Soundstream Rubicon 502 Repair Problem

Blazemore · 8th January 2010, 08:39 PM

Been trying to figure out whats wrong with a Rubicon 502 board. The board will not power up, none of the leds will light up, no output. The board doesn't have any burnt marks other than some blackish around the bottoms rectifiers(?). Tested each outer legs to:
330k
467k

Any ideas on where to look. Please describe ideas, still in the learning curve.

Pics of the board and attached the schematic.

Perry Babin · 8th January 2010, 09:12 PM

Clamp the transistors tightly to the heatsink and insert a 10 amp fuse in the B+ line.

Power the amp up and post the voltage on all 16 pins of the SG3524.

SG3524
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:

1moreamp · 9th January 2010, 05:09 PM

Here is a little more detailed info on your troubles, just trying to be helpful...

Q68 is a MPSW51A and it supplies the 12 volts to the LM3524 PWM control chip.

Q69 is a MPS8099 and it is the turn on transistor for the amp, thus it gets the 12 turn on through this transistor to the PWM supply.

TS1 and TS2 are temperature switches and they can inhibit turn on if they are dysfunctional...

This info plus what Perry has asked for should get you started on your quest...

Blazemore · 12th January 2010, 12:33 AM

NP any help is welcome.

I didn't have much luck in tracing the out the pins. If I'm right then..

Pin 1: 0.00
Pin 2: 2.74
Pin 6: 3.24
Pin 7: 2.21
Pin 10: 0.00
Pin 14: 0.00
Pin 16: 4.92

I did measure each pin with the amp facing in front of you, top pins from left to right:
4.92, 11.35, 0.00, 11.35, 11.35, 0.00, 0.02, 0.18

Bottom pins from left to right:
.002, 2.74, 0.28, 0.00, 0.00, 3.24, 2.22, 0.00

Perry Babin · 12th January 2010, 01:37 AM

Pin 9 needs to go higher for the IC to produce output. From the input voltages, it appears that something external is pulling it down. Remove and check D18. C57 may be leaking (electrically) which could pull it down.

With D18 out if the circuit, all transistors clamped tightly to the heatsink and a 10 amp fuse in the B+ line, power up the amp. Does it produce rail voltage with D18 out of the circuit?

Blazemore · 14th January 2010, 06:13 PM

Pulled D18 and the amp did power up, good sight to see. I checked points TP8 and TP9 with 20.04 / -20.04vdc.

Tested D18 with open and 228v.

Blazemore · 15th January 2010, 04:11 PM

Perry you think maybe replacing C57 and see?

Blazemore · 27th January 2010, 06:11 PM

Replaced C57 and D18 but still will not power up. Took D18 back out and the amp powers up. All three leds stay on red and TP10 and TP11 are showing 16.45.
Any other idea's?

Perry Babin · 27th January 2010, 08:13 PM

What's the DC voltage on the 3 legs of Q38?

Blazemore · 29th January 2010, 01:10 PM

The center leg is .013 and two outer legs are .000.

8th January 2010, 09:12 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Clamp the transistors tightly to the heatsink and insert a 10 amp fuse in the B+ line. Power the amp up and post the voltage on all 16 pins of the SG3524. SG3524 Pin 1: Pin 2: Pin 3: Pin 4: Pin 5: Pin 6: Pin 7: Pin 8: Pin 9: Pin 10: Pin 11: Pin 12: Pin 13: Pin 14: Pin 15: Pin 16: __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

12th January 2010, 01:37 AM	#5
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Pin 9 needs to go higher for the IC to produce output. From the input voltages, it appears that something external is pulling it down. Remove and check D18. C57 may be leaking (electrically) which could pull it down. With D18 out if the circuit, all transistors clamped tightly to the heatsink and a 10 amp fuse in the B+ line, power up the amp. Does it produce rail voltage with D18 out of the circuit? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

27th January 2010, 08:13 PM	#9
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What's the DC voltage on the 3 legs of Q38? __________________ 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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9th January 2010, 05:09 PM	#3
1moreamp diyAudio Member Join Date: Dec 2005 Location: Northern California	Here is a little more detailed info on your troubles, just trying to be helpful... Q68 is a MPSW51A and it supplies the 12 volts to the LM3524 PWM control chip. Q69 is a MPS8099 and it is the turn on transistor for the amp, thus it gets the 12 turn on through this transistor to the PWM supply. TS1 and TS2 are temperature switches and they can inhibit turn on if they are dysfunctional... This info plus what Perry has asked for should get you started on your quest...

12th January 2010, 12:33 AM	#4
Blazemore diyAudio Member Join Date: Jan 2010 Location: NC	NP any help is welcome. I didn't have much luck in tracing the out the pins. If I'm right then.. Pin 1: 0.00 Pin 2: 2.74 Pin 6: 3.24 Pin 7: 2.21 Pin 10: 0.00 Pin 14: 0.00 Pin 16: 4.92 I did measure each pin with the amp facing in front of you, top pins from left to right: 4.92, 11.35, 0.00, 11.35, 11.35, 0.00, 0.02, 0.18 Bottom pins from left to right: .002, 2.74, 0.28, 0.00, 0.00, 3.24, 2.22, 0.00

14th January 2010, 06:13 PM	#6
Blazemore diyAudio Member Join Date: Jan 2010 Location: NC	Pulled D18 and the amp did power up, good sight to see. I checked points TP8 and TP9 with 20.04 / -20.04vdc. Tested D18 with open and 228v.

15th January 2010, 04:11 PM	#7
Blazemore diyAudio Member Join Date: Jan 2010 Location: NC	Perry you think maybe replacing C57 and see?

27th January 2010, 06:11 PM	#8
Blazemore diyAudio Member Join Date: Jan 2010 Location: NC	Replaced C57 and D18 but still will not power up. Took D18 back out and the amp powers up. All three leds stay on red and TP10 and TP11 are showing 16.45. Any other idea's?

29th January 2010, 01:10 PM	#10
Blazemore diyAudio Member Join Date: Jan 2010 Location: NC	The center leg is .013 and two outer legs are .000.

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