Got a cheap supply for free with bad output 5.8 Volts on the 12 volt rail and 2.5 volts on the 5 volt rail..Iam not planning to use it with a system just want to use it for other purposes..Can it be fixed???
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Re: Cheap Supply
best fix is to use it for educational purposes.
troubleshoot it to learn only.
then toss it.
its a typical powmax gutless wonder.
only value is scrapmetal. -
Re: Cheap Supply
How to fix it???
Any idea!!!Comment
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Re: Cheap Supply
how to bring the 12V and 5 V rail back onlineComment
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Re: Cheap Supply
Do the output voltages hold steady or fluctuate?
If they hold steady you're probably looking at a feedback problem.Elements of the past and the future combining to make something not quite as good as either.Comment
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Re: Cheap Supply
Output is dead steady.Comment
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Re: Cheap Supply
Then I'd check the feedback sampling circuits for shorted or off value resistors.
If that reveals nothing then the issue may lie inside the PWM IC.Elements of the past and the future combining to make something not quite as good as either.Comment
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Re: Cheap Supply
Check or replace that fuse. Looks like it might be on its way to being blown. Measure voltage on either side of it to see if there's a partial drop, and check resistance through it. I've seen fuses partially fail during a power event and then only allow partial current/voltage through.Ludicrous gibs!
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Re: Cheap Supply
No way I had that happen once too I was so embarrassed when I found it out.
Good observation I hope that the discoloration on that fuse is dust and not vaporized filament
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I've read that the theory is the fuse filament vaporizes on the glass fuse body making a resistive electrical connection across the fuse body allowing the current to still flow at reduced capacity (due to the resistance).
It was on a 5.1 audio amp the fuse was an axial type incased in one of the transformer secondary wires.
When I finally broke down and cut off the heat shrink tubing I measured a resistance.
If you want to do it in a safer fashion measure for resistance across the fuse.
Any DECENT power supply would actiate undervoltage protection in this case shutting the supply down. If that isn't a sign to junk it then I don't know what is.
There are plenty of cheap ATX psu's to be had that are way better designed than this one.
But if it's just to see if you can get it working keep posting results.Last edited by Krankshaft; 07-23-2008, 11:43 AM.Elements of the past and the future combining to make something not quite as good as either.Comment
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Re: Cheap Supply
Never heard of a half blown fuse before.
That is extremely odd.
I'm very familiar with magnetic or thermally operated circuit breakers that no longer hold on under load, but I always thought a fuse was either go or no go.JimComment
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Re: Cheap Supply
This is a different fuse and a different situation but here is my story. Back in the mid eighties I had a nice 71 Datsun 510. One day it was snowing like hell and was about 21F outside. On my way to college the heat stopped blowing. That evening on the way home first one headlight went dim, and a few mile after that the other went dim too. Pulled into this gas station the do a quick check and found 14.7V at the battery with engine running and 12.2V not running. Ok the charging systems working OK. So next I opened the fuse block under the hood and they all looked good! They were the old glass tube type fuses. I pulled the heater fuse and its metal end cap fell right off. The element looked perfect but it had detatched at its termination at the cap. The A---holes at that station charged me $3.99 for one fuse! Anyway I stuck that new fuse in and the heater started blowing again! Yes I went back in and bought the two headlight fuses, and they came back to life too. All the fuses had the same problem at their ends. It still pisses me off that I had to pay $12.00 for something that should have cost $1.50. Yes checkout that fuse."It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so."
Mark Twain
"I wish to have no connection with any ship that does not sail fast; for I intend to go in harm's way."
John Paul Jones
There is a fifth dimension, beyond that which is known to man. It is a dimension as vast as space and as timeless as infinity. It is the middle ground between light and shadow, between science and superstition, and it lies between the pit of man's fears and the summit of his knowledge. This is the dimension of imagination. It is an area which we call the Twilight Zone.
Rod SerlingComment
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Re: Cheap Supply
Thats why it's said that fuses aren't 100% reliable in most situtations they will blow as planned however in certain instances they won't.Originally posted by arnesonElements of the past and the future combining to make something not quite as good as either.Comment
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Re: Cheap Supply
eh, junk parts...those 10.5$ would surely make you a millionaire today....hehe...Comment
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Re: Cheap Supply
How can I test the PWM,its a AUK S494PComment
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Re: Cheap Supply
Found The Problem!!
it wasnt the Supply it was ME
,I was shorting the wrong wires to turn the PSU ON,instead of shorting the Power On wire with Ground i was shorting it with the Red(5v) wire.But now after fixing this the Supply wont even turn On the fan spins for a second and then turns off.
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Re: Cheap Supply
hook a harddrive to it and try again.
many power supplies need a minimum load.Comment
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Re: Cheap Supply
No matter whatever i attach with the supply it still wont turn ON
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Re: Cheap Supply
Tested the switching transistors and the Standby voltage,its fine.Comment
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Re: Cheap Supply
Interesting Find!!
After removing the COSMO 1010 817 Photocoupler the PSU starts up normally. Iam pretty
righ now about what the problem might be??
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Re: Cheap Supply
Get the datasheet of your monitoring/protection IC. If the `FPOB` pin is connected to the Opto, then the PSU starts because you have effectively disabled the output fault protection signal. It`s hard-powered on.
You should be careful that your voltages etc are OK, as your PSU is now not fault protected.
Consequently, if your outputs are OK, then you have a faulty protection IC or Opto.Comment
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I saw this switching power supply on eBay and wanted to see if could be modified to run 14.5 volts before the blocking diode was add and this switching power supply seems to have no issues doing this
I did recap the switching power supply except the the main filtering capacitors and I managed to break the selector switch for the voltage setting but just jumped it
One note I used 25 volt capacitors on the output side of this power supply because they used 16 volt capacitors and because I am running the voltage up a little bit higher 12 volts to 14.5 volts there would... -
I have been wanting to do this project for some time using a Mean-well switching power supply that I bought at least ten of them that were originally in a device that was abandoned for some reason they were listed new but removed from equipment that was never used
I do not understand Mean-well the capacitor next to the voltage reference ic chip was a brand that is known for failure over time the other capacitors are brand name needless to say it got replaced before I even powered it on for the first time
I used a four USB outlet and electrical plate that is made for... -
I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump
One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy... -
This is the switching power supply that is used in this project
https://www.ebay.com/itm/164440680270?var=464055952700
Here is the BMS protection board
https://www.ebay.com/itm/38688703079...iiBFn%2B3x1VjJ... -
Hi everyone,
Brought a non functionnal PS5. Apparently only a bad PSU...
No beep, nothing.
After some tests i found this :
- PSU is fine (12 volts stable)
- 12 volts line is shorted
- DA9065 was fried, F7003 also => Replaced both of them, short is gone on 12 volts line, no dead short anywhere else.
- By the way, nothing change. No signal, no power, no beep.
Mesuring all rails with my workbench psu (12 volts input)
- 0.00 amp drawing
- 12 volts, 5 volts, 2 volts, 1,15 volts are presents (suppose new DA9065 do is...
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