5v rail to high

[Drack]

Re: 5v rail to high

We had 3 meters in my house, I had an analog that never worked like it should, and 2 digitals, one died after 10+ years of abuse(my dad dropped it a lot and the case was all broken) and the yaxun that is still working but it came missing one of the Ball bearings that make pressure on the dial and some black gunk that affected measurements.

[goontron]

Re: 5v rail to high

lol
you can never have too many meters.
i have 5.

I second that motion.

Ive got a digital Uni-T, an older analog RadioShack, and the good 'ol' Fluke digital.

[momaka]

Re: 5v rail to high

Update: the PSU is working fine, one of the DMM that I use to measure the voltages was bad and the other one had some dirty tracks on the PCB which affected measurements and a bad negative lead

Yup, most of my cheap multimeter do that. I just have to rotate the dial several times to clean the oxidized contacts. After that, they read voltage okay... provided that their batteries are also good, of course (low battery = high voltage measurement.)

you can never have too many meters.
i have 5.

You can say that again.

I have only 4, but two are Harbor Freight Tools freebies, so not great quality. Another one is a cheapie as well, but a little better than the HFT meters (and I put good probes on it, so that makes it considerably better ). So my only good meter is a Radio Shack one - the more expensive models (though I got it for cheap on eBay.) It's no Fluke, but it's a major step-up from any cheap or even entry-level decent meter.

[stj]

Re: 5v rail to high

lol
you can never have too many meters.
i have 5.

[Drack]

Re: 5v rail to high

Update: the PSU is working fine, one of the DMM that I use to measure the voltages was bad and the other one had some dirty tracks on the PCB which affected measurements and a bad negative lead, 12 volts it's actually 12.33 at idle and 12.16 at full load with prime 95 and furmark running and 5v is at 5.19 at idle and 5.27 at load everything stable, the capacitors are doing fine (at least visually) the PSU exhaust air is just warm so I think it'll be fine, also I only use this pic like 3 to 4 times a month. Again thanks for everything guys.

[Drack]

Re: 5v rail to high

Hi guys, did someone find anything about the psu?

[Drack]

Re: 5v rail to high

Sadly this is the only PSU I have, well I have others but they are worst than this , you can't buy anything better here without being rich and I don't think you could get an schematic, it's an Agiler AGI-ps1000

[Longbow]

Re: 5v rail to high

I'm still not buying it. I think it is time to name this supply and put up a schematic. These things are generally complex and well regulated supplies. True, they might need a simple load plug to actually draw a minimum current, but beyond that the 12v and 5v outputs should be right on.

It applied to picture tube tv's and it applies to switching power supplies: these flyback things are like a balloon. If you grab one part and squeeze it (tweak it), another bubble appears in a different place. The whole group of secondary outputs work together, even if they aren't on the same secondary winding. If looking carefully at the schematic doesn't get results, I would scrap this one for parts. That's my personal opinion.

[momaka]

Re: 5v rail to high

Also, if you really want the 5V rail to go down, you will need to put a much bigger load on it than just a fan or two. More like car light bulbs that eat up to 3-5 Amps total.

But I guess if everything is running stable, then just let it be then and don't modify anything. I doubt you will get any catastrophic failures.

[Drack]

Re: 5v rail to high

I don't think ripple is too high, it has 3 caps and one pi filter per rail

[Drack]

Re: 5v rail to high

I don't have an oscilloscope, and almost anybody in Venezuela have one, I measured with the DMM set to 20v d.c...

[Longbow]

Re: 5v rail to high

Think about it. I would start with the reference, which is typically in the secondary. In your case it monitors the 12 volt line. Don't forget to look at the ripple on the 12v. and 5v outputs. Are you really measuring a d.c. level?

[Drack]

Re: 5v rail to high

Someone?

[Drack]

Re: 5v rail to high

That's what is weird, when I putted more load on 5v the voltage went up, and I mean 5v, so I don't really know what to think, at idle 5v is at 5.236v that's a bit high already, what I can see over here is that if it's not touching 5.5v it should be OK.
Sorry if I'm bothering you guys I just don't want that cheap PSU killing my HDD or mobo
Ps. My Mobo is a ASRock g41m vs3 rev.2 by the way

[cpt.charlie]

Re: 5v rail to high

It's normal, "modern" CPU and GPU take the power of the 12V rail (even graphics cards without 6/8pin power connectors), so, in a group regulated PSU expect a voltage increase at 5V line, some load at 5V line should keep things under control, but you could consider other options like undervolting to decrease the power requeriments.

[Drack]

Re: 5v rail to high

I was watching the PSU and I saw that it does not have a feedback cable for 5v that might be why is to high because it's not monitored
And I don't know why but when I putted the fan on the 5v rail it went up and not down(from 5.256 to 5.280) but that's only at full load on the CPU and GPU. It was the opposite of what I was expecting... (Lol I think)

[Drack]

Re: 5v rail to high

Remember it has an 35 transformer so I think that would be too much load for it, and I would like to not disassemble this PSU because if it brokes I don't have a way to buy a new one, I'm only 17 so I can't find a job at this moment and that one was a gift

[momaka]

Re: 5v rail to high

It's possible that it was set wrong, but the +12V being low like that - close to the spec limit, IIRC - suggests the system load is 12V heavy and 5V light.

11.7-11.8V on the 12V rail is not that low at all. My 250 HiPro PSUs typically run in that ballpark too with a high-TDP Pentium 4 CPU, like the 89 Watt Prescotts.

What I am more worried about is the high 5V rail. Some motherboards do NOT regulate power going to the LPC/SuperIO chip, and those are sometimes rated for 5.5V max. So staying close to 5V is better.

One easy way to lower the 5V rail is to put some 20-40 Watt car light bulbs on the 5V rail. The increased load should lower it a bit, hopefully, and possibly bring the 12V rail output up.

Another method would be to tweak the feedback in the PSU to lower the output voltages a bit. That way, both the 5V and the 12V rails will get lowered.

And yet another way... though this one is a bit more experimental... would be to change the 5V Schottky rectifier in the PSU with a fast-recovery type. Something like a F16C20 should have a much higher voltage drop and will bring the 5V rail down. Of course, this will also bring down the PSU efficiency and make it run a bit warmer too. But if you are only going to use this PSU with a 12V-heavy / 5V-light computers, then that should not be a problem.

[Drack]

Re: 5v rail to high

I know, maybe 4 amps on 5v and like 24/26A on 12v, the minimum allowed by ATX specs is 11.4v so nothing to be worried about

[PeteS in CA]

Re: 5v rail to high

It's possible that it was set wrong, but the +12V being low like that - close to the spec limit, IIRC - suggests the system load is 12V heavy and 5V light.