Antec SP500P "resurrection"

[Khron]

Re: Antec SP500P "resurrection"

Will do, as soon as i get back home, in a couple of hours. "Top down" = photo from the component & heatsink side, right?

Time zone difference <= i'm currently studying and working in Finland; currently 1:34pm over here

The 5vsb board is only done "virtually"; i'll enlarge the drain trace anyway, for better heat dissipation. I'll figure out something until i actually etch it / put it together.

[everell]

Re: Antec SP500P "resurrection"

Also, before etching that pc board, you might want to add a little more heat sink. See my attached photo as suggestion.

[Khron]

Re: Antec SP500P "resurrection"

Yeah, something like that is what i meant by "enlarging the drain trace"

[Khron]

Re: Antec SP500P "resurrection"

Ok, here are the results of today's photo shoot: two views of the solder-side (so each side can be well seen in the foreground), one view from the top, and a detail with the PFC section.

[everell]

Re: Antec SP500P "resurrection"

Solder side photos look great. Now you might as well remove the other heat sink and its transistors The smaller of the three transistors is the 5vsb switcher which you won't be using. So you will have to remove the heat sink to get it out. Then you can take some photos of the entire top side of the board and we can begin looking for other damage around the switchers. You won't be able to see it very well until that heat sink is out of the way.

While you have the heat sink out you will be able to measure the transistors for leakage. Also let us know what transistors are being used (markings on the transistors). Mine were D209, yours may be something else.

[Khron]

Re: Antec SP500P "resurrection"

Yeah, i was thinking about removing the other heatsking as well. Gonna do that when i get back home today (leaving for school / work pretty soon; 7:30am here).

Expect updates in about 8-9 hours from now.

[stj]

Re: Antec SP500P "resurrection"

that's the pfc coil that's desroyed on mine.

[Khron]

Re: Antec SP500P "resurrection"

Update: As i was de-soldering the main switchers, i got to the 5vsb switcher, and i noticed there's an exfoliated track (the one that passes under the J6 chip jumper, and maybe under the (MELF) ZD4 (there's some black stuff between it and the board surface).

This is somewhat visible in the 3rd photo from my initial post.

[Khron]

Re: Antec SP500P "resurrection"

I ended up bringing the PSU and my soldering gun to school, so here's a couple more photos, the primary heatsink with the silicon, and a "more naked" top view of the board.

[Khron]

Re: Antec SP500P "resurrection"

The main switchers (2SC3320) seem ok (Vbc=436-438mV, Vbe=527-540mV). PFC diode = 392mV, PFC switcher seems ok (483mV with red probe on drain and black probe on source).

[everell]

Re: Antec SP500P "resurrection"

Resistors in main switching circuit don't look burnt - that's a good sign.

The value of the burnt resistor (see attached photo) is 22 ohms 5%. I think you will need to replace it!

[Khron]

Re: Antec SP500P "resurrection"

A "sanity check" question: if i remove the blown resistor that goes to the PFC's Vcc (upper right of the standby trafo), it SHOULD stay off, and the coil and diode in series on the V+ shouldn't hurt anything, right?

Speaking of which, i don't suppose anyone has a value for that, right? Oh, and then there's the well-cooked zener (i assume), between the two small caps, next to the green NTC...

Just thought i'd make sure and try to "cover all the bases" before starting any sort of testing...

[stj]

Re: Antec SP500P "resurrection"

i can give you value / part number for anything - i have one in bits myself.

[Khron]

Re: Antec SP500P "resurrection"

That's great The only "anonymous" parts are the ones i mentioned in my previous post. Apart from those, and the resistor that everell mentioned and the PWM, everything else looks ok.

[everell]

Re: Antec SP500P "resurrection"

The bad transistor which caused the burn damage needs to be replaced. See circled parts in attached photo. The diode in the circle is probably bad also. You will not be able to measure it while in circuit. It is just a 4148 diode, very common.

[everell]

Re: Antec SP500P "resurrection"

Remove this transistor from heat sink. The new 5vsb IC will replace this. Just put it in your hope chest (hope you get to use it some day!)

[Khron]

Re: Antec SP500P "resurrection"

That small bad driver transistor is an H945 device. I looked up the datasheet for that, and the 2SC1815 and they seem to be a 95% match (a difference in the ft, but for switching at under 200KHz, that shouldn't be so critical). I've got a few of those recovered from some other psu's so i'll make the switcharoo tonight.

Still wondering about the values of those other two burnt parts i mentioned earlier, though

[everell]

Re: Antec SP500P "resurrection"

Did you measure the H945 transistor after removing it from the pc board? I am curious as to what you find.

If you change the H945 transistor to a 1815 from another psu board, change BOTH H945 transistor drivers - they are a push pull driver and should be somewhat matched. Using two 1815 transistors off the same board should match close enough - but one H945 and one 1815 MIGHT cause some problem.

Not sure about the zener. Looks like protection for VCC on the pfc chip. My guess is something on the order of 18 to 20 volt zener should work. Perhaps someone else could be more specific. Since the zener is fried, the capacitor next to it might also be bad. Since you are recapping all caps, guess that problem is already solved!

[Khron]

Re: Antec SP500P "resurrection"

I wasn't even considering a "half-arsed" job regarding part replacement. And i'm quite a fan of symmetry anyway, so of course i'll shove in two 2SC1815's. And "of course", that Teapo (with the pattern on top) next to the fried zener is bulged. Haven't seen such small caps bulge too often, though

The PFC chip datasheet says max Vcc's 21V, so i'll see if i can get my hands on an 18-20V zener somewhere at school.

Thanks for all the assistance this far, and i'll keep you posted with any progress i'll make these days

[Khron]

Re: Antec SP500P "resurrection"

I just measured the (first) extracted H945, the one where the burnt trace leads to, and it shows open-circuit all the way, no matter which way i connected the test leads (both diode test and the 200ohm range on the DMM).