Hi guys
I got this power supply that is damaged. No history behind it. Power supply has two separate inputs, 110V and 230V, could be that somebody connected it to the wrong input.
Upon opening i could see that Q11 5N80 is blown, and also MX6 UC3843 blown. On further checking diodes CR11 and CR12 (both U1D) are shorted, also diode CR19 BYV26E. Also the fuse from the DC line that is coming to this part of power supply.
Unfortunately when i was taking out the white glue from PCB i damaged diode CR46. Well i am not sure which one is it. It's connected between VCC and GND on UC3843. I installed there 1N4148, hopefully that's ok?
I have disconnected primary part of the power supply that it seems that is working properly without rest of circuits, It's giving out 332V and 166V between GND and 2 positive DC lines.
This 332V is going to the second part of the circuit, and among the other things is going through the 150k resistor to the VCC for UC3843. I am getting 8V after that resistor.
After all those parts are replaced and when i connect it to mains (230V) the FET 5N80 starts to heat a lot, so i have to unplug mains immediately.
Output of power supply tested by regulated power supply, connected 24V and current draw was around 40mA.
So i assume something around this PWM circuit is not working properly, but have no idea what, FET not driven properly? What it could be?
I got this power supply that is damaged. No history behind it. Power supply has two separate inputs, 110V and 230V, could be that somebody connected it to the wrong input.
Upon opening i could see that Q11 5N80 is blown, and also MX6 UC3843 blown. On further checking diodes CR11 and CR12 (both U1D) are shorted, also diode CR19 BYV26E. Also the fuse from the DC line that is coming to this part of power supply.
Unfortunately when i was taking out the white glue from PCB i damaged diode CR46. Well i am not sure which one is it. It's connected between VCC and GND on UC3843. I installed there 1N4148, hopefully that's ok?
I have disconnected primary part of the power supply that it seems that is working properly without rest of circuits, It's giving out 332V and 166V between GND and 2 positive DC lines.
This 332V is going to the second part of the circuit, and among the other things is going through the 150k resistor to the VCC for UC3843. I am getting 8V after that resistor.
After all those parts are replaced and when i connect it to mains (230V) the FET 5N80 starts to heat a lot, so i have to unplug mains immediately.
Output of power supply tested by regulated power supply, connected 24V and current draw was around 40mA.
So i assume something around this PWM circuit is not working properly, but have no idea what, FET not driven properly? What it could be?
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