Make a bench power supply mostly from recycled parts

This instructable will show you how to make a very good bench power supply using mainly recycled parts. This is the really the "mark II",  you can see "mark I" here. 

  When I finished my first bench power supply I was really happy, and used it very often, almost every day, until one day it decided not to work anymore, :(  so... I realized I had to do it all over again, including the not that easy drilling on the metal of the ATX, etc. So this time I'm making a bench power supply that you can replace the ATX in no more than 2min.

  Last time I did not take any pictures of the process, so  I could only do a slideshow of the finished product, but this time I took lots of pictures, so I did this Instructable, which I hope you'll like.

  May you decide to go ahead and build your own?... I would like to take the opportunity to say that I will be more than happy to help you with any questions you have, and also I will love suggestions so I can improve either this instructable or the bench power supply itself.

  As the title shows, with this instructable I want to encourage people to recycle. There are lots of things around the house or even in the streets, that you can take components off, and use them later to make so many interesting things. I used as many recycled parts as I could for this project, and if you do the same, you could have a very powerful and COOL! bench power supply for almost nothing.

OK.. lets start with a view of what we will be making....

Step 1 Materials and tools

Here is a list of the materials and tools I used for this project. Some of them are optional, like the analogue panel meters, as you could use any multitester to check ether the voltage or amps.

  The same with tools, you may want to use a different tool, just go ahead, and also make any suggestions so we all can learn.

  Don't be scared of the quantity of materials, this project is not really difficult to make, trust me, if I've done it, anybody can.


MATERIALS:

1).- (1)Bread box.( Recycled, you could use any other enclosure that you can fit the ATX in with enough space)

2).-(3) Switches (2 single way switches recycled from old heaters, and a 2 double way switch recycled from an OHP)

3).-Cable connectors (Recycled from old amplifier, and from old TV)

4).-(1) ATX (Recycled from old computer)

5).-(3) PC Drive Molex to SATA Power Adapter (ebay £1.50, view)

6).-(1)  20-24 Pin ATX power adapter for Computer PSU (ebay £2.77, view)

7).-(1) USB connector (Optional, Recycled from old computer)

8).-(2) LED's (red, green) , (Recycled from old computer)

9).-(2) 5K Potentiometer (One Recycled, and the other one bought for £1.35, view)

10).-(2) Potentiometer knobs ( Recycled from old amplifier)

11).-(1) empty can of coke (Recycled)

12).-(1) 8cm computer fan (Recycled from bench power supply mark I)

13).-(1) Magnetic Catch (Bought  £1, view)

14).-(1) IEC cable (The cable that connects the computer to the power socket, Recycled)

15).-(1) IEC connector( Recycled from bench power supply mark I)

16).-Piece of trunking (Optional)

17).-Some cable ties.

18).-(1)Fridge magnet ("Stolen" from the fridge)

19).-Some wires. (Recycled from extension lead)

20).-(2) 8cm Fan grills (Recycled from old ATX)

21).-(2)  Screw eyes. 


ELECTRONICS:

1).-(1) LM350 Adjustable Voltage Regulator (ebay £0.50)

2).-(1) 560 Ohm Resistor (Recycled from old radio)

3).-(2) 1N4001 Diodes (Recycled from old radio)

4).-(1) 0.1 uf Capacitor (Recycled from old radio)

5).-(1)  10 uf Capacitor (Recycled from old radio)

6).-(1) Heat sink (Recycled from old radio)

7).-(1) 10W 10 Ohm Wirewound resistor (Maplin £0.48)

TOTAL COST = £7.60


If you want to use analogue meters like me, and you also want to make the continuity tester,  you will also need in addition to the previous list:

1).-(1) Voltage panel meter (Optional £6 ebay, view)

2).-(1) Amp panel meter (Optional,  £6 ebay, view)

3).-(1) 6V Mini Relay (Optional, £1.31, view)

4).- (2) 9v PP3 Battery box (£1.29 each, view)

5).-(1)  9v Buzzer (Optional, £1.99, view)

6).- (2) 9V PP3 Batteries 

7).-(1) 1N4001 Diodes (Recycled from old radio)

TOTAL COST = £16.59

GRAND TOTAL= £ 24.19

TOOLS:

1)-Drill

2)-Hot glue gun.

3)-Dremel (With a cutting disc and round sander)

4)-Hole saw ( about 7cm)

5)-Epoxy

6)-Sand paper

7)-Solder

8)-A Dymo (Optional, I don't have one, my wife did the labels for me at work, but you could print them and tape them)

note: In this list of materials I specified where I found some of the parts I've used. I'm not saying that you need to buy an OHP or a home heater to get the parts, but maybe you already have some of these things at home and they don't work any more, or you can find then on the street, or in garage sales or in markets like the one you see in the picture below. 

Comments

[yoyology]

I'm thinking of making something like this using a big cigar box I have in my shop.

I want to make one set of outputs dedicated to 12V, one to 5V, one switchable (using a multi-position rotary switch I've salvaged) and then one more variable.

What I'd like to do is put a switch after the multi-position switch that will toggle between a straight line to one set of outputs, and a line with an in-line potentiometer to the other. That way I can adjust the output precisely. (See the block diagram below).

