blown Rockford amp help

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Okay, i just purchased a Rockford Fosgate Punch 150a2 and was pretty excited to have one of these and went ahead and hooked it up in my ride and it sounded horrible and popped open the cover and saw that it had a severely blown MOSFET in the power supply section. I can't indentify it because it is badly burned. But, then in the cirstui board it says 120.2??? it has a sticker on the power transformer saying 120.2. Does anyone have one of these? i need to know the MOSFET # to try and fix this. I was gonna request an refund from the seller but i'd rather keep it. Kinda dissapointed but oh well. Also how was this still playing music if it had a blown MOSFET? Is this really a Punch 120.2 or Punch 150a2? I'm sorta confused? Thanks
 
It has two identical power supply FETs. If you can read the other, you'll know the part number of the burned one. Replace them both.

The gate resistor for the burned FET is likely open or out of tolerance.

Sometimes, driving only half of the primary windings will allow the amp to play but it will be at reduced power and the supply will draw more current than it normally would.
 
It has two identical power supply FETs. If you can read the other, you'll know the part number of the burned one. Replace them both.

The gate resistor for the burned FET is likely open or out of tolerance.

Sometimes, driving only half of the primary windings will allow the amp to play but it will be at reduced power and the supply will draw more current than it normally would.

Okay i have a question? How do i take the mosfets out? They are soldered on to a smaller circuit board?

And do you know where they sell these mosfets?

Thanks Perry!
 
You'll have to hold the flame on the bottom of the insulator for 30-60 seconds. Be sure to wait until the solder has melted. When the solder has melted, the transistor will pull away from the insulator with very little force (only the force required to bend the component leads).

Be sure to angle the torch so that no heat is applied to the circuit board.

Don't forget to order the gate resistors. If you don't have any on hand, order the driver transistors also (mmbta06 and mmbta56).
 
You'll have to hold the flame on the bottom of the insulator for 30-60 seconds. Be sure to wait until the solder has melted. When the solder has melted, the transistor will pull away from the insulator with very little force (only the force required to bend the component leads).

Be sure to angle the torch so that no heat is applied to the circuit board.

Don't forget to order the gate resistors. If you don't have any on hand, order the driver transistors also (mmbta06 and mmbta56).

Okay so will there be enough solder for the FET to solder back on?

Whichs ones are those?

I got a question? What is CR1, CR2? Are those transistors?
 
CR1/2 are rectifiers.

I'm not sure which board you have but the drivers are typically designated Q1, Q2, Q4 and Q5. They are likely marked 1a and 2a. They will be near the TL494 IC.

You'll have to tin the backs of the transistors with new solder. You'll have to sand the backs of the transistors so they'll take the new solder quickly. The HUF75339P3 is another possible sub and may not need to be sanded to take the solder.
 
CR1/2 are rectifiers.

I'm not sure which board you have but the drivers are typically designated Q1, Q2, Q4 and Q5. They are likely marked 1a and 2a. They will be near the TL494 IC.

You'll have to tin the backs of the transistors with new solder. You'll have to sand the backs of the transistors so they'll take the new solder quickly. The HUF75339P3 is another possible sub and may not need to be sanded to take the solder.

What do you mean by tin them? I'm sorry for these questions, I have very little knowledge on how to fix these.
 
You'll have to apply a thin layer of solder to the back of the transistor.

Hey, i have some more questions about this amp? I ordered the new power supply transistors and the resistors. Now my question is are "CR1" & CR2" transistors as well? I took this amp to my Electronics class and my teach said i had to replace all four transistors. But i see "AKA" "KAK" stamped on these transistors. This leads me to thinking these are rectifiers? If im correct? and even if they are do you think these are possibly shorted? Because the amp did play music somehow. lol

Thanks Perry for your help.
 
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