Yes. I didn't fully checked the transistors pin numbers, but with beep mode this seemed excactly the same. Diodes and resistors all correct in place.
One difference, 1302 on the photo is a 1303 (placed near the driver board)
And is connected to SD pin2 as shown on the photo.
One difference, 1302 on the photo is a 1303 (placed near the driver board)
And is connected to SD pin2 as shown on the photo.
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Do you have an LED? Any LED will work.
If so, remove D52.
The LED and a series 1k current limiting resistor will connect between the collector of Q52 and the 12v regulator output of the 12v regulator that powers the 21844s.
Does the LED light for a couple of seconds on startup and momentarily when the amp powers down?
If so, remove D52.
The LED and a series 1k current limiting resistor will connect between the collector of Q52 and the 12v regulator output of the 12v regulator that powers the 21844s.
Does the LED light for a couple of seconds on startup and momentarily when the amp powers down?
I assume if I remove the 15v rail to standard rails the output fets still die, yes. There has nothing changed on the driver board yet, and it blew twice with the bad driver board.
The fets already blow up with startup with standard rail voltage.
The board emptied the rail caps with the bad driver board.
With good driver board the caps were still charged.
2 problems with the bad driver board:
It blows while startup (PWM is not delayed until full rail is reached)
It empties rail caps while powering off
The fets already blow up with startup with standard rail voltage.
The board emptied the rail caps with the bad driver board.
With good driver board the caps were still charged.
2 problems with the bad driver board:
It blows while startup (PWM is not delayed until full rail is reached)
It empties rail caps while powering off
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The 12v supply generally has 100uf caps on the input and output of the 12v regulator (referenced o the negative rail). I'd try increasing them to 1000uf (if that type of circuit is what you have).
There is likely a way to do something with mute/delay circuit using a jfet but that would require a few more components to make it work. The increase in capacitance would be much easier.
There is likely a way to do something with mute/delay circuit using a jfet but that would require a few more components to make it work. The increase in capacitance would be much easier.
I fitted 1000uf caps in the input and output of the voltage regulators, 4 in total.
This does not have great effect on the output fet switching delay.
It waits about 100ms longer, but not until full rail voltage is reached.
Also the rail voltage is still dumped while powering off.
This does not have great effect on the output fet switching delay.
It waits about 100ms longer, but not until full rail voltage is reached.
Also the rail voltage is still dumped while powering off.
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