nawaz
Junior Member
Posts: 35 
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Post by nawaz on Jan 26, 2014 19:11:32 GMT -5
Performed sequence tune- AND multi on/off, in about 3 seconds of pressing these two buttons, power LED lights up, POWER ON message is displayed on the display board and within 2 seconds blue LED turns off, POWER ON display disappears and MCACC red LED blinks. No amp error or any other error message is displayed or any other LED is on.
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Post by mastertech on Jan 26, 2014 19:27:02 GMT -5
Ok, even with no error display I am sure the problem in on the amp board and this is just how it would act. I would start by testing all the output transistors on the heatsink looking for any shorts between the legs of each. test 1 at a time with your DMM on diode scale looking for a close to short reading.
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 9:54:51 GMT -5
Tested (in-circuit) all the 14 output transistors, none indicated short or single digit resistance value.
I noticed the receiver has 3 overheat sensors connecting the control board at CN1402, CN1403 and CN1404, I disconnected the wire harnesses and turned the system ON, immediately the POWER ON display went dark and Blue LED started blinking. Turning off by pressing power button for 10 or even 20 seconds did not work. Removed the power cord to turn the system OFF. Reconnected the harnesses turned the power on, still the blue LED is blinking, system did not detect that the sensors are reconnected.
Logic tell me that the trouble lies more in the software, when a fault is triggered by any of the sensors, system goes in protection mode and even when the source of trigger is removed system does not reset itself. I wonder if there is a way of resetting the unit.
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Post by mastertech on Jan 27, 2014 10:05:11 GMT -5
Actually that is exactly how it should work. Most, but not all faults must be reset with the tune- and multi on/off button.
Do the reset with those temp sensors hooked up and see if it returns to the blinking MCACC. If it does then reconnect the main transformer harness to the amp board and do the reset again and tell me what it does.
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 11:19:22 GMT -5
Did the reset with temp sensors hooked up, it returned to blinking MCACC red indicator. Reconnected the main transformer harness, connected power cord, reset using tune- AND multi on/off, MCACC indicator went dark, blue power LED lit, POWER ON message displayed on the front display. The unit is exactly in the same state that it was ab-initio. Thanks for bringing back.
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Post by mastertech on Jan 27, 2014 11:45:44 GMT -5
In the beginning, you mean it is all functioning well now?
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 11:50:56 GMT -5
No, I mean when the problem started.
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Post by mastertech on Jan 27, 2014 12:06:16 GMT -5
So back to you plug it in, hear a click, blue light comes on, it says power on and then just the blue light? Wont shut down unless hold button for 10-15 seconds? And MCACC light is not flashing?
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 12:07:44 GMT -5
Yes, exactly so.
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Post by mastertech on Jan 27, 2014 12:21:14 GMT -5
Ok, so now you need to test on the amp board. Again, hopefully stuff is easy to get at. On that connector, CN5701 use pin 4 for your DMM gnd.. Secure it well as it can stay there for testing.
Unit plugged in, DMM on DC voltage look for what I think is a attached board with 4 heavier wires, green, brown, red and blue. Test the red and blue, 1 at a time with your positive probe.
Then locate capacitors, C5708 and C5707. test on + side of C5707 and on neg side of C5708.
give me those reading.
Red wire:_____
Blue wire:_____
C5707:_____
C5708:_____
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 13:30:14 GMT -5
Measurements taken with power cord connected, power LED solid blue, POWER ON message on the display.
Red wire:__53___
Blue wire:__54___
C5707:___Not accessible__
C5708:___Not accessible__
The capacitors C5707 and C5708 are deep inside, I can see them from a very acute angle, but can not measure without removing several boards that are piled up on top of the power board. Power board is at the very bottom. Visual inspection suggests that capacitors are healthy.
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Post by mastertech on Jan 27, 2014 13:36:07 GMT -5
It is not how they look, it is the voltage reading i need. Also, when you are taking a reading I need you to note if the voltage is + or -. Those 2 readings you gave 1 should of been a pos voltage and the other should of been a neg voltage.
i have to run out for a couple hours. When I get back I will check for another location to test those other 2 voltages.
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 14:15:55 GMT -5
My DMM does not indicate the polarity. No matter how I place the meter leads, it only displays the value in numbers with no indication of polarity. I will try to borrow one from my neighbors/friends, if polarity needs to be checked, depending if they have one.
I agree with you regarding capacitor voltage.
I again checked the transistors (for Ohm value, DMM set on diode range) and non is indicating a short, all readings are either in three digits or open.
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Post by mastertech on Jan 27, 2014 15:40:07 GMT -5
Locate connector CN5610 on that amp board. Use pin 4 for gnd.. test pin 1 and then pin 2. Give me those readings. We will try to get around the - factor for now.
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nawaz
Junior Member
Posts: 35
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Post by nawaz on Jan 27, 2014 16:19:39 GMT -5
CN5610 does not seem to be in visual range, what would be its approximate location?
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