Antec smartpower 450W (SP-450p), working with missing components

[reaper57]

I got this Antec smartpower 450W (SP-450p), non working power supply, for free from a friend sometime ago. What I found in it, was a bad cap (EC10), which I replaced (picture No.1), a fried resistor (R11) and a shorted 1n4728a zener diode (ZD5). I did some research and I found that the resistor had a value of 5.6 Ohms. I'll post links to the forum threads that I found this information from tomorrow. After replacing the diode and the resistor, I plugged the power supply in and not very surprisingly, the resistor started smoking. I traced the traces and found that the resistor and diode are connected to one another as well as a MOSFET, which is between other components and I can't see its model, but it doesn't appear to be shorted. The resistor also goes to a CCM-PFC (ICE1PCS01) datasheet: https://cdn.badcaps-static.com/pdfs/...a448f3ad78.pdf
Now to my question. Because I couldn't find any faulty components I desoldered the diode and lifted one of the resistor's legs and the power supply worked! I tested it in a PC running prime95 and furmark and it ran stable for about 30 minutes. Why is this happening? Isn't the CCM-PFC mandatory for the operation of the PSU? Or is it that these components are used for something different entirely? Also, do you have any ideas why the resistor keeps frying if connected? And one last thing, is it OK to use the PSU like this, if it's stable?

[stj]

Re: Antec smartpower 450W (SP-450p), working with missing components

pfc isnt needed to be running on 230v systems.
look at the schematic of any pfc datasheet.

it's a parallel circuit.
btw, i had a smart-power with bad pfc, the fet was shorted and the coil was cooked!!
they really are crap psu's

[fzabkar]

Re: Antec smartpower 450W (SP-450p), working with missing components

APFC appears to be an EU thing. Here is Australia it is not mandatory, AFAIK. We are still billed for real power usage (kWh), not apparent power (kVAh), so Australian domestic consumers derive no benefit from a unity power factor. The EU may be different. I don't know.

[stj]

Re: Antec smartpower 450W (SP-450p), working with missing components

we are billed by KWh

i'm starting to think it may have something to do with not interfering with smart-meters or power-over-dataline systems

[Behemot]

Re: Antec smartpower 450W (SP-450p), working with missing components

PFC has nothing to do with apparent power. This discussion repeats over and over.

SMPS create current spikes at the switching frequency, the higher harmonics go all the way to MHz range and that is some pretty nasty stuff for all the radio equippement and other instruments. It also creats problems with older motors etc. (IIRC some resonance or something like that with these frequencies creating local overheating which may damage or destroy them).

Similar resistors and diodes are usually used as safety precautions if there is some failure within the circuit. If you remove them it may work or it can also pretty much explode.

[Per Hansson]

Re: Antec smartpower 450W (SP-450p), working with missing components

PFC has nothing to do with apparent power. This discussion repeats over and over.

PFC is an acronym for: Power Factor Correction
"The ratio of active power to apparent power in a circuit is called the power factor"

[goodpsusearch]

Re: Antec smartpower 450W (SP-450p), working with missing components

lol

[Behemot]

Re: Antec smartpower 450W (SP-450p), working with missing components

Very childish indeed. You may realize besides the name it still has nothing really to do with it.

The goal is to get rid of the harmonics. Phase difference is only side effect and is not important at all. However, by incorporating extra circuitry in front of the SMPS, especially boost-type power supply which switches in phase with voltage, you get rid of the harmonics. As side effect, the power factor also improves.

The goal is important, not the side effect. But PFC sounds better that is where marketing took over.

[fzabkar]

Re: Antec smartpower 450W (SP-450p), working with missing components

See this discussion:

https://groups.google.com/forum/?hl=...Y/d7L-y-okW_4J

It explains how to calculate the PF of an active load such as those found in a typical PSU. There is a worked example that demonstrates that the phase relationship between current and voltage is not important in determining the PF for a non-linear load.

[reaper57]

Re: Antec smartpower 450W (SP-450p), working with missing components

So, if I use it at 230V it should be fine? If so, why only at 230V and not 110V? If it's not safe to use it, like this, why and what can happen? Also, is the PFC chip completely off, right now? I mean what are the other 5, (I think), pins used for?

