JBL BP600.1 Car amplifier

argonrepublic · 10th August 2009, 07:07 AM

Checked out a car amp. Not blowing fuses but is blowing inline fuse. I opened it up and found at least one bad transistor.
I am a novice but am expecting to find rectifier issues.
The blown IC is a Fairchild K0138. I could not match those numbers. The next set of numbers is FQP50N06. That comes up as a fet. Would that also be rectifier? or is that an out put?a few pairs of leads from toroidial go to these fairchilds. That is what I found at a glance. Am going to se the amp tomorrow.
Thanks!

Perry Babin · 10th August 2009, 07:40 AM

What's the circuit board designation (IC..., Q...) for the blown IC?

If it only blows the fuse after remote voltage is applied, it likely has a problem in the audio section (likely shorted output transistors). The rectifiers rarely fail. They should be marked ESC25M02D. Their circuit board designation should be D761 and D762.

The FQP50N06s are the power supply FETs. If it blows the fuse with only B+ and ground connected, they may be defective.

Did you find any shorted output transistors (IRF540, IRF9540)?

argonrepublic · 10th August 2009, 01:31 PM

Should I replace all or only defective FETs?

Perry Babin · 10th August 2009, 01:33 PM

It depends on which ones are defective.

argonrepublic · 11th August 2009, 02:19 AM

Ok Guess I will pull them and check them all. Someone offered to sell me IRFZ48s to replace the Fairchilds. Suggested that they would be more durable.

Perry Babin · 11th August 2009, 02:33 AM

The blown part is an FQP65N06? If so, then you must replace Q742-744 and Q752-754. You amps need to check all of the 22 ohm gate resistors, Q741 and Q751.

After removing the 6 power supply FETs, power up the amp and measure the DC voltage on the solder pad for each of the power supply FETs.

Did you check the output transistors? If not, you need to do so before ordering any parts.

10th August 2009, 07:07 AM	#1
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	JBL BP600.1 Car amplifier Checked out a car amp. Not blowing fuses but is blowing inline fuse. I opened it up and found at least one bad transistor. I am a novice but am expecting to find rectifier issues. The blown IC is a Fairchild K0138. I could not match those numbers. The next set of numbers is FQP50N06. That comes up as a fet. Would that also be rectifier? or is that an out put?a few pairs of leads from toroidial go to these fairchilds. That is what I found at a glance. Am going to se the amp tomorrow. Thanks!

10th August 2009, 07:40 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What's the circuit board designation (IC..., Q...) for the blown IC? If it only blows the fuse after remote voltage is applied, it likely has a problem in the audio section (likely shorted output transistors). The rectifiers rarely fail. They should be marked ESC25M02D. Their circuit board designation should be D761 and D762. The FQP50N06s are the power supply FETs. If it blows the fuse with only B+ and ground connected, they may be defective. Did you find any shorted output transistors (IRF540, IRF9540)? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

10th August 2009, 01:33 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It depends on which ones are defective. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

11th August 2009, 02:19 AM	#5
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	JBL amp Ok Guess I will pull them and check them all. Someone offered to sell me IRFZ48s to replace the Fairchilds. Suggested that they would be more durable.

11th August 2009, 02:33 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The blown part is an FQP65N06? If so, then you must replace Q742-744 and Q752-754. You amps need to check all of the 22 ohm gate resistors, Q741 and Q751. After removing the 6 power supply FETs, power up the amp and measure the DC voltage on the solder pad for each of the power supply FETs. Did you check the output transistors? If not, you need to do so before ordering any parts. __________________ 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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10th August 2009, 01:31 PM	#3
argonrepublic diyAudio Member Join Date: Apr 2005 Location: Simcoe Ont	Should I replace all or only defective FETs?

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