APF PSUs and HEAT

[bigbeark]

I have had 3 PSU's - supposed to be high-quality with APF - that I have removed from three different PC's - because they blow hot air and seem to run hot.

The three in question are Antec 450 (Antec Sonata case), Seasonic 430, and
Zippy Emacs HP2-6460P. The Antec and Seasonic were purchased new and have almost no time on them. They have not been used in an overclock or under-ventilated situation.

Should I not be concerned about the hot air? If I use for example a Dynex 400 watt PSU, there are no hot air issues at all.

[c_hegge]

Re: APF PSUs and HEAT

Are the fans on these PSUs temperature controlled? If so, then it may just be that the fams don't spin fast until it gets really hot.

What series is the antec? If it's a smartpower, then beware. They are full of fuhjyyu caps. They also run hot. It takes a lot of heat for the back fan to kick in.

[370forlife]

Re: APF PSUs and HEAT

It depends on how much you are loading on them. If the Zippy, seasonic, and Antec are not ramping up the fans too high then they may get a little hot. Either that or they are moving more air through them so you are feeling a higher volume of hot air.

The Dynex isn't too cool either though. Hardwaresecrets test of it had almost 60C dumping through the back with 48C intake temps (about the temp of the inside of a computer)

[stj]

Re: APF PSUs and HEAT

better out than in.
speedup the fans.

[everell]

Re: APF PSUs and HEAT

Using more fan power to blow the hot air out does not get to the root cause of the problem. Where is the extra heat coming from??? If extra heat is coming from power supplies with APFC, then we may be looking at a new problem area which needs to be seriously addressed.

I have recently repaired a HP DPS-340CB A which had a blown APFC board. One of the APFC MOSFET transistors was shorted. A film capacitor was ruptured and damaged. Two coils wired in series (used as APFC coil) were both fried. And fuse blown. If FET shorts, fuse blows, and psu goes dead. So WHY were these coils burned so badly? Look carefully at the photos of the two coils and you can see that the heat damage of these two coils is different. One was much hotter than the other. With that much heat damage, I was not sure if the torroid cores would be affected or not, so I wound two new coils on different cores. Power supply now works, but those two new coils get hot. Just run the power supply about an hour, turn off power supply and wait a minute for caps to discharge, then touch the coils (quickly). They are very HOT.

I would think that a HOT APFC coil would indicate lots of current draw in the APFC transistors. Perhaps the main capacitor (270 uF/400 volts) is not handling the ripple currents from APFC which run at about 67 khz??? I have repaired some other psu with APFC problems and had bulging, leaking main capacitor.

[stj]

Re: APF PSUs and HEAT

i have also had a bad apfc with incinerated coil and shorted fet, the rating on the fet is massive!

am i right in thinking the circuit is creating a pulsed load?
if so, does this not increase the power consumption for the user?

maybe we should be removing these circuits instead of fixing them.

[370forlife]

Re: APF PSUs and HEAT

What APFC does it makes the apparent power and actual power the same. It basically brings down the apparent power.

It dosen't cost the end user any more, just makes it cheaper for the power companies as they don't have to pay for the apparent power (lets say 400W) while the consumer pays for the actual power (300W assuming a PF of .75)

[everell]

Re: APF PSUs and HEAT

am i right in thinking the circuit is creating a pulsed load?

All of the APFC circuits I have seen use a pwm type chip driving a pair of FETs in parallel. The coil is the load for the FETs. This pulsing signal is added to the existing DC voltage, thus giving you a pulsing DC voltage running at a frequency of 67khz to 100 khz. The main capacitor - usually about 270 uF/400 volts is filtering this pulsing signal.

[stj]

Re: APF PSUs and HEAT

antec smart-power uses a single fet driving a single coil.
probably why the fet is massive - and not cheap!

[Scenic]

Re: APF PSUs and HEAT

antec smart-power uses a single fet driving a single coil.
probably why the fet is massive - and not cheap!

not-so-smart-power?

[stj]

Re: APF PSUs and HEAT

junk actually.

shit sleeve fans,
shit soldering.
shit caps.

it only sells because it has modular cabling.

[bigbeark]

Re: APF PSUs and HEAT

better out than in.
speedup the fans.

How do you speed up the PSU fans?

[shovenose]

Re: APF PSUs and HEAT

hook it directy to 12v source not throught the fan controller.

[goodpsusearch]

Re: APF PSUs and HEAT

hook it directy to 12v source not throught the fan controller.

You can do it but there will be a lot of noise..

[Th3_uN1Qu3]

Re: APF PSUs and HEAT

So WHY were these coils burned so badly?

I would think that a HOT APFC coil would indicate lots of current draw in the APFC transistors. Perhaps the main capacitor (270 uF/400 volts) is not handling the ripple currents from APFC which run at about 67 khz??? I have repaired some other psu with APFC problems and had bulging, leaking main capacitor.

Methinks it's simply a case of not enough turns or too thin wire. Copper is expensive y'know. The APFC circuit operates directly on AC, any filter capacitor will be after it and won't have anything to do with the coil.

If the APFC transistors are cool, current draw is ok. I've mentioned it a number of times already - grab the calculator off Micrometals' site, and it'll tell you exactly how hot it gets, why it gets hot and what do you need to fix it.