[Behemot]

Re: Antec smartpower 450W (SP-450p), working with missing components

The voltage would most likely bee too low for the switchers to keep secondary voltage. But with 230 V after rectification the voltage is close enough to the original boosted voltage.

[Per Hansson]

Re: Antec smartpower 450W (SP-450p), working with missing components

Very childish indeed. You may realize besides the name it still has nothing really to do with it.

The goal is to get rid of the harmonics. Phase difference is only side effect and is not important at all. However, by incorporating extra circuitry in front of the SMPS, especially boost-type power supply which switches in phase with voltage, you get rid of the harmonics. As side effect, the power factor also improves.

The goal is important, not the side effect. But PFC sounds better that is where marketing took over.

Did not mean to sound childish at all, just had no idea.
Read up on it now and it's exactly as you say.
The EU directive for power factor correction in power supplies above 75w is infact about harmonics and not power factor as I believed.
Guess calling a horse a horse would have been too logical?

So, if I use it at 230V it should be fine? If so, why only at 230V and not 110V? If it's not safe to use it, like this, why and what can happen? Also, is the PFC chip completely off, right now? I mean what are the other 5, (I think), pins used for?

Measure the voltage on the bulk capacitor, with 230VAC feeding you will have: √2*230=325VDC
So if the voltage you measure is higher then the PFC stage is active.
The energy storage of a capacitor is related to the voltage.
So if you feed the single bulk capacitor with just √2*115=163VDC
That will not provide sufficient hold up time.
Remember that a SMPS can only charge the bulk capacitor when the incoming line voltage is above the voltage of the capacitor!
This is why a PSU creates the harmonics on the power grid to begin with, it only draws power at the peak of the AC voltage sine curve...

[fzabkar]

Re: Antec smartpower 450W (SP-450p), working with missing components

My thanks to Behemot as well. I found the following articles that explain the harmonics minimisation requirement:

https://en.wikipedia.org/wiki/Power_factor
http://www.rfemcdevelopment.eu/index...3-2-2006-a1-a2

However, I'm still left to wonder about appliances such as refrigerators, washing machines and air conditioners. AIUI, an AC motor would appear as a linear load, so ideally it wouldn't generate any harmonics, despite having a low PF. This suggests that a manufacturer would be required to apply PFC to the electronics in such an appliance but not necessarily to the motor. Is that what happens in practice?

[Behemot]

Re: Antec smartpower 450W (SP-450p), working with missing components

Did not mean to sound childish at all, just had no idea.
Read up on it now and it's exactly as you say.
The EU directive for power factor correction in power supplies above 75w is infact about harmonics and not power factor as I believed.
Guess calling a horse a horse would have been too logical?

Let me apologize than. This topics is constantly being discussed over and over, I have at least once explained that and with goodpsusearch and his trolol comments, I somewhat got the impression you are making fun of that…

fzabkar: motors are usually compensated with capacitors plugged in parallel, that is so for many years. Such caps also often serve other purposes, for example starting one in asynchronnous motor. Than overall the motor has PF closer to 1. But these things are easier to compensate; the total phase change of all the applieances in any area is usually constant of some average value so distributors may install huge phase shifters, either capacitative or inductive, close to any area (or even at local transformers/transformer stations). But harmonics create problems long before transformer station. Bigger, especially industrial customers are usually regulated to provide given PF and harmonics limit so those usually have active means at the connection point installed.

[fzabkar]

Re: Antec smartpower 450W (SP-450p), working with missing components

Perhaps I phrased my question ambiguously. I could be wrong, but it doesn't appear that there is any legal requirement in respect of the PF of a motor, even in the EU. I would have thought that such appliances would have a much greater impact on the electricity supply than a computer or TV.

BTW, I'm aware of start and run capacitors. I replaced enough of them in Control Data disc drives during the 80s and early 90s, but these motors would draw as much as 30A from 240V during startup, and about 3A or 4A when running.

[Behemot]

Re: Antec smartpower 450W (SP-450p), working with missing components

Not sure about home appliances, but definitelly industrial customers are obliged. Actually they are fined for low PF by the distributor company so it is in their interest…