How To Repair Atx Power Supply Diagram

In this document, I bear witness yous a repair article with loftier voltage sources.If you are not familiar with high voltage and or you lot have not the right tools, please do non repair this type of units.High voltage can damage your wellness even finish in death.

Today a call comes downward on my phone line from an accounting agency with a serious problem on their server PC where the databases of the customers are stored. The PC could not start and the other client computers could not work in the function because of no server problem. I moved immediately to the agency to see what is the problem and what is to practise.

The server is a PC P4 with XP and with an MS SQL server installed on. Not a large deal but information technology does the job. In a few second I got the ride with the trouble of the PSU, figured out does the PSU is bad. The agency has no other PSU for state of affairs like this so I have to order one. However, it volition take a mean solar day or and so earlier information technology arrive. I decide to repair the PSU.

Outset, I checked for the version number of the PSU. This PSU is a Version 2.three as y'all can see on the photo right in the table of DC OUTPUT MAX. These version numbers draw the typical construction of the PSU, which is an international regulation, and must fit the mechanical and electrical standards.

Here is a revision history of the PSU versions:

Version Release Date Notes

1.0 Dec, 1997 Public release

1.one Apr, 1998

• Updated all mechanical outlines to clean up dimensioning of mounting holes.
• Added chassis cutouts for all mechanical outlines to clarify continue-out areas.
• Added Appendix C. 2.0 May, 2001
• Added SFX12V clarification
• Additional power ratings added
• Updated manufacture standards
• Increased standby current

2.1 Aug, 2001

• Section 4.4 Updated Figure iv SFX/SFX12V Connectors
• Section 5.eight removed vendor name 2.2 Dec, 2001
• Section 3.23 Typical Power Distribution. Change minimum loading on 5V rail to 0.3A
• Section 3.three.2 PS_ON#. Add together text "The power supply should not latch into a shutdown

country when PS_ON# is driven active by pulses between 10ms to 100ms during the decay of the power rails."

two.3 April, 2003

• Reformat and update revision table
• Update Disclaimers
• Remove guidelines for SFX without 12V connector
• Updated power and current guidance
• Added efficiency targets for calorie-free and typical loading
• Increased minimum Efficiency at total load from 68% to 70%
• Updated guidance for standby efficiency
• Added Series ATA connector
• Updated cross regulation graphs

This is ver.2.3 PSU, there are no big differences what the electronic stuff means.

My second and very minimalistic exam was to disconnect the PSU from the motherboard and from all other devices, shorted the GREEN and Black wire wit a wire. The PSU started up immediately.

I was a bit surprised! I expected does the PSU will non power up, simply…

After this exam, I connected my Xilence PSU tester to the unit of measurement and see what is happening:

In real world, this blazon of testing is nix than checking the voltages and the PG fourth dimension. This type of tester are failed in lot of state of affairs and practise not detected a bad PSU even when a load is added on the PSU or without that. In other words, it is just a multi meter which can evidence all the voltages and the PG time on one screen on the aforementioned fourth dimension. Do not expect too much from this tool.

Tin can yous recognize the problem? Yeah? ok, No? no problem. Bank check the zoomed picture of my tester. You tin can run across four different voltages and one so chosen PG in ms.

Voltage i: +3.3V

Voltage two: +5V

Voltage 3: +12V

Voltage iv: -12V

The PG is the Power Good signal, which is measured in milliseconds or ms.Every PSU take a DC Voltage regulation, which shall remain within the regulation range. With or, without loads on the output connectors.

This is the DC output Voltage tolerance.

Here I made for yous a DC output tolerance tabular array, which y'all tin can use for almost every ATX PSU for PC computers. In nearly case, I utilize the reference guide made past Intel.

I got a measurement on my PSU tester on the 5VSB between iii.9v – 4.5v. This is outside of the tolerance table and makes the mistake.+5 VSB is a standby supply output that is active whenever the AC power is nowadays.

This output provides a power source for circuits that must remain operational when the five master DC output rails are in a disabled state. Example uses include soft power control, Wake on LAN, wake-on-modem, intrusion detection, or suspend country activities.

Today's modernistic motherboard has a then-called logic controlled power up circuit. Therefore, the power push button is connected to the motherboard and not to the PSU every bit it was on the sometime type of PC-southward. Considering of this logic control circuit the PC can't power on merely without the mobo the PSU powered on when I shorted the green and the black wire on the PSU connector which goes to the motherboard. The next very of import element to problem shooting is the PG parameter.

The Power Good or by Intel PWR_OK is a signal used by the organization power supply to signal that the +5VDC, +3.3 VDC and +12VDC outputs are inside the regulation thresholds of the power supply. If the PG signal timing is between 100ms and 500ms the PSU should be fine otherwise the PSU have some problems. Equally I realized does the 5VBS are in a bad range, the PG signal is in range with the other voltages I was sure does there is not a big problem. Lets see what was the problem:

Inside of the PSU. A bit dirty simply naught unusually or? I recognized a slightly swelled capacitor. I took my good old ESR meter, which is a homemade i and checked all the caps and this one too. After the checking of the caps, there was only one cap out of the range. This bulged 1.

Here is the reading, LOŠ means BAD.

After this, I checked for shortened components or faulty 1 just null else was found. In that location was another small problem. A grinding dissonance, come out from the cooling fan unit of the PSU. Later on I disassembled the fan, and add some graphite grease, the grinding noise was gone. See the pictures below.

Cleaned the whole unit with compressed air and assembled information technology together. Hither is the result:

Afterwards I put the PSU back to the server, it powered on and worked well.

You can find dandy ATX PSU repair guide from Mr. Jestine Yong on this web site: http://www.powersupplyrepairguide.com if you interested to larn how to repair these kind of equipments.

Decision:

I utilise this technique to quickly identify the place or path of the problems in these kinds of units.

– short the greenish and any black wires on the connector when the PSU is out of the PC

– if PSU starts than y'all have no big problem

– if y'all have a PSU tester something like mine utilize them to measure the voltages and PG, if

non then utilize a usually multi meter

– cheque the results with the voltages output reference table from this article

– identify the faulty voltage and start checking the parts in that area

This commodity is for bones skilled repairer and novices in the earth of PSU repairing.

For further learning of the technique of repairing PSU equipments delight refer to the books by Mr. Jestine Yong who fabricated a well explained repairing guides with great pictures and explanations.

I promise you will enjoy this article.

This article was prepared for yous by Christian Robert Adzic from Novi Knezevac-Serbia.

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