JL Audio 500/1 repair info

Bertje · 17th October 2009, 04:22 PM

Hello,
I have here a JL Audio 500/1 d class monoblock. Power supply failed, I changed all mosfets (FPQ65N06) and gate-resistors (47 ohm).
Worked, but has very low railvoltage, maximum undistorted output is 15w, then it clips.
I think the drivers of the mosfets from the PS are also faulty, I measure a pulses of about 5v and 1,7uS from the SG3525 (OK) but after the drivers they are distorted.

Drivers are UY 142 and WY 143
I looked at smd coding tabels etc. but can't find them....which type I can use here??

Thanks,
Rob.

Perry Babin · 17th October 2009, 09:18 PM

jl 500/1 SMD transistors

Bertje · 17th October 2009, 10:17 PM

Thanks a lot! Sorry for not searching.....
Rob.

Bertje · 27th October 2009, 09:14 PM

OK, power supply is OK now, up to 150v dc at the rectifier out without a load.
Is this a regulated supply?
Rob.

Perry Babin · 27th October 2009, 09:32 PM

You shouldn't have more than ~80v at the rectifier.

Yes, it's regulated.

Bertje · 09:34 AM

OK thanks. I measure 150v DC with the rectifier disconnected from the rest of the PS. Just AC input, no load.
So I think something's wrong with the feedback of the regulation. Also a resistor was burnt 6k2 (R661) which I changed for 6k8, difficult to see what this resistor do without schematic. Could be in the PS regulation loop, not sure.
Rob.

Perry Babin · 28th October 2009, 09:49 AM

What is the voltage on the first two pins of the driver board (looking at the component side of the driver board)?

I think you'll have to have the rectifier installed but I'm not sure.

Are you 100% sure that you read 160v DC on the center leg of the rectifier? It should have caused the filter caps to vent at 2x their rated voltage.

Bertje · 28th October 2009, 11:06 AM

I connected only the outside legs of the rectifier to the board. The center leg is not connected, floating. Then I measure 150V dc. No regulation offcourse.

With the rectifier connected (normal regulation) the output is about 40Vdc.
Or the PS regulation is defect, or the amplifier is..

But with signal on, I have normal amplifier output to 15w, then it's clipping.

So I suspect the regulation of the powersupply.

Strange problem...
Rob.

Perry Babin · 28th October 2009, 05:59 PM

What is the voltage on the first two pins of the driver board (looking at the component side of the driver board)?

Bertje · 28th October 2009, 07:56 PM

I got your cd and info, so when I looked at the pinvoltages:
1 = 9,2V feedback ? (
2 = 2,5V Ref
and the rest are OK.
The resistor in front of the feedback was burnt and is exchanged for 6k8 (was 6k2). This resistor is connected directly to pin 1.
Close...
Rob.

17th October 2009, 04:22 PM	#1
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	JL Audio 500/1 repair info Hello, I have here a JL Audio 500/1 d class monoblock. Power supply failed, I changed all mosfets (FPQ65N06) and gate-resistors (47 ohm). Worked, but has very low railvoltage, maximum undistorted output is 15w, then it clips. I think the drivers of the mosfets from the PS are also faulty, I measure a pulses of about 5v and 1,7uS from the SG3525 (OK) but after the drivers they are distorted. Drivers are UY 142 and WY 143 I looked at smd coding tabels etc. but can't find them....which type I can use here?? Thanks, Rob.

17th October 2009, 09:18 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	jl 500/1 SMD transistors __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

27th October 2009, 09:32 PM	#5
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	You shouldn't have more than ~80v at the rectifier. Yes, it's regulated. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

28th October 2009, 09:30 AM	#6
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	OK thanks. I measure 150v DC with the rectifier disconnected from the rest of the PS. Just AC input, no load. So I think something's wrong with the feedback of the regulation. Also a resistor was burnt 6k2 (R661) which I changed for 6k8, difficult to see what this resistor do without schematic. Could be in the PS regulation loop, not sure. Rob. Last edited by Bertje; 28th October 2009 at 09:34 AM.

28th October 2009, 09:49 AM	#7
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What is the voltage on the first two pins of the driver board (looking at the component side of the driver board)? I think you'll have to have the rectifier installed but I'm not sure. Are you 100% sure that you read 160v DC on the center leg of the rectifier? It should have caused the filter caps to vent at 2x their rated voltage. __________________ 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 October 2009, 10:17 PM	#3
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	Thanks a lot! Sorry for not searching..... Rob.

27th October 2009, 09:14 PM	#4
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	OK, power supply is OK now, up to 150v dc at the rectifier out without a load. Is this a regulated supply? Rob.

28th October 2009, 11:06 AM	#8
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	I connected only the outside legs of the rectifier to the board. The center leg is not connected, floating. Then I measure 150V dc. No regulation offcourse. With the rectifier connected (normal regulation) the output is about 40Vdc. Or the PS regulation is defect, or the amplifier is.. But with signal on, I have normal amplifier output to 15w, then it's clipping. So I suspect the regulation of the powersupply. Strange problem... Rob.

28th October 2009, 05:59 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What is the voltage on the first two pins of the driver board (looking at the component side of the driver board)? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

28th October 2009, 07:56 PM	#10
Bertje diyAudio Member Join Date: Jan 2004 Location: Holland	I got your cd and info, so when I looked at the pinvoltages: 1 = 9,2V feedback ? ( 2 = 2,5V Ref and the rest are OK. The resistor in front of the feedback was burnt and is exchanged for 6k8 (was 6k2). This resistor is connected directly to pin 1. Close... Rob.

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