The reason it's shut down is because of the input to pins 1 or 2. Can you post good quality photos (in focus, no flare from the flash...) of the top and bottom of the board around the 494?
These boards likely suffer from bad connections. Any place that there is solder both on top of and bottom of any component lead, bad connections can occur.
These boards likely suffer from bad connections. Any place that there is solder both on top of and bottom of any component lead, bad connections can occur.
The solder connections on the FETs look like there could be shorts. Make absolutely sure that there are none before doing anything else.
There is a transistor near pin 8 of the 494. It appears that it's directly connected to pin 2 of the 494. If so, remove it and clean up the solder connections.
This may completely disable the protection circuit. If the amp draws excessive current when powering up, be prepared to quickly disconnect it.
Does the amp power up without that transistor in the circuit?
There is a transistor near pin 8 of the 494. It appears that it's directly connected to pin 2 of the 494. If so, remove it and clean up the solder connections.
This may completely disable the protection circuit. If the amp draws excessive current when powering up, be prepared to quickly disconnect it.
Does the amp power up without that transistor in the circuit?
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