600 watt Sky-Link Power SMPS Repaired
This 600 watt Sky-Link Power SMPS (China made) was brought to me by a fellow-worker with the complaint it could not switch on.
First thing done was to disarm it, a piece of cake, only four screws were holding the upper cover.
As you can see in the photo above there was a lot of cables coming out of the unit, remember it was a 600 watt unit.
I decided to test the voltages of the VSB: +5 volt (purple-colored cable) and the PS_ON: +5 volt too (green-colored cable) as you can see in the photos bellow. This situation has happened several times to me: VSB and PS_ON voltages ok, but the unit refuses to start.
As you can see in the photos above both voltages were ok, but the unit refused to start most of the times. Have a look to the photos below and look how dirty and rusted (I suppose it got wet with some liquid or maybe it was working in a place with a high humidity) was this unit.
After cleaning up the device the first thing done was to check on the e-caps with my ESR Blue Meter and look what was found.
Note: the second photo above was shot before cleaning up the unit.
Four e-caps (3300 µF/6.3 volt x2 and 470 µF/16 volt x2) were found bulged, and of course with a high ESR.
Anyway both of the big filters of the primary side were de-soldered and checked on too.
The four e-caps with high ESR were substituted for similar ones, and the big filters were re-soldered again. When the SMPS was switched on several times, it never refused to start and look the result.
This time the SMPS worked really fine and all the V-out were present.
This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.
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http://www.electronicsrepairfaq.com/maxell-usb-memory-repaired#more-1331
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Yogesh Panchal
August 25, 2017 at 3:20 pm
Good Job!Humberto
Humberto
August 29, 2017 at 12:20 pm
Thanks Yogesh
Albert
August 25, 2017 at 7:51 pm
Glad to see you are still repairing all sorts of devices Humberto!
Thanks for the well written article and good photos.
The repaired 600 Watt power supply is a newer 2 primary HV capacitor model of course, because they in the past only used 1 HV e-cap on the primary side.
Recently I opened and cleaned a similar 600 Watt power supply to replace the old noisy 12V DC Fan by another one. And the strange thing was that when I tested both the Fans on an external 12V DC power supply they didn't work at all! Although the current going through both 2 wired Fans was about 750 milli amps they just didn't rotate? Maybe it had something to do with the fact that they were inside the supply connected to a special small Fan controller PCBoard that was attached with one screw onto the secondary cooler plate? And they only did work when attached to this board. It is something that I have to look into more closely by examining the small Fan board. Also because I couldn't find any explanation about this strange fact on the internet.
Henrique Jorge Guimarães Ulbrich
August 25, 2017 at 9:54 pm
Albert, the situation you have related is really unusual. I also can't find a reasonable explanation.
Albert
August 27, 2017 at 10:21 pm
Today I rechecked the "Noise Limiter" aka Fan speed control board again of my friend's Power supplies. And found the simple reason why the Fan didn't rotate on his external regulated Power supply. The reason was that both wires were reversed connected to + and gnd on the Supply. Which was not obvious at first because both wires are red of which the second one only has a thin black stripe extra.
Anyway even the Nasa makes mistakes and I only can say that I had not connected them. But now anyone knows that Fans do not rotate when + and GND are reversed, and not even the other way around. And luckily the Fan wasn't destroyed while testing although there was a current running of about 0.75A DC. In any case I only had connected it shortly to the external supply.
In the meanwhile if anyone is interested I now have made a drawing of the circuit of this Fan speed control board. Problem solved!
Humberto
August 29, 2017 at 12:24 pm
Thanks for your comments (Albert and Henrique).
Henrique Jorge Guimarães Ulbrich
August 25, 2017 at 9:56 pm
Saludos, Humberto. Glad to see you back again with your good maintenance articles.
Humberto
August 29, 2017 at 12:25 pm
My greetings and regards to you too
Parasuraman
August 26, 2017 at 12:28 am
Great work! I love servicing ATX SMPS Power supplies!
Humberto
August 29, 2017 at 12:28 pm
Thanks Parasuraman, I like a lot servicing PC SMPS too. A time ago I repaired a Hewlett Packard SMPS and it took me some days, but I really enjoyed and learned a lot that job. Thanks.
Robert Calk
August 26, 2017 at 12:30 am
Good job, Humberto.
Humberto
August 29, 2017 at 12:46 pm
Thanks Robert.
angelo
August 26, 2017 at 5:54 am
thanx for the article sir
Dear sir(s)
i need your kind help i got a psu named space 400w
the problem with the PSU is the fan rotates well without load
but when the PSU is connected to the pc and applied load
the pc simply keeps on restarting..
i opened the PSU on visual inspection did not find any bulged ecaps or
dry joints . but there was something unusual going on in the psu
which grabbed my attention . "there was some kind of noise or sound"
in the primary section
plzzzzzzzzzzzzzzzzz
sirs
help me
thank you
Humberto
August 29, 2017 at 12:59 pm
Some times that`s due to malfunction of the Operating System, but I recommend to you one thing: check this SMPS in another PC which be working fine.
Mugabira Paul
August 27, 2017 at 11:16 pm
Thanks for the well written article and good photos
Thanks for the work and i have learnt how to solve that issue
Thanks;
Mr Humberto Rodriguez
Humberto
August 29, 2017 at 1:00 pm
Ok Mugabira.