Rockford Fosgate BD500

mike49504 · 17th July 2010, 03:56 AM

This amp is producing positive rail voltage + 73 volts on the IRF540's

On the 9540's i have .004 volts on them.

Wondering what might cause this??

Perry Babin · 17th July 2010, 11:28 AM

What's the DC voltage across legs 1 and 3 of the 9540s?

mike49504 · 17th July 2010, 03:19 PM

Black probe on leg 1 red probe on leg 3: 9.7 volts

Perry Babin · 17th July 2010, 06:05 PM

Is there any DC on the speaker terminals?

If so, what is the voltage (positive/negative is important, black probe on the negative speaker terminal)?

mike49504 · 17th July 2010, 07:28 PM

Black probe on negative speaker terminal Red probe on positive speaker terminal : 0 volts And also checked in millivots still 0

Perry Babin · 17th July 2010, 07:38 PM

Is the amp in protect mode?

mike49504 · 17th July 2010, 08:07 PM

Yes

Perry Babin · 17th July 2010, 08:28 PM

Voltage on U21?

mike49504 · 18th July 2010, 03:52 AM

U21
1:-8.24
2:7.90
3:-8.83
4:-9.67
5:5.00
6:-4.15
7:8.51
8:9.82

Perry Babin · 18th July 2010, 07:43 AM

U21 is very likely defective.

17th July 2010, 03:56 AM	#1
mike49504 diyAudio Member Join Date: Sep 2006	Rockford Fosgate BD500 This amp is producing positive rail voltage + 73 volts on the IRF540's On the 9540's i have .004 volts on them. Wondering what might cause this??

17th July 2010, 11:28 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What's the DC voltage across legs 1 and 3 of the 9540s? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

17th July 2010, 06:05 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Is there any DC on the speaker terminals? If so, what is the voltage (positive/negative is important, black probe on the negative speaker terminal)? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

17th July 2010, 07:38 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Is the amp in protect mode? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

17th July 2010, 08:28 PM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Voltage on U21? __________________ 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 July 2010, 03:19 PM	#3
mike49504 diyAudio Member Join Date: Sep 2006	Black probe on leg 1 red probe on leg 3: 9.7 volts

17th July 2010, 07:28 PM	#5
mike49504 diyAudio Member Join Date: Sep 2006	Black probe on negative speaker terminal Red probe on positive speaker terminal : 0 volts And also checked in millivots still 0

17th July 2010, 08:07 PM	#7
mike49504 diyAudio Member Join Date: Sep 2006	Yes

18th July 2010, 03:52 AM	#9
mike49504 diyAudio Member Join Date: Sep 2006	U21 1:-8.24 2:7.90 3:-8.83 4:-9.67 5:5.00 6:-4.15 7:8.51 8:9.82

18th July 2010, 07:43 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	U21 is very likely defective. __________________ 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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