Coolmax V-500 quality power supply

[everell]

This Coolmax V-500 ATX power supply recently came my way. Initial look revealed that the fan was stuck. As can be seen from the picture, the label says "Quality and Performance". Took it apart, cleaned the shaft and bushing, oiled it, and now it works fine. Most of the output capacitors were bulging, so did a recap using measured pull-out capacitors. The 3.3 volt and 5 volt outputs have pi filters, but the 12 volt output has only a single 3300 uF/16 volt capacitor. Perhaps OK for an older computer but not much to my liking. Biggest problem was all the burnt glue covering the top of the pc board and components. Lots of scraping, looks much cleaner now. Even a Bestec does not have this much glue. Coolmax is not my favorite power supply. What I am wondering now is......will it do 500 watts as the label suggests.......or will it do 400 watts? I am not holding my breath to see!

[Pentium4]

Re: Coolmax V-500 quality power supply

Good work everell It looks to be ATNG or Long Yi Power. That fan is most likely a rebranded T&T. They fail all the time. 20A ultra fast on the 12V? I'd say 350W tops IF those bulk caps are actually 560uF. And those TO-220 13009's might not even be able to do that since the heatsinks aren't that large. So, 300W continuous, 350W peak would be my estimate. I actually think the 3300uF cap on the 12V would keep things in tolerance up to 20A. But yes, PI filters should always be installed, especially on the 12V!

[stj]

Re: Coolmax V-500 quality power supply

lol
same design you just posted in the other thread!

[c_hegge]

Re: Coolmax V-500 quality power supply

Yeah. I would say about 300 too (assuming 12A BJT switching transistors). And yes, T&T fans are pure junk. It was one of those than failed in a Delta GPS-300AP I posted about a while back and turned the PCB completely black.

[mockingbird]

Re: Coolmax V-500 quality power supply

Ideally, a high quality sleeve-bearing fan should posses the following traits:

1) rubber o-ring beneath the snap ring that sits between it and the sleeve.
2) rubber o-ring on the other side of the shaft
3) cap that seals off the inside, good sticky seal on top. I've found that a sticker itself without the cap is insufficient. The adhesive finds its way into the lubricant and contaminates it.

Now there are well-molded (and I mean made using smooth molds and high-quality plastics) fans that lack some of these things, and there may be cheaply molded, low quality plastic fans that have all the above attributes.

The lubricant of -ALL- middle-tier - that means to say - Taiwanese/Chinese fans (even of good quality) is always of poor quality. You can get 5 years or more out of it, but despite the recommendations here of not replacing the lubricant because of the fear that it might react with the lubricant in the sintered metal sleeve bearing, I've never had this problem, and good silicone lubricant has always worked wonders for me.

[stj]

Re: Coolmax V-500 quality power supply

teflon loaded would be good, but cost more than the fan.
i see a lot of clip-together fans now that dont have a clip on the shaft - you cant even get to the shaft without a drill.

[budm]

Re: Coolmax V-500 quality power supply

Magnetic bearing, I use SUNNON in our products.
http://www.hardwaresecrets.com/print...uter-Fans/1039

[everell]

Re: Coolmax V-500 quality power supply

Here is another Coolmax I recently acquired. Supposedly rated for 400 watts. Didn't look like it had as much potential as the power supply in the first post. Haven't done anything with it except to put it aside for a cold snowy day.

[stj]

Re: Coolmax V-500 quality power supply

that's um - minimal on parts.

still, atleast you can see everything, unlike a pair of maybe chieftec's i recapped recently that where so packed it was a pain.

[Pentium4]

Re: Coolmax V-500 quality power supply

Same OEM that is now pumping out Diablotek units. Essentially useless for anything since there isn't even two caps per rail. Doesn't even look like there's a coil on the 5VSB filtering

[stj]

Re: Coolmax V-500 quality power supply

DevilTek? your joking right? dont they know what Diablo means!

[everell]

Re: Coolmax V-500 quality power supply

Same OEM that is now pumping out Diablotek units. Essentially useless for anything.....

So what's the beef with Diablotek power supplies? I have one and I think it looks pretty good. Decent heat sinks, current forward topology. decent output pi filters, decent sized transformers, and main filter capacitors are 1200 uF/250 volts. The thing I think is really cool is the little driver transformer to isolate the main pwm chip from the switching transformer. On cheapie power supply no driver transformer, and when the switching transistor shorts, it also takes out the pwm chip and lots of other parts. The label even boasts a three year warranty.

