Looking for Dell power supplies atx machine diagrams ?

Other Hardware General Electronics
1

Power supplies atx computer desktops Model: H250AD-00, 5v power supply failure (green wire), STW9NK95Z mosfet front-end power supply and main STB23NM50N power lamp (other common circuits have two power lights The rectifier circuit is still working well, removing the STW9NK95Z from the circuit at G 0v pin, D 450v pin, S 0v pin, these two mosfets are still good but still no 5v green wire. How to check two ICs TNY274-280 and FAN4800A live or die ? http://www.mediafire.com/view/2fy27zkhhp7t19d/IMG_20180825_145242.jpg/file

2

Unfortunately, this is a very complex matter and unless you already have the expertise not to need to ask, likely by working with someone whose speciality this is, you are not in a position to repair SMPSs. :roll_eyes:

3

The "easiest" way is to replace parts until it works. The downside is that the existing problem may
cause the new parts to fail instantly, unless you were lucky enough to replace the right part first.

Testing all the passive components and replacing all the semiconductors is a fairly reliable strategy,
though probably more expensive than replacement of the entire unit.

Why you should imagine a volunteer answering Arduino questions is likely to be an experienced
SMPS technician is hard to fathom (such as as rare as hen's teeth in these days, where faulty units
are simply replaced.

4

Looking for Dell power supplies atx machine diagrams ?

Ask Dell ?

5

srnet:
Ask Dell ?

Well I doubt Dell know anything about the supply other than the specification they gave to the actual
supply manufacturer!

6

I know this work is very complicated, I am not professional like SMPS but if I have got the schematic of this power supply I will solve this problem, if I asking Dell, I do not think they provide because this is the Company confidential documents If you do not have this circuit diagram, I will look for another direction.

7

dongtrien:
I do not think they provide because this is the Company confidential documents If you do not have this circuit diagram.

If they are 'Company confidential' then it would likley be a breach of copywright law for anyone to give you a copy.

8

I have repaired a few SMPS supplies so far and i tend to follow the following strategy:

  1. Look for the obvious, burns, discoloration etc.
  2. Look for any electrolytic caps that seem "bloated"
  3. Test power resistors for open circuit (sometimes short circuit too)
  4. Test diodes
  5. test power semiconductors transistors/ mosfets
  6. Identify ICs and look online for the datasheet and the typical application circuit.

So far i was able to repair the power supplies that failed.
Be careful ! : There are capacitors still charged at √2*mains voltage after the mains supply is switched off.

Another source for help is the EEVblog forum under the repair section.