Hi Guys
Working on a HD 8000. Amp came with a blown power supply. Customer did inform me that he given amp to another tech to repair and it played for about 5secs or less and then amp went up in smoke. On opening the unit i found that the other tech used 65n06 instead of IRF1404. I also found all the 10R resistors to be open. I replaced all the FETS(all from the same batch) and the all the 10R as well as the 4x IR4427 chips.
Powered unit and only to find that all 3 LEDS light up. The blue LED is brighter that the others as shown in the picture below:
SO next I checked to see if I was to see if the IR chip was getting power, which it is on pin 6. I also checked to see if I was getting wave form from the pic to the IR 4427 but nothing coming into the chip. I traced back to find that wave form comes from Pin 5 and 6 of the PIC controller. No matter how slow I turn down my scope i get nothing from from pin 5 and 6.Here are the pics of pin 5 and 6:
I am getting my 5 volts to power the PIC.
Any ideas if there is something else that is causing the problem or is it just the PIC that is gone faulty.
Here are some pics of the board:
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Working on a HD 8000. Amp came with a blown power supply. Customer did inform me that he given amp to another tech to repair and it played for about 5secs or less and then amp went up in smoke. On opening the unit i found that the other tech used 65n06 instead of IRF1404. I also found all the 10R resistors to be open. I replaced all the FETS(all from the same batch) and the all the 10R as well as the 4x IR4427 chips.
Powered unit and only to find that all 3 LEDS light up. The blue LED is brighter that the others as shown in the picture below:
SO next I checked to see if I was to see if the IR chip was getting power, which it is on pin 6. I also checked to see if I was getting wave form from the pic to the IR 4427 but nothing coming into the chip. I traced back to find that wave form comes from Pin 5 and 6 of the PIC controller. No matter how slow I turn down my scope i get nothing from from pin 5 and 6.Here are the pics of pin 5 and 6:
I am getting my 5 volts to power the PIC.
Any ideas if there is something else that is causing the problem or is it just the PIC that is gone faulty.
Here are some pics of the board:
[/ATTACH]
Attachments
DO you have 12V at pins 6 of the 4427? If not, check the two large smd resistors R150 and R135 in front of the white 5W array, and D19
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Yes i am getting 12v on Pin 6 of 4427. I did manage to get hold of the the guys from Taramps (very helpful). They did go through the amp with me and we found that it is the PIC. Pin 1 of the PIC get 5v but you need PIN 4 to also have 5v on it. this 5v on pin 4 is not there so the guys have told me that it is the PIC.
they did offer me another PIC to buy from them. About 5 USD. the only problem is delivery charges are to expensive works out to about 60USD and when I convert to my country exchange (ZAR) cost of part is just to expensive for client to want to have the unit repaired.
Please don't post in a repair thread that was started by someone else unless you are trying to help them.
Start a new thread if you need help with a repair of your own.
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Start a new thread if you need help with a repair of your own.
http://www.bcae1.com/temp/newthreaddiy01.png