My pc100 does not start

[Drack]

Re: My pc100 does not start

Found a shorted diode

[Drack]

Re: My pc100 does not start

.I can put 240, I have 240 on my room actually but I'm to lazy to put a power outlet for 4% better efficiency, thanks Pete,capleaker,a24, sam, and everyone that helped me. Btw what it's newer half bridge or this?

[PeteS in CA]

Re: My pc100 does not start

What A24 said. It's a universal input flyback design. No doubler, and no need to divide the rectified primary voltage (as would be necessary for a half bridge design). Were you in EuroLand the voltage across that cap would be on the order of 340V. Using one 400V cap instead of two 200V caps in series saves PCB space.

[Drack]

Re: My pc100 does not start

It doesn't have PFC, the PSU say it can handle 100v/240v, it's weird, I would check everything I can today, and I will let you know if I see something weird

[CapLeaker]

Re: My pc100 does not start

I looked it's glue, what I don't understand is why is just 160v on the main caps that is a 400v, shouldn't be 370ish

120V AC x 1.414 = 170V DC on the main rectifier with the unit off. Since it has a PFC, it will boost the voltage on the main filter cap to like 370V DC when turned on. If the PSU is turned on and you don't have boosted voltage on the main filter cap, then there is something wrong with the PFC IC, or the PSU doesn't get the PSon signal, etc.

[Agent24]

Re: My pc100 does not start

Because your line voltage is only 110VAC and that PSU has no voltage doubler or Active PFC boost circuitry. After rectification, you get a higher voltage in DC. You can calculate it by multiplying the AC voltage by 1.414 to get the DC voltage. eg: 110 x 1.141 = 155 (about 160).
It could be that your line voltage is a bit higher than 110v, maybe 113v.


The 400V written on the capacitor just means it can handle up to 400V without blowing up.


It makes me wonder though. Is this PSU actually designed for 110V supply? Running SMPS at lower line voltages than they are supposed to run on can be stressful and cause damage.

[Drack]

Re: My pc100 does not start

I looked it's glue, what I don't understand is why is just 160v on the main caps that is a 400v, shouldn't be 370ish

[Agent24]

Re: My pc100 does not start

Well that 8-pin chip on the primary side certainly looks as if it has some damage on the top. Or maybe it's just glue\paint. I can't tell, the photo isn't clear enough.

[Drack]

Re: My pc100 does not start

It doesn't have a hole, the transistor is fine, most be the pwm, the mov was behind a coil, I already took it out

[CapLeaker]

Re: My pc100 does not start

I can't tell on that pic if it has a hole or not, but I am sure as heck that the PWM is dead for one reason or the other. Either it isn't getting any Vcc or it's dead.

[sam_sam_sam]

Re: My pc100 does not start

That 8-Pin PWM controller does look like it has a hole in it.

It sure does look like that IC-chip has a hole in it
It needs to be replaced

[Agent24]

Re: My pc100 does not start

Fuse might have blown because of a bad MOV, or maybe the MOV blew from a voltage spike and blew the fuse. A spike may have damaged something else too.
But not sure where the MOV is you speak of, I only see two Y-Capacitors and neither looks bad.

Switching transistor might have shorted but then burned out and gone open-circuit afterwards. There doesn't need to be a heck of a lot (if any) outward signs of this on the component body either (although there usually is)

That 8-Pin PWM controller does look like it has a hole in it.

[Drack]

Re: My pc100 does not start

¡Happy new year guys!

[Drack]

Re: My pc100 does not start

I already have another PSU lol, and 25 bucks is what you won on 3 months over here on average I will check tomorrow its almost 23:00 over here, thanks for the help

[CapLeaker]

Re: My pc100 does not start

anyway... see if the PWM gets proper Vcc voltage on pin 7. If not, it may either be in under voltage lockout, or the dropping resistor feeding it went high in value. Other than that, you can try changing it out, or buy for 25 bux another one from flea-bay.

[Drack]

Re: My pc100 does not start

It has its 8 pins(weird) this PSU is at 25 bucks on eBay lol

[CapLeaker]

Re: My pc100 does not start

maybe a UC3842? See if the PWM has proper Vcc (pin 7)

[Drack]

Re: My pc100 does not start

It says uc3142p

[Drack]

Re: My pc100 does not start

Pete, when I took the rectifier out the resistance went up to 3200ohm I think

[CapLeaker]

Re: My pc100 does not start

that's a voltage comperator, not a PWM. I am looking for the smaller IC with 8 legs next to the large main filter cap.