Needing Step By Step Instructions for Dismantling Thermaltake Purepower Power Supply

Hi Everyone;

        For purposes of troubleshooting a random power down problem of my main pc, I am needing step by step instructions for dismantling the following power supply:  Thermaltake Purepower (Model:  HPC-420-102-DF).  Basically, I am interested in getting inside of this power supply in order to get a visual inspection of the capacitors.  I have been told from a currently open post the capacitors within the power supply should be flat on top and not bulging out or leaking.  

          Any suggestions or resourceful links outlining the proper protocol for dismantling this power supply will greatly be appreciated.  

          I will look forward to hearing from everyone.  And, many thanks in advance for any help on this one.

          Thank you

          George
GMartinAsked:
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Jeremy MIT SpecialistCommented:
I am not sure what kind of guide you are looking for but a power supply is pretty basic.  They have a cover that you remove and it is usually like eight screws.  Once that cover is removed, you can visually see the guts of the power supply.  It is true, a capacitor should be flat on the end of the cylinder and should not have anything leaking from it.  When you do get the power supply opened up, alos look for discoloration on the circuit board that might identify burn marks around the post of any components.

Here is a link to a picture of your PSU opened up.

http://www.xbitlabs.com/articles/other/display/thermaltake-psu-roundup_3.html
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
GMartinAuthor Commented:
Hi There;

        Thank you so much for the information and the resourceful link.  I do have some followup information to provide to this post.  While the tops of the capacitors within the power supply looked normal with no visible evidence of top bulging, there was a tiny pink, skinny shaped cylinder on the circuit board which appeared to have some brownish discoloration at the base.  I interpreted this to be either corrosion build up or burn mark because the other two which looked like it did not have any discoloration at the base.  I am not sure what these little components are technically called, but, they were soldered onto the main circuit board like the capacitors.  

             While the hookup to the ATX Power Supply Tester indicated the power supply to be in good condition, I still think it is defective.  What would you suggest at this point?  

              Thank you

              George
0
PCBONEZCommented:
Hi George,
If the discoloration is a darkening of the printed circuit board (PCB) that indicates something is getting too hot.
If it's more like a residue it is probably soldering flux left over from manufacturing it. (A little sloppy but not particualarly unusual on mass produced items.)

I think this may help some:
http://www.hardwaresecrets.com/article/327/3
Anatomy of Switching Power Supplies
Author: Gabriel Torres ,,, Type: Tutorials  

This review is not your exact model but he goes all the way to PCB level and that may help you familiarize.
http://www.hardwaresecrets.com/article/332

Also if you are going to go as far as replacing parts the forums at badcaps.net have several members that rebuild power supplies on a daily basis.

From the glimps of the PCB in link in the earlier post I can tell you that the unit isn't top of the line but is certain isn't a low end either. It has an input filter (cheap ones don't) and the tranfromer is a decient size (cheap units have small ones). It's a little light on the cap count on the output filters but if they are quality caps that shouldn't matter very much.
As long as it's in good shape that should be a decient power supply.

.
0
Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

nobusCommented:
George, you can attach  a picture if you like...
0
GMartinAuthor Commented:
Hi Everyone;

        Thanks so much for the followups.  If possible, could someone supply a link to upload a picture?  I will go ahead and try to zoom in on the area I found questionable.

         Thank you so much.

         George
0
PCBONEZCommented:
There should be an 'attach file' below the edit box you write in.
If you check it a place to load the file will appear.
0
GMartinAuthor Commented:
Hi There;

         Thanks so much for the advice.  Please find attached a picture of the internal power supply.  The area I question is located about at the center of the picture.  It is a pink colored, cyclinder shaped tiny component on the motherboard.  It appears to have some discoloration at the base which seems similiar to either a burn mark or residue built up.

          Thanks

          George
MVC-002S.JPG
0
PCBONEZCommented:
That is a resister.
I can't see the discoloration in enough detail to tell for sure but it does look like it may be a heat issue.

Do you see that black IC chip on the heat sink with the screw. The resistor is leaning on it. Those get extremly hot and the resistor touching it may be the problem. It is okay to simply bend the resistor (or rather it's wires) away so there is at least an 1/8" air gap. A little more gap would be better.
-
If you can't reach it with your finger then grab the resistor's lead on the end closest to you with a needle nose plier or hook it with the end of a screw driver (or a dental pick) and pull/push it away a little bit.
Don't use the IC chip for leverage.
They aren't as hard as they look and the IC chip's case may crack that way.

.
0
PCBONEZCommented:
Another thing you might want to do is remove the PCB and see what is going on on the other side.
It should just be 4 screws and some manipulation to work it out.
(You may have to remove the fan for clearance.)
* No need to cut any wires for this.
Some have a sheet of plastic for an insulator between the PCB and the 'box'.
If it does then pay attention to the orientation so you can replace it the same way.
0
PCBONEZCommented:
What I am thinking is maybe the resistor has a bad solder connection and that's where the heat is.
0
GMartinAuthor Commented:
Hi There;

       Thanks so much for the followup.  Not to get off the topic too much, but, what function does the resistor carry out?

       George
0
GMartinAuthor Commented:
Hi

        I notice exactly what you mean.  The resistor is making contact with it.  I believe I can pull it away enough so air can circulate freely in that area.  By the way, if the resistor did overheat and cause the discoloration at the base, is it possible the power supply will still function acceptably once reassembled and installed?  Or, is this a situation in which a new power supply is in order?

