Confirm if the frequency that you are seeing on the heatsink is at the power supply frequency or at the audio section frequency. Perhaps that can point you in a direction of what section in the amp to look at?
I know that you said it was at the audio switching frequency, just confirm it again.
I know that you said it was at the audio switching frequency, just confirm it again.
I'd suggest that you leave the scope connected to the heatsink with everything clamped down. Then start removing clamps, one at a time, and lift the semiconductors to see if the noise decreases for any component.
I don't think this is the main issue but it's hard to say definitively.
We also need to determine why the problem occurs with the head unit but not with your signal generator.
What happens if you jump the RCA shields to the primary ground with a jumper wire?
I don't think this is the main issue but it's hard to say definitively.
We also need to determine why the problem occurs with the head unit but not with your signal generator.
What happens if you jump the RCA shields to the primary ground with a jumper wire?
"If I jump the rca shield ground to primary ground there is no change "
Do you mean that there is still -0.5v and the square wave with the jumper in place?
If you leave the jumper on the RCA shields and plug in the head unit, do you still have the noise?
What if you try your signal generator with the RCA to primary ground jumper? Do you get the noise?
Do you mean that there is still -0.5v and the square wave with the jumper in place?
If you leave the jumper on the RCA shields and plug in the head unit, do you still have the noise?
What if you try your signal generator with the RCA to primary ground jumper? Do you get the noise?
The reason that you probably don't get the noise with the generator is because there is no shield ground.
Do you have a GLI to insert between the head unit and the amp?
If so, remove the jumper and try the head unit with the GLI in place.
Can you use your phone/MP3 player (operating purely from batteries) to see if that has noise?
Do you have a GLI to insert between the head unit and the amp?
If so, remove the jumper and try the head unit with the GLI in place.
Can you use your phone/MP3 player (operating purely from batteries) to see if that has noise?
Not sure what you mean by GLI ?
I have to get a cord for my phone so I can hook up to the amp .
With no rcas plugged into the amp I get the same noise on the speaker terminal .
Wondering if this noise would cause the amp to play then protect then play then protect .
The guy stated that was the problem the amp would protect whenever it wants to it will play fine for a day then the next day it will play and Go into protection over and over .
He never said anything about noise in the system so I’m wondering if the amp doesn’t like something on my test bench and the problem with the noise is on my test bench and not the vehicle
I have to get a cord for my phone so I can hook up to the amp .
With no rcas plugged into the amp I get the same noise on the speaker terminal .
Wondering if this noise would cause the amp to play then protect then play then protect .
The guy stated that was the problem the amp would protect whenever it wants to it will play fine for a day then the next day it will play and Go into protection over and over .
He never said anything about noise in the system so I’m wondering if the amp doesn’t like something on my test bench and the problem with the noise is on my test bench and not the vehicle
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Do you see the 'noise' if you use the secondary ground as the scope ground (connect the small ground wire that connects to the probe hand piece to the secondary ground) and disconnect the wire that connects the scope to the 12v power supply?
I don't think this is causing the hum problem. There is a hum problem as well, correct?
I don't think this is causing the hum problem. There is a hum problem as well, correct?
Still see the noise when I use the secondary center tap as ground reference for the scope
And I talked with the guy today about the amp .
He said the hum is present in the vehicle as well .
He stated the original problem with the amp was the power supply failed he sent the amp in for repair and it came back and the hum was present then
And I talked with the guy today about the amp .
He said the hum is present in the vehicle as well .
He stated the original problem with the amp was the power supply failed he sent the amp in for repair and it came back and the hum was present then
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