problems with fosgate p2002 amp

arazs5 · 14th April 2010, 01:41 AM

when remote power is applied to my amp the fuse blows out...i was just successful (thanks to the help of many on this forum) repairing a kenwood amp with bad output transistors which had the same fuse blowing problem...could anyone tell me how to identify the output transistors??? the previous fixed amp had a blowout on one...this fosgate amp doesn't have any obvious "blow outs"...which are they outputs, or where should i start with this one?!?!?!?!?!?

Perry Babin · 14th April 2010, 01:45 AM

The output transistors are the large transistors on the heatsink with their third leg connected to the large resistors.

Brain Fried · 14th April 2010, 01:57 AM

Here a new mother board for your P2002 24.95 with free shipping.
NEW Rockford Fosgate P200.2 Punch AMP - eBay (item 390173894657 end time Apr-22-10 07:52:50 PDT)

arazs5 · 14th April 2010, 02:16 AM

so the transistors on the left side and the top left? thanks also for the ebay link...might be my best bet, but i want to possibly try to learn something

Perry Babin · 14th April 2010, 02:18 AM

The two boards 'may' be (are likely) identical in function but the P2002 has a segmented LED display that is driven by an audio signal. The electronics for the display are in the cover but the supply voltage and audio signal may not be used/supplied in the P200.2 board. If you get the two schematic diagrams from Rockford, you could compare them to see if the signals on the ribbon cable are the same.

If they are the same, the board would likely be cheaper than the parts and shipping. This assumes that the board is not a factory reject due to a manufacturing defect.

arazs5 · 14th April 2010, 02:33 AM

so perry, sorry to be so annoying, but by looking at the picture could you tell, do you know, which transistors are the outputs? will they always be connected to the "big" resistors??

Perry Babin · 14th April 2010, 02:47 AM

In general, class AB and class B amplifiers will have the emitter or source terminals of their audio output transistors connected to large, low value resistors. There are exceptions but this is extremely common in class AB/B amps.

brandes.cm · 14th April 2010, 04:09 AM

That board uses the 28n15 and 36p15 fets. Fairchild semi has the 28n15 for $2, but out of the 36P15. Arrow electronics show stock of both on the 13th of april.

These parts can be a little tricky soldering back on the MESHA strip!!!

The P4004 schematic is here, just two extra channels: Projects (brandescm)

DREW028 · 18th May 2012, 03:50 AM

I'm getting straight dc to the right channel and distortion on the left. Did I need a torch to desolder these transistors?

Perry Babin · 18th May 2012, 05:52 AM

Start a new thread.

14th April 2010, 01:45 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The output transistors are the large transistors on the heatsink with their third leg connected to the large resistors. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

14th April 2010, 02:18 AM	#5
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The two boards 'may' be (are likely) identical in function but the P2002 has a segmented LED display that is driven by an audio signal. The electronics for the display are in the cover but the supply voltage and audio signal may not be used/supplied in the P200.2 board. If you get the two schematic diagrams from Rockford, you could compare them to see if the signals on the ribbon cable are the same. If they are the same, the board would likely be cheaper than the parts and shipping. This assumes that the board is not a factory reject due to a manufacturing defect. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

18th May 2012, 05:52 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Start a new thread. __________________ 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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14th April 2010, 01:57 AM	#3
Brain Fried diyAudio Member Join Date: Apr 2010	Here a new mother board for your P2002 24.95 with free shipping. NEW Rockford Fosgate P200.2 Punch AMP - eBay (item 390173894657 end time Apr-22-10 07:52:50 PDT)

14th April 2010, 02:16 AM	#4
arazs5 diyAudio Member Join Date: Mar 2010 Location: northwest indiana	so the transistors on the left side and the top left? thanks also for the ebay link...might be my best bet, but i want to possibly try to learn something

14th April 2010, 02:33 AM	#6
arazs5 diyAudio Member Join Date: Mar 2010 Location: northwest indiana	so perry, sorry to be so annoying, but by looking at the picture could you tell, do you know, which transistors are the outputs? will they always be connected to the "big" resistors??

14th April 2010, 04:09 AM	#8
brandes.cm diyAudio Member Join Date: Sep 2009 Location: Wisconsin	That board uses the 28n15 and 36p15 fets. Fairchild semi has the 28n15 for $2, but out of the 36P15. Arrow electronics show stock of both on the 13th of april. These parts can be a little tricky soldering back on the MESHA strip!!! The P4004 schematic is here, just two extra channels: Projects (brandescm)

18th May 2012, 03:50 AM	#9
DREW028 diyAudio Member Join Date: Jun 2004 Location: chicago	I'm getting straight dc to the right channel and distortion on the left. Did I need a torch to desolder these transistors?

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