How can I test ICE2QR4765 without an oscilloscope

[abdolah]

Hi everyone hope you having a fantastic day
I wanna to ask if I can test this IC (ICE2QR4765) , it's an smps pwm controller , to make sure that it's fully working without an oscilloscope, I have my multimeter with frequency meagrment , and I have my power supply 15v 1A ,

[Harry_22]

Hi! You can measure p-n diode  structure from CS to Drain for breakdown.
And also the supply current in normal operation should be around 1.5 mA. I am not shure regarding ZC pin but CS in this case must be connected to ground.
But why do you need to test the controller separately?

[DavidAlfa]

If you're replacing it and have fear that the new one is fake or bad and might blow everything up, connect it with a 100-500W resistive load in series with the mains input (I.E. a light bulb or a heater) so it limits the current, avoiding a destructive short.
Plus the light bulb will provide visual feedback if there's a short.

If you're troubleshootign a non-working device, the internal mosfet is very unlikey to go bad without catastrophic consequences, 99% of the time it'll blow up the entire thing.
If the fuse isn't blowing up on, start by measuring voltage in FB and VCC pins.
But remember it's mains voltage, so be safe!

The circuit in these is quite simple, so it should be pretty easy to trace the issue.
A shorted rectifier or diode, broken resistor, bad optocoupler...
If the old one blew up, the current sense resistors (Connected to CS pin) usually go bad too, so check them.

[abdolah]

Sorry for the late response, I was having a hard time 😞
My PSU is trying to start but it stops for some reason I have changed all caps with good ones replaced p223 supervisor IC replaced the 5v and 3.3v ic MOSFET controller

[abdolah]

Yes I'm repairing my PSU, and the issue is quite complicated
First the PSU was not starting then I checked some components and found a 10ohm resistor that was open and I replaced it the the power supply work on it self when I pluge the mains without the pson signal , then I thought it's a supervisor IC problem then I replaced it and now it's powering on for half a second then power off , the I replaced the 5v and 3.3v controller and the same
problem