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Picture of How to make use of an old computer PSU
In this instructable, I will show you how I made good use of old PSU circuit boards and how you can do the same. 

You can find a more detailed version of this project on my website.

You can also see how to make your own computer desk fan here

And here for the Case/Safe PSU Combo itself

 
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Step 1: Things you'll need

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Here is a list of essentials:
  • solder iron (preferable one averaging around 50 watts)
  • a pair of helping hands
  • a flat head screwdriver
  • a Phillips screwdriver
  • cutting pliers (to cut the wires)
  • a solder sucker or solder wick
These are the optional extras I used:

Step 2: Make the circuit board safe to work with

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To be safe working with a circuit board that uses mains voltage, the reservoir capacitors must first be discharged. To prevent electric shock, do not touch the underside of the board (shiny soldered metal contact) when holding it. Hold the board by it's sides or something sturdy such as the heatsink.

The mains/reservoir capacitors are the two large cylinders shown above. Think of them as storage tanks of electricity or as the name implies, reservoirs.

To discharge them, use a screwdriver to short the two metal leads together for each capacitor. If you see a large spark, that means that the capacitor still had a large charge stored in it in the range of 110V -240V dependent on the input voltage and may have been lethal if ignored.

Disclaimer:
This is not to scare or discourage you but, handling the circuit board can be very dangerous if the mains/reservoir capacitor is not first discharged. High voltage may remain stored in the reservoir capacitor even after being unplugged for a few years. Always release any residual energy that may be left in the capacitors by shorting the two leads together. You could get seriously injured or die if mishandled. I am NOT responsible for any injuries you may receive for failing to adhere to proper safety procedures.

Step 3: Removing the wires

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Now that the board is safe to work with, the output DC wires can be removed from the board. To do this, use a cutting pliers to cut the wires as close to the board as possible. That way, the maximum length of the wires are saved and not wasted if they were cut say in the middle.

Step 4: Desoldering time

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Once the circuit board is held firmly, you can begin to desolder. Start with one corner of the board first then work your way over to the rest of the board.

Step 5: Making progress

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Be careful not to hold the solder iron too long on any lead as this will transfer too much heat to the components and may burn them out.

A good technique I found was to remove a little solder at a time then allow to cool slightly then go again rather than to apply full heat for a longer duration to remove the solder that will risk damage to the delicate components. This is especially true of transistors.

Step 6: Further progress

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To desolder the transformer leads efficiently, I found that heating the leads and while simultaneously sucking the molten solder away works best compared to heating, removing the iron then suck away.

Step 7: Finishing up

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The desoldering process continues until the entire board is desoldered. This is what the board looks like with all of the components desoldered.

Step 8: Sorting and Storing the Components

The nifty thing about the case/safe is that it has a lot of storage space in a wide range of disguised compartments.

I hope you found this project useful.

If you have any questions, please leave them below.

You can also take a look at my other projects below:

The Case/Safe PSU Combo

EFPU

Stand alone CD Player

CDROM Power Adapter

Portable Bug Zapper

How to dismantle a CRT monitor


SirCheez1 year ago
Newer PSUs usually have bleed resistors to prevent danger, but you should still be careful because many don't.
pfred22 years ago
Desoldering printed circuit boards with soldering irons is a waste of time. For heat sensitive components it can often be a waste of parts too. I've had this discussion enough on the Internet that I'm sick of it myself though. You should really find a better way to strip boards. How I do it is expensive and elaborate but I think it is worth it. The best way I've seen was in a video on YouTube of this Chinese guy who was working over a dished piece of sheet metal that had a puddle of molten solder on it. He was rocking! It was a very professional setup and it didn't look expensive to replicate at all to me.

Had I been exposed to that method before I invested in the equipment I have now I'd have likely gone that dished metal route myself. In any event putting the board into molten solder then plucking out parts is the best way to strip boards. Soldering irons are meant for other tasks.

Horses for courses.
MrJentis (author)  pfred22 years ago
Thanks for your insights. I do agree that desoldering with a soldering iron is time consuming and perhaps is not the best method. Feel free to share that youtube video here so others can learn too.
blkhawk2 years ago
Your method is called reverse engineering.