Re: Help with blowing transistor NAD T752 receiver
Well in the business, you do what you can do with what you have. If the 220Ω resistor is burned, leave it in and assume that stage is bad and keep going upstream to see what else is bad.
Note that the way this is designed, protection doesn't seem to protect the semiconductors, it only protects your speakers and your house from going on fire. Also if one of Q509 and Q510 burns and shorts out, the other one will burn shortly (pun not intended) too. Your audio will sound really distorted when one burns, and will go silent then protection shutdown when the other burns.
Keep comparing with the other channel. Voltages across the transistors between channels should be very similar when given the same input, and yes test with inputs grounded/silence to ensure there's nothing getting hot when quiescent.
Don't worry about overtightening the screw. I think if you have one of those thin handle screwdrivers like a tweaker screwdriver, if you tighten it as much as you can, it is tight enough. You can overtighten if you use one of those "construction" screwdrivers like what they use to screw wood together when building houses - don't use that for transistor heatsinks, only for tightening screw terminals.
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damn... i'm so poor. can't believe i don't have a thermal camera yet...debugging would be so much easier with one of these...
Well in the business, you do what you can do with what you have. If the 220Ω resistor is burned, leave it in and assume that stage is bad and keep going upstream to see what else is bad.
Note that the way this is designed, protection doesn't seem to protect the semiconductors, it only protects your speakers and your house from going on fire. Also if one of Q509 and Q510 burns and shorts out, the other one will burn shortly (pun not intended) too. Your audio will sound really distorted when one burns, and will go silent then protection shutdown when the other burns.
Keep comparing with the other channel. Voltages across the transistors between channels should be very similar when given the same input, and yes test with inputs grounded/silence to ensure there's nothing getting hot when quiescent.
Don't worry about overtightening the screw. I think if you have one of those thin handle screwdrivers like a tweaker screwdriver, if you tighten it as much as you can, it is tight enough. You can overtighten if you use one of those "construction" screwdrivers like what they use to screw wood together when building houses - don't use that for transistor heatsinks, only for tightening screw terminals.
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damn... i'm so poor. can't believe i don't have a thermal camera yet...debugging would be so much easier with one of these...
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