Cross for the FB21N30D ?

Scanlines · 23rd July 2009, 11:58 AM

I've got this Orion 2500D apart and I need to replace some mosfets. I can't find any data on the FB21N30D.

There are also IRF9640's on the dead channel, I'm assuming that this is the complement of the FB's ? I'm wondering about using IRF640's ?

Dimon74 · 23rd July 2009, 01:48 PM

Orion amp uses IRFB31N20D not FB21n30.You can use there FQP34N20C or FQP32N20C

Dimon74 · 23rd July 2009, 01:55 PM

Replacement for IRF9640 is FQP12P20.You can replace IRFB31N20 with IRF640,but they have almost twice lower current,and higher Rds on resistance.I did that trick in JBL BPX2200.1 which uses same schematic as ORION 2500D but that will decrease capability to drive low ohm loads

Perry Babin · 23rd July 2009, 05:15 PM

Someone sent me an amp with IRF640s in place of the IRFB31N20Ds and the IRF640s would overheat. Replacing them with the (original) IRFB31N20Ds solved that problem. Use the IRFB31N20D. The 9640 and the 31N20 are not complementary but they are the parts the amp was designed to use so that's what you should use when you replace them. Class D amps are a bit finicky when it comes to the outputs. If you ever want to experiment with different outputs, get the amp working properly with the original parts then try the subs.

http://octopart.com/parts/search?q=IRFB31N20D&js=on

Scanlines · 23rd July 2009, 06:38 PM

Thanks guys, I will use the originals and I see they ARE available.

Sorry about that, I inverted the 2 and 3 when I wrote it down.
My apologies.

23rd July 2009, 11:58 AM	#1
Scanlines diyAudio Member Join Date: Dec 2007	Cross for the FB21N30D ? I've got this Orion 2500D apart and I need to replace some mosfets. I can't find any data on the FB21N30D. There are also IRF9640's on the dead channel, I'm assuming that this is the complement of the FB's ? I'm wondering about using IRF640's ?

23rd July 2009, 05:15 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Someone sent me an amp with IRF640s in place of the IRFB31N20Ds and the IRF640s would overheat. Replacing them with the (original) IRFB31N20Ds solved that problem. Use the IRFB31N20D. The 9640 and the 31N20 are not complementary but they are the parts the amp was designed to use so that's what you should use when you replace them. Class D amps are a bit finicky when it comes to the outputs. If you ever want to experiment with different outputs, get the amp working properly with the original parts then try the subs. http://octopart.com/parts/search?q=IRFB31N20D&js=on __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

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23rd July 2009, 01:48 PM	#2
Dimon74 diyAudio Member Join Date: Feb 2008	Orion amp uses IRFB31N20D not FB21n30.You can use there FQP34N20C or FQP32N20C

23rd July 2009, 01:55 PM	#3
Dimon74 diyAudio Member Join Date: Feb 2008	Replacement for IRF9640 is FQP12P20.You can replace IRFB31N20 with IRF640,but they have almost twice lower current,and higher Rds on resistance.I did that trick in JBL BPX2200.1 which uses same schematic as ORION 2500D but that will decrease capability to drive low ohm loads

23rd July 2009, 06:38 PM	#5
Scanlines diyAudio Member Join Date: Dec 2007	Thanks guys, I will use the originals and I see they ARE available. Sorry about that, I inverted the 2 and 3 when I wrote it down. My apologies.