Need help finding parts for car amps

[chipper]

Does anyone know where I can find BUZ103 and MTP75N05HD by Motorola MOSFET?

I'm not sure what brand the buz is? But the other is by motorola.
I need some help finding these transistors. Thanks

ohh yeah these are for some Rockford punch amps.
And I need to find the small resistors in a punch 225. Not sure what's the tolerence. They are located next to the supply transistors by the middle leg I believe?? Thanks again

[Perry Babin]

For the BUZ103, if it's used in the power supply, I'd use an IRFZ44 as a sub. There are 4 power supply FETs and 4 gate resistors.

When you order parts, I'd recommend that you also order at least 10 each of the MMBTA06 and MMBTA56.

For the 75N05, I'd use either an IRF1010E or an IRF3205. What are the markings on the gate resistors for this amp? What is the model number of this amp?

[chipper]

Originally Posted by Perry Babin

For the BUZ103, if it's used in the power supply, I'd use an IRFZ44 as a sub. There are 4 power supply FETs and 4 gate resistors.

When you order parts, I'd recommend that you also order at least 10 each of the MMBTA06 and MMBTA56.

For the 75N05, I'd use either an IRF1010E or an IRF3205. What are the markings on the gate resistors for this amp? What is the model number of this amp?

The two amps I'm working on are punch 225.2 and punch 150a2, aside from that I don't think anything else is damaged in the punch 150a2 because it works even though one of the supply fet is toasted. The punch 225 does not work and popped the new fets which were irfz44s. How I did notice one of the small resistors is burned off next to Q6. Do you think D11, D2, D3, D10 are possibly damaged? Or what abot Q2 Q1 Q5 Q4 I'm assuming those are the driver transistors? They are very small and are intretated into the circuit board.

[Perry Babin]

When doing repairs, you should have all semiconductors tightly clamped to the heatsink and have a small fuse (10 amp for these two amps) in the B+ line. Then, if there's a problem, the fuse will blow and the new semiconductors will survive (in most all cases).

The diodes near the FETs rarely ever fail. Those transistors are the drivers. The ones marked 2a are the ones that fail most often when the power supply FETs fail.

Faults in the audio section of the 225 could have caused the power supply FETs to fail again but the most likely cause is defective drivers or defective gate resistors.

[chipper]

So can I check the driver transistors while in the circuit? And do you know the resistance for the gate resistors? And is I get this to turn on would I have to bias anything?

[Perry Babin]

With only remote and ground connected to the amp (no B+), measure the DC voltage on the first leg of each of the 4 FETs (defective ones removed from the circuit). What do you read?

What are the markings on the gate resistors?