Re: Infinity 475a car amplifier 75Wx4Ohm
When that pin2 of the SMPS IC is less positive than pin1, that is when the SMPS goes into shutdown. Pin2 can be pulled down toward ground if Q3 is turned on due to error signals from output detection circuits, or if the thermal sensor RT1 resistance goes low to cause pin 2 to be lower than pin 1 which will cause pin3 output to swing HIGH (it is normally LO).
Q7 (2SC1815) symbol is drawn wrong, it is NPN not PNP as shown in the diagram page 28.
You can defeat output detection by lifting D4, but you have to be careful because if there is problem in the output section in one or more of the amplifiers you can have damaged circuits.
When that pin2 of the SMPS IC is less positive than pin1, that is when the SMPS goes into shutdown. Pin2 can be pulled down toward ground if Q3 is turned on due to error signals from output detection circuits, or if the thermal sensor RT1 resistance goes low to cause pin 2 to be lower than pin 1 which will cause pin3 output to swing HIGH (it is normally LO).
Q7 (2SC1815) symbol is drawn wrong, it is NPN not PNP as shown in the diagram page 28.
You can defeat output detection by lifting D4, but you have to be careful because if there is problem in the output section in one or more of the amplifiers you can have damaged circuits.
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