quiet high pitch squeal (no source attatched) that gets higher pitched as it stays powered on (not alternator noise but sounds similar [the car was not running for this test]). the noise stays the same level independant of the level control.

i'll let you know what the voltage is doing this afternoon.
 
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