Rockford Fosgate 1500bd

mike49504 · 17th March 2010, 06:45 AM

Perry,

Dont know what happen to my last Thread cant seem to find it probably overlooked it.

Anyway Ive replaced all of the ic's on the board again. Replaced all of the regulators,resistors for the regulators,all of the outputs, the mic4420's new emitter resistors.

Just finishing up on putting the last 2 ic's back in it.

Wondering is there anything else i should check before i power this up and test the output.

I dont want this thing blowing up for the 5th time

Perry Babin · 17th March 2010, 06:51 AM

Did you check the regulated voltage on the ICs that have been failing?

I hope you're putting the ICs in sockets.

mike49504 · 17th March 2010, 07:13 AM

DO you mean The + - 15 volts? Or what do i check for on the IC'S

Perry Babin · 07:27 AM

Yes. It's ~±10v on this amp (don't expect ±15v). Set your scope to 2mS, 5v/div and DC coupling. touch it to the power supply pins and push on everything in the area to see if the voltage ever varies from the ±10v.

This amp doesn't have any pulldown resistors on the FETs so you should install the opto-coupler before applying power (or desolder the red/black wires on the power supply side of the board <-- this would be best way to prevent damage).

mike49504 · 17th March 2010, 07:35 AM

I can already see this isnt gonna be simple.

I tryed powering it up and it draws 60 amps of current.

I took the mic 4420's out and it still draws excessive current.

Power supply problem?

Perry Babin · 17th March 2010, 07:38 AM

Can you easily desolder all of the outputs? If so, the amp will produce drive signals and you can check them with no chance of damaging the outputs. I know it's going to be somewhat time consuming but it may be worth it.

mike49504 · 17th March 2010, 07:49 AM

Ok i unsolderd the outputs and the amp idles fine

Perry Babin · 17th March 2010, 07:50 AM

Reinstall all of the driver components and op-amps. Do you get a clean square wave on all of the gate pads?

mike49504 · 17th March 2010, 08:08 AM

I will mess with this somemore in the morning i found 2 problems i had 1 output is shorted. And i put U17 in backwards (OPPPSS)

mike49504 · 22nd March 2010, 04:12 AM

Ok what would u iset me scope to ? To check for the square wave on the gates ? All outputs are taken out

17th March 2010, 06:45 AM	#1
mike49504 diyAudio Member Join Date: Sep 2006	Rockford Fosgate 1500bd Perry, Dont know what happen to my last Thread cant seem to find it probably overlooked it. Anyway Ive replaced all of the ic's on the board again. Replaced all of the regulators,resistors for the regulators,all of the outputs, the mic4420's new emitter resistors. Just finishing up on putting the last 2 ic's back in it. Wondering is there anything else i should check before i power this up and test the output. I dont want this thing blowing up for the 5th time

17th March 2010, 06:51 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Did you check the regulated voltage on the ICs that have been failing? I hope you're putting the ICs in sockets. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

17th March 2010, 07:24 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Yes. It's ~±10v on this amp (don't expect ±15v). Set your scope to 2mS, 5v/div and DC coupling. touch it to the power supply pins and push on everything in the area to see if the voltage ever varies from the ±10v. This amp doesn't have any pulldown resistors on the FETs so you should install the opto-coupler before applying power (or desolder the red/black wires on the power supply side of the board <-- this would be best way to prevent damage). __________________ 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; 17th March 2010 at 07:27 AM.

17th March 2010, 07:38 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Can you easily desolder all of the outputs? If so, the amp will produce drive signals and you can check them with no chance of damaging the outputs. I know it's going to be somewhat time consuming but it may be worth it. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

17th March 2010, 07:50 AM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Reinstall all of the driver components and op-amps. Do you get a clean square wave on all of the gate pads? __________________ 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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17th March 2010, 07:13 AM	#3
mike49504 diyAudio Member Join Date: Sep 2006	DO you mean The + - 15 volts? Or what do i check for on the IC'S

17th March 2010, 07:35 AM	#5
mike49504 diyAudio Member Join Date: Sep 2006	I can already see this isnt gonna be simple. I tryed powering it up and it draws 60 amps of current. I took the mic 4420's out and it still draws excessive current. Power supply problem?

17th March 2010, 07:49 AM	#7
mike49504 diyAudio Member Join Date: Sep 2006	Ok i unsolderd the outputs and the amp idles fine

17th March 2010, 08:08 AM	#9
mike49504 diyAudio Member Join Date: Sep 2006	I will mess with this somemore in the morning i found 2 problems i had 1 output is shorted. And i put U17 in backwards (OPPPSS)

22nd March 2010, 04:12 AM	#10
mike49504 diyAudio Member Join Date: Sep 2006	Ok what would u iset me scope to ? To check for the square wave on the gates ? All outputs are taken out

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