If it blows the fuse without remote voltage applied, you likely have at least one blown power supply FET.
With your multimeter set to ohms, measure the resistance between legs 1 and 2 of each of the power supply transistors. They should read more than 1000 ohms. If you find that many read much lower and one reads near 0 ohms, you may be able to remove the one that is near 0 ohms to see if there are any other problems.
If you power it up, the transistors should be clamped to the heatsink. It takes only seconds for transistors to fail if there is another problem and they are not clamped down.
Be careful reinstalling the screws. They should go in easily. If they don't, back them out and try to find the original threads. You don't want to cut new threads each time you reinstall them.
With your multimeter set to ohms, measure the resistance between legs 1 and 2 of each of the power supply transistors. They should read more than 1000 ohms. If you find that many read much lower and one reads near 0 ohms, you may be able to remove the one that is near 0 ohms to see if there are any other problems.
If you power it up, the transistors should be clamped to the heatsink. It takes only seconds for transistors to fail if there is another problem and they are not clamped down.
Be careful reinstalling the screws. They should go in easily. If they don't, back them out and try to find the original threads. You don't want to cut new threads each time you reinstall them.
Forgive my ingnorance as I am trying to learn.
I am familiar with the FETs in an electronic speed control for an rc car but I'm not familiar with all the parts in the amp.
I have attached a picture of the power side, if someone can give me some guidance it would be greatly appreciated.
thanks
Dayton
I tried to attach the picture but the file is to big if some can post it for me that would be great.
I am familiar with the FETs in an electronic speed control for an rc car but I'm not familiar with all the parts in the amp.
I have attached a picture of the power side, if someone can give me some guidance it would be greatly appreciated.
thanks
Dayton
I tried to attach the picture but the file is to big if some can post it for me that would be great.
Are you sure that you don't have the power plug on upide down or have the B+ and ground wires reversed?
Check the resistance between legs 2 and 3 of one of the power supply transistors. You only need to check one.
I don't think the output transistors are FETs but I'm not familiar with this amp. Orion has generally used BJTs for the output transistors (for their non-class D amps). Don't try to pry the transistors from the foam tape until you confirm that there is a problem. If there is a problem, there's a better way to break them from the tape.
4 of the devices are likely regulators.
If you got a reading below 10 ohms on the transistors connected to the green resistors, they are defective but there's no way for them to cause excessive current draw without remote voltage applied.
Check the resistance between legs 2 and 3 of one of the power supply transistors. You only need to check one.
I don't think the output transistors are FETs but I'm not familiar with this amp. Orion has generally used BJTs for the output transistors (for their non-class D amps). Don't try to pry the transistors from the foam tape until you confirm that there is a problem. If there is a problem, there's a better way to break them from the tape.
4 of the devices are likely regulators.
If you got a reading below 10 ohms on the transistors connected to the green resistors, they are defective but there's no way for them to cause excessive current draw without remote voltage applied.
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