FET substitution question

spooney · 24th April 2010, 07:10 PM

I have an old Advent PA250 amplifier here. A couple of the power supply fets were open and a couple of the gate resistors were charred but somehow it still appeared to work ok. Anyways its clearly not right so I'd like to change the fets and gate resistors without spending any more money than I have to. I have IRF3205 and RFP70N06 on hand as well as 22 ohm and 100 ohm gate resistors. Will any combination of these work to replace the original IRFZ34N's with 100 ohm gate resistors. If anything I'd rather just buy resistors if need be

Perry Babin · 24th April 2010, 08:41 PM

From what I can see on the ampguts photos, it appears that they're using a PNP pulldown transistor so you should be able to use either of those FETs with the 22 ohm resistors.

24th April 2010, 07:10 PM	#1
spooney diyAudio Member Join Date: Dec 2006	FET substitution question I have an old Advent PA250 amplifier here. A couple of the power supply fets were open and a couple of the gate resistors were charred but somehow it still appeared to work ok. Anyways its clearly not right so I'd like to change the fets and gate resistors without spending any more money than I have to. I have IRF3205 and RFP70N06 on hand as well as 22 ohm and 100 ohm gate resistors. Will any combination of these work to replace the original IRFZ34N's with 100 ohm gate resistors. If anything I'd rather just buy resistors if need be

24th April 2010, 08:41 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	From what I can see on the ampguts photos, it appears that they're using a PNP pulldown transistor so you should be able to use either of those FETs with the 22 ohm resistors. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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