Hi all. I'm hoping someone can help shed some light on an issue I have with one of my active Behringer Truth B2031 studio monitors.
These monitors use 3 x LM3886 amp ics. One 3886 for the high frequencies & two in parallel for the mids/low frequencies.
As the title of this thread says, one of the monitors overheat, it gets extremely hot, then starts "ticking" as the thermal protection kicks in & out.
Even when it is sitting idle, it overheats. I have read up on this & it "seems" to be related to the input dc offset.
Unfortunately, I'm not too sure exactly how & where to test this dc offset voltage. What I have done so far is: I removed one of the LM3886 ic's.
Then the speaker works nicely & doesn't heat up at all, but it's obviously not as loud as the other one. I have measured all the resistors related to the output of both ic's & they all measure perfect according to the schematic. I've measured for any dc on the outputs - none. I've tried to measure dc voltage on the input pins of the ic (thinking this is where I would find the offset voltage) - none. Impedance of the driver measures at 6.3 ohms.
I have attached the schematic diagram in the hopes that someone with more knowledge can take a look & possibly point me in the right direction here.
Any help will be appreciated. Thanks in advance.
These monitors use 3 x LM3886 amp ics. One 3886 for the high frequencies & two in parallel for the mids/low frequencies.
As the title of this thread says, one of the monitors overheat, it gets extremely hot, then starts "ticking" as the thermal protection kicks in & out.
Even when it is sitting idle, it overheats. I have read up on this & it "seems" to be related to the input dc offset.
Unfortunately, I'm not too sure exactly how & where to test this dc offset voltage. What I have done so far is: I removed one of the LM3886 ic's.
Then the speaker works nicely & doesn't heat up at all, but it's obviously not as loud as the other one. I have measured all the resistors related to the output of both ic's & they all measure perfect according to the schematic. I've measured for any dc on the outputs - none. I've tried to measure dc voltage on the input pins of the ic (thinking this is where I would find the offset voltage) - none. Impedance of the driver measures at 6.3 ohms.
I have attached the schematic diagram in the hopes that someone with more knowledge can take a look & possibly point me in the right direction here.
Any help will be appreciated. Thanks in advance.
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