the gutless, bloated, and fried power supply hall of shame

[Behemot]

Re: the gutless, bloated, and fried power supply hall of shame

I think it's some extra winding, maybe for -12 or some feedback, the ground will be on central pin most likely.

[Heihachi_73]

Re: the gutless, bloated, and fried power supply hall of shame

That text is standard on every Thermal Master.

[kc8adu]

Re: the gutless, bloated, and fried power supply hall of shame

also on hipro.

That text is standard on every Thermal Master.

[momaka]

Re: the gutless, bloated, and fried power supply hall of shame

also on hipro.

I have never seen a HiPro PSU with Engrish like that.

[senz_90]

Re: the gutless, bloated, and fried power supply hall of shame

This thing came in a case. CWT, you should be ashamed! This thing is so bad. No input filtering, 330uF input caps (They're actually 220uF) 13007's, one of the smallest main transformers I've seen in an ATX PSU, 16A for 3.3V and 5V. 10A for 12V. hardly any filtering, tiny output coils. Look at the grounding wire for the transformer This thing is just horrible.

this is the winner's exactly !! LOL !! imagine that !!! that transformer as small as coin !! i've never looks like that PSU transformer..

[PeteS in CA]

Re: the gutless, bloated, and fried power supply hall of shame

Please double-check tell me this really is NOT the grounding wire! If it is, it would be absolutely ridiculous. Maybe a bad joke on CWT's part?

...

A wire that thin won't carry ground current (unless you need a nightlight). Maybe it's the ground wire for a Faraday shield in the transformer that either broke loose or was left unconnected?

[mariushm]

Re: the gutless, bloated, and fried power supply hall of shame

I agree, it's not ground wire, can't be. Just flip the pcb and see where the negative of the output capacitors is connected to... that's the ground pin of the transformer.

I'm going with a feedback coil or maybe the output of a thermal sensor built into the transformer.

[momaka]

Re: the gutless, bloated, and fried power supply hall of shame

A wire that thin won't carry ground current (unless you need a nightlight). Maybe it's the ground wire for a Faraday shield in the transformer that either broke loose or was left unconnected?

I know, but with these gutless PSUs, you never know who was working the late Friday night shift .

[SIDMX]

Re: the gutless, bloated, and fried power supply hall of shame

FSP F350-A went seppuku!

Took motherboard, processor and 1GB DDR2 with it, primary transistors were MJE13009, there are several resistors burned around the area and mexico just put a new satellite into orbit (a small OST cap)

Customer said he pushed power button and heard a pop then smoke came out of computer, any guesses here about the "sequence of selfdestruction"? This is my first F350-A so I need your advice as if it is worth the time to try a repair.

[shadow]

Re: the gutless, bloated, and fried power supply hall of shame

Fair bit of damage! I haven't built a system for years now. However I thought FSP built good power supplies and just require a recap.

[ben7]

Re: the gutless, bloated, and fried power supply hall of shame

Probably was a random failure, maybe the switching transistors shorted out and backfed into the capacitor, which is in the driving circuit for the switching transistors.

[PeteS in CA]

Re: the gutless, bloated, and fried power supply hall of shame

Concur with ben7. The damage seen in the pictures you posted is in the inverter circuit - the switch transistors and the base drive components. What I find interesting is that the damage to the P/S is on the primary side, but that catastrophe seems to have propagated through the output transformer, creating a voltage surge large enough to wipe out the motherboard. Maybe the fan seized up and let the switch transistors cook themselves?

Based on the 0621 datecode (21st week of 2006) on that one OST input cap I'm going to guess that this power supply is about 7 years old, not exactly new or old. A decent design in a reasonable operating environment should last longer. About the design generally, a 350W rating seems optimistic. Based on the heatsinks, 250W seems more realistic (if not a bit optimistic). Based on the output inductor core material and use of transistors for the switch devices, it probably operated between 20KHz and 50KHz. Two switch transistors suggest a half-bridge design, voltage-mode control and a TL494 ("real" or clone) PWM. I may be wrong, but I don't see the large film capacitor on the primary side that is often used with half-bridge designs to prevent the main transformer core from "walking" in to saturation, due to small imbalances between the two switch devices. Assuming the fan did not seize up, it could be that the 13009s were not well matched (or aged differently), the output transformer core saturated, and the 13009s went .

[momaka]

Re: the gutless, bloated, and fried power supply hall of shame

This is my first F350-A so I need your advice as if it is worth the time to try a repair.

