Which of these psus is the safest?

[goodpsusearch]

Re: Which of these psus is the safest?

Measured one more psu at my main pc. It is maxpower 300watt no pfc from page 2, bottom post. (https://www.badcaps.net/forum/showth...1&page=2&pp=20)

Maxpower 300watt No PFC @ athlon XP 2200+ 1GB DDR 600MHZ, ATI 4650 AGP, 2xIDE 7200 and 2xDVDROM/RW:
V-------------------------Idle---------------3DMark05
5vsb--PCoff:5.10-5.11-5.05-5.06--------5.03-5.05
12V----------------------12.67-12.79-----12.90
12VB*-------------------12.69-12.70-----12.88
5V------------------------4.98-5.16--------4.97-5.05
3.3V---------------------3.32-3.33--------3.32-3.33

*mobo connector

This is definitely the next that will be donored after codegen lol.

[370forlife]

Re: Which of these psus is the safest?

12.9V is enough to fry your computer if you let it run that way too long.

What are you using to measure this? If you are using a DMM, maybe it is going wonky.

[goodpsusearch]

Re: Which of these psus is the safest?

12.9V is enough to fry your computer if you let it run that way too long.

What are you using to measure this? If you are using a DMM, maybe it is going wonky.

I'm using a digital polymeter. Values can't be wrong, because similar ones are measured by the mobo sensors.

[370forlife]

Re: Which of these psus is the safest?

Well, the mobo voltages aren't always right. Infact they almost never are. I have had multiple boards report 9-20V wildly on all rails, as have many other people.

(a lot of people complaining on JG or techspot or other places that their 12v is at 10v or so in the bios, blah blah blah...)

But if, what I think you're trying to say, a digital multimeter is confirming them, you might want to look into it. Something is not right there. What really confuses me is that marcon should have OVP, either it dosen't or it must trip at a really high voltage then.

[i4004]

Re: Which of these psus is the safest?

that's not macron, but maxpower.

where is OVP usually set (when it exists)?

i doubt it's on 12.5, so probably 13V?

why do you think 13v will fry something?
and what do you think will it fry first?

somehow i doubt 13v would fry hdd or mobo...

[370forlife]

Re: Which of these psus is the safest?

that's not macron, but maxpower.

where is OVP usually set (when it exists)?

i doubt it's on 12.5, so probably 13V?

why do you think 13v will fry something?
and what do you think will it fry first?

somehow i doubt 13v would fry hdd or mobo...

I think you're right. Most of the chips I have been looking at in psu's have the OVP set to about .95v - 1.15v or so about the normal value.

Theres a reason the intel spec calls for a max of 12.4v. Any higher and it starts to cause excess heat and degrades parts much faster. While it may not instantly fry it, it will cause shorter life.

[i4004]

Re: Which of these psus is the safest?

intel vrm design guide also says vrm should not start at all if voltage in not within specs it can work comfortably with.
(vrm is simillar to smps..it probably has some tolerance on its input voltage)

and if vrm don't start, then there won't be much damage as mobo won't be used at all...hehe....

that said, i would also aim to have 12v as close to 12v as possible....
it indeed is one crappy psu nobody should use....
not even as a gift...heh

[goodpsusearch]

Re: Which of these psus is the safest?

I once connected a linkworld 250 watt (not in this thread's list of psus) at my pentium 3 board to test it. It's 12V output was 13.8volts!

Happily, mobo and everything else connected to it survived. After a recap of 4 bulging caps with good ones I have taken out from macron and antec (would not do a full recap and would not waste quality caps for it), now its 12V output is 12.52-12.54, when connected at athlon XP. Still high, but not insane.

All of the above was made for experimenting.

edit: Macron Power is the best among all 300 watt psus in this thread. Very nice design and behaviour

BTW I said several days before that macron made a high pitched sound right after recap. 2-3 days ago all noises and sounds coming from it magically disappeared! I think the capacitors "burnt in"..

[goodpsusearch]

Re: Which of these psus is the safest?

that said, i would also aim to have 12v as close to 12v as possible....
it indeed is one crappy psu nobody should use....
not even as a gift...heh

That friend of mine, the one I gave codegen to, has 2 old pcs, a pentium 3 800mhz and a pentium 4 1.5. I think codegen could work at pentium 3 800mhz that is 5V based and very low power system, for some time.

As for the maxpower 300 no pfc... I just hope it's made for 12V pcs, like pentium 4.

They will be tested and measured with polymeter before I let him use them.

[i4004]

Re: Which of these psus is the safest?

>BTW I said several days before that macron made a high pitched sound right after recap. 2-3 days ago all noises and sounds coming from it magically disappeared! I think the capacitors "burnt in".

excellent.

btw. how did you measure these voltages, where and how?
spiked the cable with needle, or?

i see you typically measure only one voltage on the mobo connector..
others?

[goodpsusearch]

Re: Which of these psus is the safest?

12VB: red needle -> yellow cable at atx connector, black -> ground
5vsb: red needle -> cable bellow yellow at atx connector (color varies), black -> ground
3.3V: red needle -> orange cable at atx connector, black -> ground
12V: red needle -> yellow cable at molex connector, black -> ground
5V: red needle -> red cable at molex connector and red cable at atx connector, black -> ground

[momaka]

Re: Which of these psus is the safest?

Can you locate the 5vsb section in the photos posted please?

