Antec Aria AR300 PSU Repair

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That was a good read. I have a lot of custom power supplies (not PC atx) that i would like to fix at work instead of replace, would be a lot cheaper (there's some high wattage power supplies that cost $5000 to replace). Need to convince the boss to buy a good oscilloscope.
 

Daniel Sauvageau

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All the standby power supplies I remember looking at are of the good old flyback design and one particularity of the flyback topology is that it has the worst ripple current on the output capacitors of all converter topologies or in other words: it is the harshest on output capacitors. Until I saw the waveforms while poking around the SL300, one little yet important detail skipped my mind: the harsh current waveform behavior applies to ALL outputs.

Any flyback supply with sub-par output capacitors on any of its outputs will inevitably fail in relatively short order.

After that 'oops' moment, I decided to pop the lid on my LG 204WT which I thought had dying CCFL tubes, popped three of its auxiliary supply capacitors off the board, measured them at 5-20 ohms of ESR, replaced them, no more flicker or random turn-on issues.
 

gnyff

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I love it when stuff is repaired! It's so sad that almost every consumer device today is made to fail and be replaced. Even in the cases where the designer did not specifically design for failure most commonly it's definitely not cost-effective for the user to have it repaired. :-(

Anyways, I've also replaced one of those lousy non-standard PSU. Hard to find and depressingly expensive. Thus, I am avoiding non-standard parts as much as possible now! ;-)
By the way, in one of my systems the standby power was around 12W (!) even after shutting off 5VSB functions (wake on LAN, keyboard etc) in the BIOS. I did on bother to investigate further (thinking "lousy supply"!) and simply added a proper "full off" power switch. Probably other owners should think of doing the same ;-)
 


I wonder if a SFX PSU could be mounted in those cases. Might be a viable solution...
 
Another great one!

I actually was interested in that case back when it was released, but just kept rocking the Sonata and Sonata II. While my power supplies did not fail. caps leaked after a while(power supplies still worked)and I took the power supplies out of service forever.

Rookie_MIB,
SFX would be an interesting idea to see for sure. My SFX is still going after 5 years of 24/7 operation(not bad for a case included 300 watt unit).
 

Daniel Sauvageau

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The dimensions might fit but mounting holes would be on the wrong side (for mounting in a way that might fit internally) and the IEC socket would face either the motherboard or the top cover. Nothing some drill-and-tapping with some wire splicing cannot fix for people who would favor this route instead of a repair of the existing unit where that is possible.

BTW, the total repair cost for the 5VSB side is about $1.50 for the caps and resistor. The rest is basically free since I scavenged the SCs from a dead (catastrophic primary-side failure) PSU and would have cost around $2.50 otherwise. If Asus had specified higher quality parts from Channel Well though, the PSU may have cost less than $0.50 extra to get right on the first try. Evem doing as little as specifying Teapo SC as the minimum requirement would have easily doubled the trouble-free service life over using SEK..

It always bugs me when only a few pennies worth in parts and materials can spell the difference between a product that might only last 2-3 years and a product that should easily last 10+ years.
 
That small cost per unit adds up.

I can not count the number of times I say, gee a xx cent part would have solved this damn issue and yet no one does it.

Drilling and making it fit is no issue. :)

I still get my small system fix with an SG05 case.

Where do you get your parts from? Digikey is not too expensive, but many times the shipping cost more than the parts(especially with resistors that are cheap to begin with.).
 

Daniel Sauvageau

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The "small cost" may add up but if you charge $1 to put the $0.50 worth of better quality parts in, you still make a 100% profit on that extra cost and you score points in the quality/reliability column. For the most part, those better quality parts are the same physical size, so no fitting or PCB layout concerns there.

As for where I get my parts, they are mostly Digikey. I either lump my order with parts I need to repair something for someone else (and pass the shipping cost to them) or build my order for multiple non-urgent projects until it qualifies for free shipping.

Edit: and for things like 0805 resistors and capacitors, I usually order in cut-tapes of 100 since we're still only talking $1-2 there. If I had more storage space, I would order whole reels for $10-15 (2000-3000 units) and likely never have to worry about ordering more of that resistor or capacitor value (for personal use) for the rest of my life.
 
I often repair computer power supplies and I enjoyed reading this article. One comment, that may help others and may explain some things in the article such as the power reduction of the fixed power supply.
Capacitors with high ESR always have a very high leakage current near their rated voltage. The leakage current at low multi-meter voltage levels is not normally measurable, but increasing the voltage across the capacitor dramatically increases the leakage. Circuits with capacitors with high ESR in them normally fail not due to the ESR or the reduction of capacitance, but due to the high leakage current. If you do not have a ESR meter you can simply put a suspect capacitor across a power supply at its rated voltage and check the leakage current. A high leakage current is a good indication of a high ESR value.
I use a in-circuit ESR meter to test all of the electrolytic capacitors (even the small ones) before I even start trying to fault find a power supply.
 

Ohh I agree. I would pay more for better parts, but many will not.
 

Daniel Sauvageau

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If there was truly massive leakage, the leakage would effectively clamp the voltage well below 27V and the voltage would decay to 0V instead of 5V. What you are seeing in my first scope picture is the i(t) * ESR of the flyback transformer's output current added on top of the capacitor's ~5V.

I did measure the leakage of a handful of those capacitors by applying 12V to them and none of them was above 1mA for the 10V ones despite the 2V over-volt. For the 50V ones, leakage was only in the microamps. While this is two or three orders of magnitude worse than spec in most cases, this is nowhere near as much as the 100mA draw from the 51 ohm dummy load resistor on the 5VSB output and would have negligible effect on the 5VSB circuit's operation and is effectively negligible.

Leakage was definitely not a significant factor in either the SL300 or AR300. Loss of nominal capacitance and high ESR were - not many circuits will work properly on a 5V supply output with 10-22V of ripple+noise from the flyback transformer's output current and capacitor ESR.

BTW, in my SL300 repair, a "massive current leak" is effectively what I created by using a TL431 + TIP42 to clamp the transients closer to 5.2V, drawing 3-4A peaks in the process to stabilize the 5VSB output and make the PSU turn on..
 

f-14

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great article
for the missing capacitor you need try the ATI 4850 512MB video cards:
I could not find a direct replacement for the 10mm 4700µF Fuhjyyu TMR, so I just slapped one more 2200µF SC in its place. At a glance, it seems 2200µF is the largest capacitance most manufacturers offer in 10mm diameter low ESR format with 10 to 16 volts rating.

as for that cpu cooler problem in the aria would this cpu cooler fit? Thermaltake / Ruby Orb / Socket 775/754/939/940/AM2 / Aluminum ...
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2844209
Heatsink Dimensions 140 x 140 x 73.3 mm
RPM 1700 RPM
Air Flow 77.85 CFM
Noise Level 17 dBA
 

Daniel Sauvageau

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Northwood = S478 with the cam-lock HSF retention mechanism, none of that push-pin rubbish.
 


Well, I have to build out a computer soon and I might utilize that spare case. I have a SFX PSU at home, maybe I'll take a look and see what kind of work it would take to adapt it. I already know that the mounting is going to have to get a bit creative because of the average length of the SFX main ATX connector. I'm just a little miffed that they went and used a non-standard PSU instead of fitting it for a SFX in the first place. Lets be honest, most people wouldn't use these for anything more than a simple, basic web surfing/office machine because of the mATX limitation on the board and the very shallow depth for any video cards.
 
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