MTX RT4240 - Easily fixed

Dr Zeus

2010-10-17 5:12 am
I wanted to give this little 'big' guy a shout out for getting repaired. I dont think this amp is worth all that much; but its a good thing it didnt take that much to fix it. I bought this amp from a local Flea Market on Saturday for $5. Its a 40x4 @4 ohm and 60x2 @2 ohms with 1% THD; so its not really the best or cleanest of amps by any means. Luck would have it as this amp only costed me $0.15 cents to fix so I give it some credit. I guess its worth much more than $5.15.

I'm not sure what the original numbers were on this Diode, but; it was surely needing replacement as it disintigrated into my hands - blown. I didnt want to harm anything much around it so I only replaced it and nothing else. The next door resistor measures out fine as does the electrolitic cap. As far as the rest of the amp; well, the two main caps in the center are -ok- but probably need replacement. I'm not sure if its worth replacing them for the rest of the amp I feel is only mediocre. I'd say its about a 3 out of 10 in terms of strength for 40w/ch amps. It only has 2 Power supply fets.

I replaced this part with a spare 1N4004 and now the amp seems to be working just fine.




I wouldn't call it a beast but surely it puts out around 300 rms when loaded at 2ohms into every channel. Every mtx amp I've seen has been under rated. Don't let the two mosfet supply fool you, it doesn't take many of them depending on circuit design. You got a killer deal on that thing.

Maybe I should finish the Blue Thunder pro3002, I got it working with the irfz44s in the power supply and now I can use the upgrades Perry suggested. Its a beast, underrated at 600watts rms bridged into 4 ohms. I will need another fan though, accidentally touched it when testing and the blades shattered. (slowly walks away...)
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