Hello
I received a nemesis NA-5KD for repair that had already been operated on previously.
The problem with this amplifier is that the audio output transistors get high temperature in a short time of use, with load and without load.
I have doubts if the driverboard is the original and the audio output inductor coil is the original. Install IRFP260N new 10pc
I did tests with a driverboard P/N 14-2QA0016D-00 and the fault persists
Edit : Also replace all 2T and 2X driver transistors
I received a nemesis NA-5KD for repair that had already been operated on previously.
The problem with this amplifier is that the audio output transistors get high temperature in a short time of use, with load and without load.
I have doubts if the driverboard is the original and the audio output inductor coil is the original. Install IRFP260N new 10pc
I did tests with a driverboard P/N 14-2QA0016D-00 and the fault persists
Edit : Also replace all 2T and 2X driver transistors
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Remove the rectifiers (after discharging the rail caps) and post waveform of drive signal on one high and one low-side FET.
If you have a multimeter that will measure frequency, measure the frequency of that drive signal.
That's a bit high. C706 is responsible for the frequency. The following thread has it at 1nF (1000pF).
https://www.diyaudio.com/community/threads/soundstream-class-d-controller-ic.385770/post-7034976
I don't know if this is the problem but the waveforms look OK, otherwise.
https://www.diyaudio.com/community/threads/soundstream-class-d-controller-ic.385770/post-7034976
I don't know if this is the problem but the waveforms look OK, otherwise.
If that's accurate, wouldn't that be more than 10% out of tolerance.
I'll admit that I don't know if that will make the frequency go up (others will be able to answer this). Capacitance generally has an inverse relationship with frequency but here?
If you have an assortment of capacitors, I'd suggest adjusting the value of the capacitor to get the frequency down to about 120kHz to see if the FETs run cooler and the amp draws less idle current.
I'll admit that I don't know if that will make the frequency go up (others will be able to answer this). Capacitance generally has an inverse relationship with frequency but here?
If you have an assortment of capacitors, I'd suggest adjusting the value of the capacitor to get the frequency down to about 120kHz to see if the FETs run cooler and the amp draws less idle current.