Hi, how are you? I am working on this amplifier, it turns on normal and works at low volume, but as the volume increases it goes into protection and marks short. I have checked that the fault enters through pin 10 of the lm339d and I was given the task of reviewing the protection circuit and it turned out that in the right channel I activate the fault and it is protected, I already checked the protection circuit and it is well , in the diode that feeds towards the lm339d the voltage increases from 0 to 10 v when the fault is activated I ask for help to see if they can guide me to find what causes this it should be mentioned that I already check the fqa36p15 and fqa28n15 and they are fine that more could it be? attached a photo of the diagram with which I am leaning greetings
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Hi Mjimenez
Is the threshold of activation the same if one channel has a minimal load -- say 100 ohms or more?
Can you provide a little more of the schematic? Some of these machines have pretty complicated, far-reaching tentacles -- with that much power they have to be careful not to start fires. 😉
Regards
Is the threshold of activation the same if one channel has a minimal load -- say 100 ohms or more?
Can you provide a little more of the schematic? Some of these machines have pretty complicated, far-reaching tentacles -- with that much power they have to be careful not to start fires. 😉
Regards
Have you monitored the output terminals with a meter to see if any DC voltage appears before the protect trips?
When you stated that the protection circuit was OK, what did you check?
Did you confirm that the low-value resistors connected to the source resistors were all within tolerance?
Did you confirm that all of the source resistors were within tolerance?
Did you confirm that the low-value resistors connected to the source resistors were all within tolerance?
Did you confirm that all of the source resistors were within tolerance?
Hi Rick PA Stadel, Seankane and Mr Perry Babin .... Rick PA Stadel doesn't know what you mean by the activation threshold, how do I measure it? And if at one time I upload more of the schematic I am using. Seankane if I have monitored it and I have no DC at the output even when the protection trips. Mr. Perry Babin, the low value resistors connected to the source resistors are fine and the source resistors are also fine ... in the attached photo is where the increase in the voltage is given I will mark it through a transistor Q2003 (2L) and it reaches the diode D2000 from here it connects to the LM339D a voltage of 10 to 12v comes out when the volume increased and if it decreased the Protection disappears and everything about the schematic i checked
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Is it possible that the protection circuit has a reason to be engaging and the problem is actually in the audio circuit?
I changed the resistors to 22 ohms, but still the same is protected in the matter of the audio circuit that what should I check? If I already check the mosfets, what else could that cause me?