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I explained it in the video.
After replacing the switcher, I forgot to short the boot pin then I realized it and then I shorted the boot pin and it worked.
Another strange thing is that the 12V was missing for some time then it got present.
Anyway I will put this PSU in a rig and check if it...
No missing voltage. It's working perfectly.
One good thing that helped me is having another working identical PSU to compre it for measurements.
I have other faulty ones but different models. Now if I can't repair them easily then I better find a working one which will help a lot.
I didn't know what you mean by dry points, maybe you mean bad soldered points that are loose or cracked out. But the soldered point on this PCB are ok.
Yep that what I do all the time no way I would connect any PSU that is targeted for repair without the protection lamp.
Yep, you're right...
Strange thing, which is the faulty PSU is now working and all the voltages are present. Maybe the -12V is -11.36V I don't know if it's a problem or not.
But there's something affecting the stability of this PSU and cause it to shutdown, and then it could boot up without problems.
Hi,
Latest updates, well, in regard to the main issue I declared in the thread title. Which is there's no voltage on the source pin, and actually that's how the circuit should work because the drain could be connected to the auxiliary transformer.
One of these PSUs is working with now...
Good morning,
I tested the caps with the capacitance meter, there are only 2 electrolytic caps on the line side. They measure the exact as rated value.
Luckily, I found a working PSU with the exact model number and PCB. Now I hope to do some comparative measurements and find the issue and...
Hi,
Today I'm checking without powering up the PSU, I want to find the problem using the ohmmeter, continuity or diode meter.
My main suspect now is that it could be either the main MOSFETs or the optocouplers.
First let me investigate the optocouplers if the measurements I'm getting are ok...
Yep, I know this concept as the line side carries +320V, and I'm very careful with using the DMM probes. I know that any mistake will cause a short between a two lines with different potentials.
As I encountered a incident happened to me, where I forgot to move the screwdriver a way + I wasn't...
Even if I'm using a current limiter lamp ? I just received this 100W/220V heat lamp, and it's working.
I tested a working PSU and the lamp didn't interrupt the launch of the PSU. But didn't encounter a short circuit one until now, but hopefully it will glow when there's a short in the PSU.
Hi,
I did a quick check today and found that there are components shorted to the GND.
1. All the MOSFETs in the yellow boxes have the gate and source shorted to ground, but the drain isn't.
2. The MOSFET in the blue box isn't shorted.
3. The switcher source is also shorted to ground.
What...
I'm sorry I forgot to mention that I have some PNY280pn chips, so I replaced it with a new one but the same result.
And this is the way I was checking the voltages on this chip, putting the red probe on the chip pins and the black on the -ve of the capacitor.
1710286757
This what I'm thinking...
Hi,
I started working on this Dell PSU after purchasing a new 220V/100W current limiter lamp.
My start inspection is that the PNY280pn has 385V on Drain pin but 0V on source side. Why it's not working ?
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