MTX thunder 3401 problem

[FUNGC]

hey guys, im new to the forum and audio repair scene. ive read up the basic repair guide and searched hours on google upon my problem i have with my MTX Thunder 3401 amp.

so the problem is when i start my car it just thumps once, and seems to suck in my sub. can you guys tell me whats wrong with it? thanks!

[Perry Babin]

That's generally caused by shorted output transistors. That's the first thing you need to check. I'm not familiar with this amp (photos would help) but in similar amps, the larger transistors clamped to the heatsink are the output transistors.

Do NOT apply power to this amp unless all of the heatsink-mounted components are tightly clamped to the heatsink.

[FUNGC]

thanks for the quick reply heres a picture of it. i will try to take better pictures of it when i find my camera.

so the output transistors are the two on the left on the heat sink correct?

[Perry Babin]

The 4 on the left of the heatsink.

[FUNGC]

so if i replace these the amp should operate with no problems? and where am i supposed to find these parts?

[Perry Babin]

The first thing you should do is to check them. There could be another fault causing the DC but the outputs are the most common fault.

[FUNGC]

well i checked the output transistors and the side closest to the audio output seems to be shorted, on one side all 3 legs no matter what configuration i do it reads zero and the other one the same thing too.

now the question is the model number of the transistor. it saids IRFP240 and there are other things on it like 424L and 92 and FD. would any IRFP240 transistor work on this amp? and thank you for your quick replies!