Re: Dell Power Supply NPS-250KB B



so the LM324 is used for overvoltage protection, that leaves the dl 1001/2 I forgot the exact number, which is located on the daughter board for voltage regulation, I suppose.
I am not familiar with those softwares, for schematics thou I will look into it,
I noticed that from each power output there are 2 paths 1 to the lm324 one to the dl1001, on the daughter board there are several surface mount resistors, I assume this is the voltage regulation circuit, now where to install a pot and what size I have yet to figure...

Re: Dell Power Supply NPS-250KB B

I do apreciate the interest and the input, I shall read up on those new links see if I can figure this out, in short, I am not very good with electronics, couple weeks ago I did not even know what a power supply is made of, I do know electricity and basic princyples, and I have read a fair bit to get familiar,
I have seen some meanwell units that were done, and also some atx, figured this one should be no different thou it seems to be a bit more complicated, if you would indulge me. what do all these stand for:
asic, pwm, pfc bit new...

Re: Dell Power Supply NPS-250KB B

found this [url]http://www.thebackshed.com/forum/uploads/oztules/2009-06-05_210459_1002.jpg[/url] does it mean anything to anybody?Re: Dell Power Supply NPS-250KB B<br...ng to anybody?Re: Dell Power Supply NPS-250KB B

found this [url]http://www.thebackshed.com/forum/uploads/oztules/2009-06-05_210459_1002.jpg[/url] does it mean anything to anybody?

Re: Dell Power Supply NPS-250KB B

so i suppose nobody knows any better, as to where the voltage/curent is regulated on these units, guess I'll give it a go see what happens

Re: Dell Power Supply NPS-250KB B

I'm either on my own, you all think I am nuts and about to fry myself, or got no good advice ( i'd like to doubt that last one ), or maybe I am just beating a dead horse.
I gave up trying to find a schematic, there just isn't one, nor a datasheet for anything on this unit, must be an industry secret, so in lack of other options, I have been tracking the circuit board trying to understand it.
based on the little theory I know, I noticed 2 paths, from each output, one to the sister board one to the optos, the 5v and 12 v make it to the...

Re: Dell Power Supply NPS-250KB B

ok so I figured out what an opto coupler is supposed to look like, and I think I found the 4 in question, see pics, there are several resistors leading up to them, but which one is which beats me,
that beeing said, based on some generic diagrams and schematics I came across, the chip to the left is the controller? I tried checking voltages on it before, but looking back I think it operates in ac, it is on the highvoltage side, wasn't getting any readings dc.
what am i looking at here? changing the resistor values before the optos,...

Re: Dell Power Supply NPS-250KB B

[url]http://www.youtube.com/watch?v=mK_rIs7uFlo[/url]
here's another example, for some reason they are all atx, not that I could make much out of the video, but that is the Ideea I am trying to accomplish, for some reason, with 1 pot he can regulate all output voltages, I know for the most part a voltage regulator is controlled by 2 resistors, a pot could make that adjustable, now little that I know, I would say the pot max resistance should be about the same as the 2 stock resistors, if wired right should be able to vary the resister values,...

Re: Dell Power Supply NPS-250KB B

oh and I touched some of those surface mount resisters on the daughter board with a screwdriver, the draw from the extra metal was large enough to cause a voltage drop, to 8v on the 12v output, unlike other silly experiments, it did not trip the psu, as soon as the screwdriver was removed voltage went right back up. therefore I feel I am on the right track but again this is not science, pocking things and see what happens.
there is also a meanwell supply mod that I read about that inspired me to tinker with this
[url]http://endless-sphere.com/forums/viewtopic.php?f=2&t=42793&p=653187&hilit=meanwell+mods#p653187[/url]...

Re: Dell Power Supply NPS-250KB B

bump.

I know there is a wealth of knowledge among your circles, and what I am trying to accomplish is a bit unconventional to what you boys do for fun, I could use some insight here before I do something silly and blow this thing up, I took some pics and poster them here [url]http://s1365.photobucket.com/user/2007blueprius/library/?sort=3&page=1[/url]
I am not sure what the chip on the main board does but I measured some voltages and this is what I got:
voltage readings, starting at pin #1 top left, they changed...

Re: Dell Power Supply NPS-250KB B

Do you mean that it's working but you're trying to improve upon the voltage regulation? I wouldn't be worried about the voltage regulation on any of the rails unless it's out of spec. Unless you need to because you're using the PSU for other means (if I read correctly). The amp output should be as the label says - 18A on +3.3V, 22A on +5V, 14A on +12V, 1A on -12V, 2A on +5VSB, 170W for +3.3V and +5V combined maximum, 250W maximum.[/QUOTE]

not necesarrely improve, more like change, and yess you guessed right, the supply was working...

Re: Dell Power Supply NPS-250KB B



I am tinkering with the exact model and quite honestly I don't know exactly what I am looking at, but I am trying to get the voltages slightly adjusted, preferably the amp output too, problem is I am kinof clueless, haven't been able to find a diagram I am guessing,
up untill I cam across this post I thought the dna1002e on the sister/daughter board might have something to go with voltage regulation, I see there are lines comming from all 3 outputs to it, the 3.3v goes through a resistor, the 5 a jumper, and 12 goes straight...