Greetings colleagues this Chinese amplifier, I reach my hands without audio, the power LED does not turn on just like the LEDs of the equalizer potentiometers but if the front panel illuminates and the fan is activated, curiously 2 of the LEDs of the inputs Microphones are turned on, which in normal operation does not occur. thinking that maybe it could be the bad outputs first disassemble 2 of the transistors of a channel and turned on the plant and then the other 2 to see if the panel lights were normalized but I had no results, Checking the card I found a transistor Short B649A that is connected to the 6800 microfarad line filters for 50 volts and in turn to a connector that carries voltages to the front control board where all the potentiometers of volume, tone, microphones, etc., are located. This plant uses 4 FS18SM transistors and here is my doubt because when measuring them the 4 give me the same reading, it marks me as if I had a diode between pins 2 and 3 and in the rest of the combination of pins alternating the tips of the multimeter does not mark anything, look the FS18SM datasheet and it tells me that it is a mosfet N channel, my question for colleagues is how to measure this component accurately and if they could be good according to the reading that explains them ... Could this sun fail or due to an absence of voltage towards the faceplate caused by the damage of the B649A? Thank you in advance for your suggestions, greetings from Venezuela