Fet 75339p i need to know the part number of the 4 output transistor of my 421d, i got this amp with missing parts so i need help..

SOURCE: Have a a7 Hc... Blown transistors.. Shematic diagram??

What are the part numbers on the transistors you replaced?

Did you replace transistors in the output section and the power supply section?

Does this amp have the defaced ICs labeled B52 and F16?

SOURCE: Trying to find the right FET to replace burnt up ones with

hafler use international rectifier hexfets. there is alot of confusion what constitutes a mosfet amplifier.
if the outputs are mosfets instead of bipolar transistors, it is a mosfet amp.
some designs are using mosfets to drive the switch mode power supply,but use bipolar output transistors.that is not a true mosfet amp.
you need to go to an electronic supplier for the repair industry.
or the manufacturers warranty depot,who will be able to order them.mosfets are very high current devices,you have to ask ...why did they fail. if they are the switch mode drivers,there is bad capacitors in that circuit

SOURCE: output transistor is out in car amp

Hello nymnym999,

You did not specify which Fusion amp you have but if the insides looks like the Fusion PP-AM60020 image below, you'll have to "desolder" the transistor.


First remove the heat sink from the transistor case. You'll need a controlled heat soldering station, a desoldering vacuum tool commonly referred to as a "solder ******", and some desoldering braid. Be careful with the heat around other components.

After removing the transistor, use the desoldering braid to clean off any remaining solder from around and in the circuit board mounting holes. Position the new transistor and solder it to the board. Put a thin film of thermal compound on the heat sink and remount it to the new transistor. Use just enough of the compound to insure an air-free join between the transistor case and the heat sink. Reassemble the case and you're finished.

Hope this helps.

SOURCE: blown transistor. labeled rect.2

rect. means rectifier and is a pair of diodes or a single diode (if it only has 2 legs). This part is in betwen the power supply and the output rail filter capacitors. If it is blown, the odds are it blew for a reason.. I.E. The amp developed a problem (probably a short in one or more of the output transistors) that caused an overload on the P.S. If the amp could not detect the overload, or it does not have the capability to tell it has a problem, then the P.S. will attempt to deliver all it's energy to the amp regardless of the problem. In that case, something's gotta give. In this case, it was the rectifier. The amp will need to be examined by a qualified technician to determine the actual problem. The rectifiers do not (not usually anyway) fail by themselves for no reason. The actual cause will need to be identified and corrected before the part can be replaced and the amp put back into working order. If you just replaced the rectifer, then it will fail immediately again.

SOURCE: Amp won't power up,anymore! Even with new parts installed,removed

Hiya, dont have a diag either what you will have to try and is compare the left channel with the right. There will be 2 driver transistors (also likely on heatsink) close to the outputs. Check which driver drives which output on the left, then match it on the right. Those same drivers could very well also be a problem on the right as they often go with the outputs. There is a possibilty they have smoked again. See here to test FETS
http://www.4qdtec.com/mostest.html

Basically the left will match the right but not similar locations but definitely by track joins.

Also check the power resistors at the output. Often also go.

Hope that helps