The output stage of your amp is a TDA8920 single chip Class D amplifer. It has thermal and over current protection. Driving the equivalent of a short circuit should not cause it to fail. Consider yourself lucky.
Here is what the datasheet says:
"8.3.2 SHORT-CIRCUIT ACROSS THE LOUDSPEAKER
TERMINALS AND TO SUPPLY LINES
When the loudspeaker terminals are short-circuited or if
one of the demodulated outputs of the amplifier is
short-circuited to one of the supply lines this will be
detected by the current protection. If the output current
exceeds the maximum output current of 7.5 A, then the
power stage will shut down within less than 1 ms and the
high current will be switched off. In this state the
dissipation is very low. Every 100 ms the system tries to
restart again. If there is still a short-circuit across the
loudspeaker load or to one of the supply lines, the system
is switched off again as soon as the maximum current is
exceeded. The average dissipation will be low because of
this low duty cycle."
Here is what the datasheet says:
"8.3.2 SHORT-CIRCUIT ACROSS THE LOUDSPEAKER
TERMINALS AND TO SUPPLY LINES
When the loudspeaker terminals are short-circuited or if
one of the demodulated outputs of the amplifier is
short-circuited to one of the supply lines this will be
detected by the current protection. If the output current
exceeds the maximum output current of 7.5 A, then the
power stage will shut down within less than 1 ms and the
high current will be switched off. In this state the
dissipation is very low. Every 100 ms the system tries to
restart again. If there is still a short-circuit across the
loudspeaker load or to one of the supply lines, the system
is switched off again as soon as the maximum current is
exceeded. The average dissipation will be low because of
this low duty cycle."
Check fuses first, they might have caught it in time.
If not its probably blown output transistors.
Only way to check is to buzz them out with a multi-meter.
Sometimes drivers break when outputs go too.
I did the same trick many years ago and got lots of smoke !
If not its probably blown output transistors.
Only way to check is to buzz them out with a multi-meter.
Sometimes drivers break when outputs go too.
I did the same trick many years ago and got lots of smoke !