Sorry I couldn't reply earlier (almost end of the semester for me ).
Anyways here you go:
https://www.badcaps.net/forum/attach...id=12901&stc=1
Basically, transistor 1 takes DC current from the big caps on primary and chops it into AC by turning on and off very quickly. This AC current is then sent through the 5vsb transformer where it gets converted from high voltage to low. After that the current is rectified into DC again by a diode (you can see part of it right above the 5vsb transformer). There's also probably a capacitor or two and an inductor behind the diode (you can't see them on the picture) - those filter the rectified 5vsb DC before it goes to your computer.
In order to get a steady 5v for 5vsb, the circuit needs to regulate itself. In a 2-transistor design, this is done through a small 4-pin device, called an optocoupler (should be right next to the 5vsb transformer, though it's not visible on the picture). The optocoupler "sees" what voltage is present on 5vsb (i.e. is it close to 5v) and then "tells" transistor 2 whether the voltage needs to go up or down or stay the same. Transistor 2 in turn controls transistor 1 by "telling" it how fast to turn on and off.
Problem with this circuit is that the regulation of 5vsb relies on one critical capacitor (usually 10, 22 or 47 uF). When this cap goes bad, 5vsb voltage can go well beyond 5v and possibly kill your motherboard. Of course, depending on the circuit is built, it usually takes some time before the critical cap goes bad. If that capacitor is not abused (i.e. there's little heat where it's placed), then the PSU can survive for many years before 5vsb goes bad. But if that capacitor is next to a hot component, it could easily go bad in a year or two.

Hope this helps .
I didn't derail the topic too much, did I?

What about the caps? Is junfu good, bad or mediocre?

Can't say for sure. Had some fail faster than Fuhjyyu in one PSU, and some running many years in another (both were crappy PSUs though, so that shouldn't say much). I guess mediocre at best...
If they're the high voltage ones, though, they might be okay (at least for a while).

[i4004]

Re: Which of these psus is the safest?

>Basically, transistor 1 takes DC current from the big caps on primary and chops it into AC by turning on and off very quickly.

chopping it is not enough to make AC, as just chopping would produce pulsating DC.
inverter fits in there somewhere.
<wink>

[momaka]

Re: Which of these psus is the safest?

Oh I'm pretty sure if you dig more in my post above there's probably way more to it than that.
Then again, I've taken only one Electrical Engineering class, and that knowledge isn't even from there so don't expect too much from me .

[goodpsusearch]

Re: Which of these psus is the safest?

Thank you momaka for that very explaining post I was so influenced that I looked for +5vsb components at every psu I got!

One more thing... Today I went at my friend's home (the one I gave codegen 300 and maxpower 300 noPFC).

Codegen is performing nicelly at his pentium 3 800 system. 5vsb was at 4.97, +5v was ~5, 3.33 in specs too and the questionable 12V rail was steady at 12.23-12.24. Steady voltages and in range, I think it does for the job.

On the contrary, if you remember, maxpower 300 watt without pfc (bottom of page 2), it was out of specs when powering my athlon XP system, his 12V rail managed to reach 12.9V!
When put in my friend's pentium 4, his 12V line was in specs (11.80) but 5V was 5.30V... I took it back as it could not be trusted to power his P4. Any ideas why so bad voltage regulation, and how could it be corrected?

[370forlife]

Re: Which of these psus is the safest?

Must have some of the worst designed group regulation.

[goodpsusearch]

Re: Which of these psus is the safest?

So there is no (easy) way to make its outputs be in range? It's not worth spending time on it?

[momaka]

Re: Which of these psus is the safest?

Most likely not (unless you want a project that will give you a headache ).
Also, ask the question this way - is it worth loosing a computer over a crappy PSU?

[goodpsusearch]

Re: Which of these psus is the safest?

Waiting for replacement caps for Jou Jye Electronic JJ-460PPSA , I came to see many identical power supllies, all 2007/03 made, having exactly the same capacitor bulging: 1x1000uF 16V Capxon, as seen at 2nd photo here.

Maybe this is a warning sign that there was a design flaw at these supplies... Maybe too much heat? I don't know... Is there anything I should do?

[goodpsusearch]

Re: Which of these psus is the safest?

Hi.

Replacement caps for Jou Jye Power Supply (post#66) have arrived, but before recapping, I am concerned about 2 issues with this unit:

Here is a photo of the psu out of metal case

The first thing that concerns me is the area among bridge rectifier and first big cap. There is board discoloration, due to heat, visible from both sides of the supply ( upside , downside ). Some big resistors and 2 diodes are found there and very close to them are placed 2 jun fu caps rated 2.2uF 400V.. I desoldered 1 of the caps and measured its esr and capacitance: capacitance: 0.7uF, esr: - (maybe too big to be measured?).

I think that this is bad design, as this area's veltilation is blocked by heatsink, big 1000uF capacitor and bridge rectifier, seen quite clearly here . What's your opinion? Is there anything I could do to reduce heat in there? Or just, replacing with quality caps could be enough to run safe?

Second problem is a bit more complicated. As stated in the post above, I have seen many jou jye power supplies, same model, all having the same capacitor leaking, a capxon 1000uF 16V, measured 0uF, "R only": 3ohm.

photo1, photo2

It's one of the 2 5vsb caps, this one is placed in the circuit before filter coil and the other is a jun fu 1000uF 10V placed after the coil, esr and uF tested ok.

Heat problem again? There is a big resistor near the cap, but no discoloration here.. Why they fail in all psus I have seen?

I hope I get your advice..