Antec SL350P worth fixing?

[Th3_uN1Qu3]

I've gotten a number of power supplies yesterday, including this one. I was impressed by the amount of caps and inductors they could cram on the secondary and by the full transient filter, however the caps are a huge letdown (all Fuhjyyu), especially the 330uF primary caps. They all look fine but i'll test them on the ESR meter that i built 2 days ago just to make sure.

Anyway, this thing is basically shot to hell. The board is burned in the primary, interestingly not under any transistor. The "fuse" (which someone replaced with a piece of wire) did not blow, the primary switchers test fine, but the standby switcher is toasted. The wire used for a fuse was thin enough, i also have a couple others with intact fuse but blown standby circuit, they all blew up in the same way. It does nothing when i plug it in, which i think is kinda weird for a shorted transistor (no fireworks? ), but the others with blown standby switch do the same.

So is this thing worth fixing? I don't really like running stuff with burned PCBs, but this one looks decent otherwise. Alternatively, i think i could "upgrade" three L&C PSUs with what's in this one. I'll post a pic tonight.

[momaka]

Re: Antec SL350P worth fixing?

They are decent power supplies, minus the 5vsb circuit. At least from what I understood when reading a few of Everell's threads on 2-transistor 5vsb circuits is that they are hard to troubleshoot/repair. This is why he normally does his infamous DM311 chip mod. Here's a few similar Antec PSUs he modified:
https://www.badcaps.net/forum/showthread.php?t=8403

The "fuse" (which someone replaced with a piece of wire) did not blow

And this is strange, how?

[Th3_uN1Qu3]

Re: Antec SL350P worth fixing?

They are decent power supplies, minus the 5vsb circuit.

Okay, then it's disassembly time.

And this is strange, how?

I use wire like that, actually a bit thicker, when i'm out of fuses. And it blows at 5A. If the wire would have been thick enough, in the event of a catastrophic failure one of the primary capacitors would have blown open, which it didn't.

[goodpsusearch]

Re: Antec SL350P worth fixing?

My experience with antec:
https://www.badcaps.net/forum/showthread.php?t=8385

If you want fireworks you can try replacing a 4.7ohm resistor that is used as a "fuse" of sorts in 5vsb circuit. I replaced it and plugged one of my antecs and...BANG

[momaka]

Re: Antec SL350P worth fixing?

Well, the L&C PSUs also have a 2-transistor 5vsb circuit (for some reason, though, they do seem to last longer than the Antecs). Just make sure to replace the critical 5vsb cap on those (usually a 22uF or 47uF on the primary side).

I use wire like that, actually a bit thicker, when i'm out of fuses.

I've had a bad experience with that before, that's why I'm a bit paranoid when I see someone use a wire in place of a fuse . But if it works for you, then good. You can also just wire a 100W lightbulb in series instead of a fuse - if a short occurs, the light bulb will turn on.

[Th3_uN1Qu3]

Re: Antec SL350P worth fixing?

Well, the bulb prevents large scale destruction when testing, but otherwise it just gets in the way, because it drops a lot of voltage.

Anyway, while taking the caps out i noticed why it wasn't working - the bridge rectifier was missing. But at the state that the board was in, i wasn't keen to put the caps back in and install a bridge.

Btw, *all* the Fuhjjyu caps inside tested good.

[seanc]

Re: Antec SL350P worth fixing?

Funny side note, I got hold of an Antec Smartpower earlier in the week.
All Fuhjjyu caps *look* ok, but a teapo and the OST primaries are bulged.

This particular PSU is manufactured "backwards". Antec designed it that way for their 3U rackmount case. Input power, exhaust fan (I hope it is reversed in this unit) and cables all come out of one side, the side that would usually face outwards.

[Quasar]

Re: Antec SL350P worth fixing?

Well, the bulb prevents large scale destruction when testing, but otherwise it just gets in the way, because it drops a lot of voltage.

Use a higher wattage bulb. I use a 60 or 100 to start with then switch up to a 200 if I see the item is not shorted. Some stuff just won't fire with a 100.

Btw, *all* the Fuhjjyu caps inside tested good.

Quick, frame them.

[stj]

Re: Antec SL350P worth fixing?

if you write one off, i need a PFC coil.

[everell]

Re: Antec SL350P worth fixing?

if you write one off, i need a PFC coil.

You didn't wind a replacement coil? Is a replacement coil all you lack in doing the repair?

[stj]

Re: Antec SL350P worth fixing?

no, it needs a coil, a recap and a pfc fet.
(and maybe the pfc chip - dont know yet)
i can buy most of it, but i didnt rewind the coil because of warnings here about heat effecting the core.

[Th3_uN1Qu3]

Re: Antec SL350P worth fixing?

Well get yourself that inductor calculation software off Micrometals' site, and it'll tell you what you need to do to it so it doesn't get hot.

[stj]

Re: Antec SL350P worth fixing?

it got hot because the fet shorted and put it across the supply rails!!!!

[Th3_uN1Qu3]

Re: Antec SL350P worth fixing?

Then it only happened for a short period of time right? There's no need to worry in that case.

[stj]

Re: Antec SL350P worth fixing?

um no, it got so hot that it stripped the laquer off the windings and put tiny surface cracks in the core!

i found a core the same size in something else - not a psu.
it may be good for a rebuild but i'm not sure if there is more to cores than dimensions.

[goodpsusearch]

Re: Antec SL350P worth fixing?

um no, it got so hot that it stripped the laquer off the windings and put tiny surface cracks in the core!

i found a core the same size in something else - not a psu.
it may be good for a rebuild but i'm not sure if there is more to cores than dimensions.

I don't get why the fuse of the psu or the house short switch did not go down.

[stj]

Re: Antec SL350P worth fixing?

because the internal resistance of the fet (about 7ohms) was enough to let it cook without blowing the fuse for a while!

[everell]

Re: Antec SL350P worth fixing?

um no, it got so hot that it stripped the laquer off the windings and put tiny surface cracks in the core!

That means the coil got super hot. It caused the coating on the coil wire to get brittle and crack. The coil then shorted, which caused the FET to short.

If nothing else is available, take the output toroid transformer off a junked power supply. Remove all of the windings. If core is same size, wind a new coil on that core. Perhaps not best, but I have done it and it does work.

[stj]

Re: Antec SL350P worth fixing?

or keep the modular case and bin the rest!

tbh i only kept it because it had modular cabling, a recap & rebuilding the pfc area is gonna cost a third the cost of a new 400w corsair!

[stj]

Re: Antec SL350P worth fixing?

my notes about it!
---------------------------

antec sp-500p psu

irfp460a
>1653669 farnell 4.42p


.1/50 [ec27]
.22/50 [r98! "-" toward heatsink]
.33/50 [ec17]
1/50 [ec14,15,16] (x3)
2.2/400 [ec28]
4.7/50 [ec3,4] (x2)
10/16 [fan-pcb]
10/50 [1c1,ex13,26] (x3)
22/16 [fan-pcb] (x3)
22/50 [ec5]
47/50 [ec6,12] (x2)
220/16 6.5mm [ec16]
330/16 6.5mm [ec20]
470/200 22mm (x2)
1000/10 8mm [ec10,11] (x2)
1000/10 10mm [above R96]
2200/10 10mm [between 5v & gnd]
3300/16 10mm [ec19]
4700/6.3 10mm [ec24,25]

---------------------------