[kaboom]

Re: Coolmax V-500 quality power supply

The thing I think is really cool is the little driver transformer to isolate the main pwm chip from the switching transformer.

No, that's for driving the high side MOSFET. Looks like a dual switch forward converter.

One that's cheep enough to not have a dedicated highside driver IC.

Believe me, when the MOSFETs (yes, both) short, you'll lose the PWM IC- one MOSFET is directly connected.

The wire on the output inductors is way too small- clearly that thing's never been loaded to ~20A on +12.

Clearly a unit meant to be "dumped"- black and white line wires tells all. Whoever's behind that unit was thinking "there's nothing those suckers in the US won't fall for."


Deviltech...

"Warning: High voltage power supply,is not user serviceable. Please contact Service center for repair needs."

Service center:

[c_hegge]

Re: Coolmax V-500 quality power supply

^
Haha. I have to say, though, that, Everall's Diablotek unit looks like it might have a bit of potential. It's a 2TF design, not a Half Bridge. It might even do 450 or 500W in spec. I have a Cooler Power GX850 which looks somewhat similar internally (although mine had a PPFC coil screwed to the back exhaust grill directly behind the secondary heatsink, which would cripple the airflow.

[Pentium4]

Re: Coolmax V-500 quality power supply

Wow, that thing might even be able to do 40A on the 12V if the rectifiers are good enough. I was expecting worse.

[everell]

Re: Coolmax V-500 quality power supply

[QUOTE=kaboom;533378]Clearly a unit meant to be "dumped"- black and white line wires tells all.


I don't understand what bothers you about the black and white line wires. Black and white wires are standard color coding in the USA, black for hot and white for neutral. Or perhaps you are stuck on European standard, brown for hot and blue for neutral?

[everell]

Re: Coolmax V-500 quality power supply

No, that's for driving the high side MOSFET. Looks like a dual switch forward converter.

Believe me, when the MOSFETs (yes, both) short, you'll lose the PWM IC- one MOSFET is directly connected.

I removed the pc board from the case and have been tracing the circuit. The primary winding of that transformer connects to the pwm chip U3843. Each of the two secondary windings of that transformer connects to a FET. Unless the transformer shorts (which is possible) the transformer provides isolation between the pwm chip and the MOSFET switching transistors.

Shall we argue some more!

[Pentium4]

Re: Coolmax V-500 quality power supply

So what's the beef with Diablotek power supplies?

This is why.....This one was made in October, 2013. The label claimed 450W. Only one cap per rail, even the 5VSB!!! First time I've ever seen that.

[everell]

Re: Coolmax V-500 quality power supply

That looks like a "cool" power supply. It has TWO fan connectors! It even has an IC for the 5vsb circuit. But like the IMicros, only one capacitor for each of the output rails, and no line interference filter. Probably light weight, much lighter than my Diablotek power supply. I would judge this one as pos, but the one I showed earlier has far greater potential.

[kaboom]

Re: Coolmax V-500 quality power supply

[QUOTE=everell;534518]

Clearly a unit meant to be "dumped"- black and white line wires tells all.


I don't understand what bothers you about the black and white line wires. Black and white wires are standard color coding in the USA, black for hot and white for neutral. Or perhaps you are stuck on European standard, brown for hot and blue for neutral?

208Y/120 colors are black-red-blue-white, 480Y/277 colors are brown-orange-yellow-gray. Line-line-line-neutral. For 120/240 split phase, or 120/208 "network" service, only black and red.

AKA- Be Right Back, BOY.


My problem is that it's obvious that they're only made to be dumped on unsuspecting people- while those are in fact the right colors, they'd only be correct in a single voltage, US/Canada only device.

Now there's that selector switch, which changes the rectifier into a doubler for use on 120V. Either those supplies are 120/240V units, which they obviously are because of that switch, or they're 120V-only.

In any case, typical computer supplies are single phase only:
There's a single fuse- only one wire can be a hot. This means no US-240V split phase, where both conductors are hots.

Euro-240, while being the same voltage, is not derived the same way. A common example is a 416Y/240V, three phase, four wire, wye. Exactly the same type of transformer (or TX bank) as is used for our 208Y/120V services.

In that example, there too is only a single hot wire, so one fuse is fine.

They must figure "those Europeans will never mention those details." If they were honest and legitimate, they'd have the correct colors. There was even a time where the power switch broke both current carrying conductors- the humble AT "power-switch-on-leads" that you often hardwired to the front of the case.