         Thank you

         George
0
Jeremy MIT SpecialistCommented:
George,

to see if the resistor itself is damaged, you can use a multimeter, set to ohms.  check the color code of the resistor and compare it to the reading on the multimeter.  just touch the leads to the posts on either side of the resistor.  Use this site to help with the color code.

http://samengstrom.com/nxl/3660/4_band_resistor_color_code_page.en.html

0
GMartinAuthor Commented:
Hi

      Thank you so much for the link.  Will I need the power supply powered one when conducting the test of the resistor?

       George
0
Jeremy MIT SpecialistCommented:
No, resistance checks must be done with the power off.
0
GMartinAuthor Commented:
Hi

      Thanks so much for the information.  I do have two more followup questions to this thread.  First, what function does the resistor carry out?  Does it regulate the electrical resistance of the circuit board?  And, secondly, I do have a multimeter.  It is made by Velleman (Model DVM850BL).  With this in mind, I am wondering what would be the procedures for setting it to ohms?

         Thank you in advance for any further assistance given to this question.

        George
0
Jeremy MIT SpecialistCommented:
Plug your black lead into the COM port and your red lead into the right port (V"Ohms symbol"mA).  Turn the dial to the lower left green area of the meter.  The actual setting will be based on the resistance value of the resistor.  By flipping the dial to the different values in the green area, the decimal place will change.  Place your leads on either side of the resistor, doesn't matter which lead goes on which side.  You should see a readout on your multimeter.  

As far as the actual purpose for the resistor, I would not know without looking at the schematics for the power supply itself.  Not easy to come by.
0
PCBONEZCommented:
I just meant to check for a bad solder joint George.
It is called a "cold solder joint". - What happens is the solder 'sticks' to one side and not the other. (The two sides being the resister's lead and the PCB's solder pad.) When that happens over time oxidation will get in there or movement from heat-up cool-down will work a larger gap. It's possible to end up with a connection that is fine when it's cold but that is poor when it heats up.
(The bad connection causes a lot of localized heat in the joint.)

Note about resistance checks:
- The resistance measurement works by applying a small voltage (from the meter itself) and measuring how much current flows. If there are other flow paths the reading will be affected. But, if there is a parallel path the reading will always be low (never high) because more paths will always cause more current through the meter and not less.
- A low reading may be a bad (shorted) resistor or may be a parallel path.
- A high reading always indicates a bad (open or partially open) resistor.
If you get a low reading to be sure it is actually a problem you would have to  disconnect one end of the resister to break the parallel path in order get a good reading.

If you don't already know how to solder (and want to learn) you should acquire the equipment and some old circuit boards out of some junk gear and learn by taking the parts off and replacing them a few times.
Soldering takes practice but it's not really rocket science.
It does get harder as things get smaller. (From 'easy' to 'don't even try'.)
A PSU is on the easier side.
[Let me know if you want to learn.]

~~~

A resistor resists the flow of electricity which causes the voltage on one side to be higher than on the other.
The difference is called the 'voltage drop' across the resistor.
It is used different ways.
- To limit (slow down) current flow.
- To create a new voltage the circuit needs.
- As a load. A device to burn off excess energy. (Turns it into heat.)

Examples of creating new voltages [ wwwww will be a resistor here]

[two resistors, same size]
{12v} --------wwwwww----- {6v} -----wwwwww------------ {ground}
[each drops 6v]

[two resistors, right one is twice the resistance of the other]
{12v} --------wwwwww----- {8v} -----wwwwww------------ {ground}
[left resister is smaller dropping 4v, right is dropping 8v]

[two resistors, left one is twice the resistance of the other]
{12v} --------wwwwww----- {4v} -----wwwwww------------ {ground}
[left resister is larger and drops 8v, right drops 4v]

This sort of circuit is called a voltage divider.
[A voltage divider may have dozens of resisters and voltages.]
It's most common use is to set the static voltages at pins of other components to some point in their operating range.
If 4v at pin 1 makes the device stay off and we want it's normal condition to be off then we set the static voltage to 4v at pin 1 with a voltage divider.
(This is called biasing or to bias.)
If we want it to turn on we use another circuit to change the voltage at pin 1.

In your PSU:
That resistor is probably biasing the IC near it. (Just a guess....)

.
0
GMartinAuthor Commented:
Hi Everyone;

            First and foremost, I want to thank each person for their assistance to this complicated question.  Using the guidance given within this post, not only was I able to successfully figure out how to dismantle the ATX power supply, I was also able to troubleshoot the random power down problems.  Apparently, the resistor being bent and leaning on the heat sink caused it to over heat.  Using a pair of needle nose pliers, I was able to straighten the resistor to allow enough space between the internal components for air circulation.  

              Just to make sure the random power down situation was indeed fixed by straightening the resistor so it was not making any contact with other components, I ran MemTest on the computer all night for 8 1/2 hours as a burn in test.  When I woke up the next morning, I noticed the pc was still powered on.  So, it appears the resistor was overheating.  

              In addition to correcting the problem with the resistor, I also removed the heat sink from the top of the processor and used some compressed air to clear out dust and buildup.  Also, I removed all of the dried up thermal compound from the top of the processor and applied a new fine thin coat of it just for good measures.  

             In closing, I believe everything is going to be alright.  If there was still a problem, I believe the pc would had already begun randomly shutting down again.  So, maybe it is fixed this time and there will not be a need to replace the power supply.

            Many thanks again everyone for a great job on this question!!!  I certainly learned a great deal from each person's input.

             George
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Components

From novice to tech pro — start learning today.