rockford fosgate 100@II

bdgf2004 · 25th October 2010, 10:33 PM

i bought a bad amp and i replaced the p/s fets with irfz44n and one channel with 540/9540. and now the amp works but the repaired channel is distorted. does anybody know what could be causing this? several yrs ago i bought a repair cd from perry babbin and it was very informing. in fact so informing that several yrs later i'm still learning. haha. i've had a fair amount of success, ive repaired bad p/s, outputs, broken boards/traces, ect... but i still have problems with the smaller things (caps, diodes, transistors, ect). if anybody could help it would be great. the pics are of a 60hz wave 1 good 1 bad. i have all te equipment needed and quite a few parts on hand.

bdgf2004 · 25th October 2010, 10:47 PM

the pix. sorry

Perry Babin · 25th October 2010, 10:55 PM

Lift Dx02 and Dx04 in the defective channel. Does that allow it to produce a clean sine wave?

bdgf2004 · 25th October 2010, 11:11 PM

i havent lifted any parts yet but i see that a transistor 2a (q216) that is connected to d204 maybe burnt.

bdgf2004 · 26th October 2010, 09:00 PM

with the diodes out it looks good until it has a load. then it's the same

Perry Babin · 26th October 2010, 10:43 PM

Check Qx12 and Qx13. You need to at least lift two legs so you can check for open junctions and leakage.

bdgf2004 · 27th October 2010, 03:21 AM

both transistors are test good

Perry Babin · 03:42 AM

Did you confirm that the gate resistors and the source resistors are within tolerance?

bdgf2004 · 27th October 2010, 04:00 AM

the big resistor (r263) connected to the source of the 540 is at 700 ohm all others are at 1 ohm. what size is that? i'll have to order some.

Perry Babin · 27th October 2010, 04:07 AM

0.1 ohms, 2w.

While you have it out of the circuit, confirm that R261 and R262 are within tolerance.

25th October 2010, 10:33 PM	#1
bdgf2004 diyAudio Member Join Date: Oct 2010	rockford fosgate 100@II i bought a bad amp and i replaced the p/s fets with irfz44n and one channel with 540/9540. and now the amp works but the repaired channel is distorted. does anybody know what could be causing this? several yrs ago i bought a repair cd from perry babbin and it was very informing. in fact so informing that several yrs later i'm still learning. haha. i've had a fair amount of success, ive repaired bad p/s, outputs, broken boards/traces, ect... but i still have problems with the smaller things (caps, diodes, transistors, ect). if anybody could help it would be great. the pics are of a 60hz wave 1 good 1 bad. i have all te equipment needed and quite a few parts on hand.

25th October 2010, 10:55 PM	#3
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Lift Dx02 and Dx04 in the defective channel. Does that allow it to produce a clean sine wave? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

26th October 2010, 10:43 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Check Qx12 and Qx13. You need to at least lift two legs so you can check for open junctions and leakage. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

27th October 2010, 03:36 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Did you confirm that the gate resistors and the source resistors are within tolerance? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links Last edited by Perry Babin; 27th October 2010 at 03:42 AM.

27th October 2010, 04:07 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	0.1 ohms, 2w. While you have it out of the circuit, confirm that R261 and R262 are within tolerance. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

25th October 2010, 11:11 PM	#4
bdgf2004 diyAudio Member Join Date: Oct 2010	i havent lifted any parts yet but i see that a transistor 2a (q216) that is connected to d204 maybe burnt.

26th October 2010, 09:00 PM	#5
bdgf2004 diyAudio Member Join Date: Oct 2010	with the diodes out it looks good until it has a load. then it's the same

27th October 2010, 03:21 AM	#7
bdgf2004 diyAudio Member Join Date: Oct 2010	both transistors are test good

27th October 2010, 04:00 AM	#9
bdgf2004 diyAudio Member Join Date: Oct 2010	the big resistor (r263) connected to the source of the 540 is at 700 ohm all others are at 1 ohm. what size is that? i'll have to order some.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
rockford fosgate t40001bd	bdgf2004	Class D	5	28th October 2010 06:01 AM
Rockford Fosgate	dtisme	Car Audio	1	5th October 2010 11:39 PM
rockford fosgate p4004	mike49504	Car Audio	3	7th December 2009 09:30 PM
Rockford Fosgate/Mosfet	steven123654	Car Audio	5	2nd September 2009 02:13 AM
rockford fosgate 550x	mike49504	Car Audio	21	6th December 2008 10:26 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read