It's a simple half-bridge design, so it should be fairly easy to fix once you find all of the components that went bad (and there will be quite a few on the primary side). There's also the 5VSB circuit - it's a 2-transistor design. If I was to fix this power supply, I'd do something about the 5VSB circuit as well before it goes into a computer.

I may be wrong, but I don't see the large film capacitor on the primary side that is often used with half-bridge designs to prevent the main transformer core from "walking" in to saturation, due to small imbalances between the two switch devices.

I think it's on the far side near the front grille. Probably a smaller one and harder to see on that picture.

[SIDMX]

Re: the gutless, bloated, and fried power supply hall of shame

Thanks for the input guys, I just finished testing hard drive and optical drive and to my surprise both are toasted so this PSU took the entire computer with it.

...What I find interesting is that the damage to the P/S is on the primary side, but that catastrophe seems to have propagated through the output transformer, creating a voltage surge large enough to wipe out the motherboard. Maybe the fan seized up and let the switch transistors cook themselves?

Fan and fan speed circuit works as it should, don't know what could have happened but the magnitude of damage is what really surprise me, I've seen even crappy units like low end Key Mouse with shorted 13007s and none of them damaged the entire system.

... Two switch transistors suggest a half-bridge design, voltage-mode control and a TL494 ("real" or clone) PWM. I may be wrong, but I don't see the large film capacitor on the primary side that is often used with half-bridge designs to prevent the main transformer core from "walking" in to saturation, due to small imbalances between the two switch devices...

It uses propietary chip but i guess it is a functional equivalent to a 494 +339 maybe ? About the film cap it does have one rated at 2.2uf 1KV btw thanks for the info i didn't know what was the purpose of that big film cap.

It's a simple half-bridge design, so it should be fairly easy to fix once you find all of the components that went bad (and there will be quite a few on the primary side). There's also the 5VSB circuit - it's a 2-transistor design. If I was to fix this power supply, I'd do something about the 5VSB circuit as well before it goes into a computer.

Turns out this PS does not use 2-transistor circuit for SB, it uses an KA1H0165R from Fairchild's Power Switch Series so at least this is one thing less to fix.

I will try to fix it but after seeing the disaster caused by this unit I don't know if it will be smart to use it again inside a computer.

[Behemot]

Re: the gutless, bloated, and fried power supply hall of shame

All FSP Groups PSUs I had in my hands so far did their rated power without problems. FSP tried to minimize heatsinks for very long time, I bet there are multiple secondary rectifiers in paralel and the whole heatsink is transfering heat to metal casing, fastened with screw.

They were also somewhat ahead before the other mainstream products as they implemented protections amongst the first manufacturers. Probably the long secondary IC monitors overvoltage, undervoltage and maybe also some other values as well (possibly some limited OCP).

These days they are sinking down, their gold Fortron Aurum does not even have functional OPP. Probably has OCP (weren't able to bring it to action though), but while loading all rails of 500W model, voltage drops below 10,8 V at +12 V and than sooner or later UVP kicks in. Not really a high-end to me…Be Quiet! E9 is the same inside, just with some fancy stuff and higher price.

[Pentium4]

Re: the gutless, bloated, and fried power supply hall of shame

All FSP Groups PSUs I had in my hands so far did their rated power without problems.

True. Although the ripple on some of them was a little high, especially the older ones. I wonder if this is from the extra heat from having inadequate heatsinks.

[Pentium4]

Re: the gutless, bloated, and fried power supply hall of shame

Can't get that Thermal Master to blow up. I ran it at 215W for 7 hours, the secondary heatsink only got up to 70C, because that fan is a howler. Thing is, I don't have more "power hungry" equipment that I don't care about in case the thing decides to kill attached hardware when it blows! Surprised that transformer can handle that much load

[ben7]

Re: the gutless, bloated, and fried power supply hall of shame

Can't get that Thermal Master to blow up. I ran it at 215W for 7 hours, the secondary heatsink only got up to 70C, because that fan is a howler. Thing is, I don't have more "power hungry" equipment that I don't care about in case the thing decides to kill attached hardware when it blows! Surprised that transformer can handle that much load

What was the temp of the primary side heatsink? Bridge rectifier?

If you want it to explode, try removing the fan and see what happens xD

[Pentium4]

Re: the gutless, bloated, and fried power supply hall of shame

I'm going to try taping half of the exhaust The primary heatsink only got to 62C, the diodes were ~35C cause they are right next to the leaf blower fan. The fan really is that loud....

[Jooo]

Re: the gutless, bloated, and fried power supply hall of shame

Chinese 1$ including shipping phone charger.
Brand is TJ Courier Charger, specs 5v 500ma.

Surprisingly, this thing works.