I'm just using the pot to dial down the voltage, instead of your voltage regulator circuit. I've tested the pot already from a 15V 1A wall wart, and it seemed to do fine. Will there be problems doing this over time?

[newtonn2]

You can't use a potentiometer to drop down the voltage, it will burn with load. A Wirewound potentiometer will do a bit better but not good enuf. The best way to do it is with the power regulator.

Sorry I took some time to answer.

[yoyology]

That's okay. I suspected as much, but wanted to be sure before I proceed. I'll need to dig through my parts bins now to make the regulator circuit. :-)

I'll post pics once I have the whole thing together.

[amarquez]

OH NOOOO!  Another PC Power supply conversion article using power resistors...   :(

Here we go again...

In any PC power supply you MUST have some load to make it function properly...  say, the 12 V output usually stays below full 12 V unless there is SOME load.  That is the reason people converting ATX style power supplies put a load on the 5V branch. (Mine puts out only 11.85 V when there is no load on the 5 V output...)

NOW; using a power resistor IS NOT THE BEST WAY. period.

The 10 Ohm resistor draws a lot of current from the 5 V circuit, and PRODUCES A LOT OF HEAT !...

NOW, if you use an automotive taillight and turn signal bulb, and place it in a socket, you can place a nice three level load.  Using two small switches, you can wire each of the two filaments to the 5 V output, so that you can power one, the other, or both filaments together; so that you can put just enough load on the 5 V circuit, so as to make the 12 V output produce something more than 12 Volts, so that your battery charger, car stereo. HAM Radio (or anything that you decide to be fed by your ATX power supply) will work perfectly.  My Triton2 battery charger can now put out a full 6.5 amperes when recharging a common 12V car battery, a task  it wasn't designed to do, but it does easily!  It can work for hours and more hours at full load without a complaint.

The automotive bulb has MANY advantages, it doubles as an easily seen pilot light, it produces much less heat to the inside of the enclosure, since it is now fed by 5 V, it will last many many hours.  The glass bulb is gas filled at a low pressure, which becomes an excellent heat insulator that keeps the glowing lamp filament from overheating the inside of the ATX enclosure.  There is NO need to use any kind of heat sink.  I have converted several PC power supplies for my friends, and have put the socket and bulb inside the original ATX power supply enclosure, locating it between the inside heatsinks directly on the airstream of the fan, so that it never heats the power supply components.  When it is working, the bulb in my PC power supply stays hot to the touch, but WAY MUCH LESS HOT than a 10 Ohm resistor!

Forget about using 10 Ohm wire wound resistors, they overheat too much and can melt some wire insulation or the nylon ties used to hold them in place.  The automotive socket and a two bulb package costs less than two dollars or less!

Been there, done that!

Happy new year everybody.
amclaussen, Mexico City.

[hemmikarl]

Exactly what i was thinking about.
why have a 10W power resistor at 10 ohms that will just be producing heat and using alot more power than needed

[techxpert]

yes now i dont need to buy a power resistor from another shop thanks :) :) :) :)

[techxpert]

so all the connectors are only needed if you want the psu back :)

[kasatka6991]

hello newtonn2 im kasatka6991
been building cheapo's psu out of old atx for some time and ran across your design
in a word marvelous
my only need is that i want the amp output to run as high as my psu will put out
antec true 430 watt psu
dc output +5v @ 36Amps +12volts @20 amps +3.3 volts @ 28amps
this is the big deal for me as i test and rebuild car power amps
some of which draw 15 to 20 or more amps at peak levels
the old unit we had at the old shop i worked at had a variac adjustable voltage and amps outputs
...................................................................................
so to my question how can i create the same function usin you design if possible but get more amps instead of the 3 amps or so from the lm350 controler
any advice is desperatly need as i cant afford 700 buck for a comercial unit
thanks kasa

[pfred2]

Your supply came out looking really nice. I like the stylish rounded top and bottom. A breadbox I've have never thought of that!

[shadow1489]

Hey Newtonn2 , I am in the process of building the bench power supply from your information you posted but there seems to be a step missing that i cannot figure out, I got to step 8 and umm yea I'm stuck ,, any help would be appreciated

[Paulvinn]

Thanks for the great instructables! I just finished my bench power supply that is based on your instructable. Mine maxes out at twelve volts. I cant figure out why. Also i just order parts to build an lcd projector. It takes a month to ship parts from Hong Kong! Anyways thanks for the cool projects.

[harvey639]

Hi newtonn2 i am in the middle of making one and i followed the link to ebay for the meters the only problem is that I don't know how to connect them can u please send me a circut diragram  via my email that would be really helpful thanks.

[newtonn2]

 There is a schematic on the step 8. If you need more information contact me.

[mat_adl]

newtonn2 Excellent benchtop by far the bast on the web. I just bought or salvaged everything I need to make it except for the panel meters. Your links are no longer attached to the parts you bought. What precision collision mentioned sounded good using meters with shunts that doubled as the power source when used.

Do you know what would be best to purchase?

I would be very grateful for you help.

I will shop in meantime.

[newtonn2]

Hi there!

Sorry the kinks don't work any more. They are a bit old.

check this links...

http://www.ebay.com/itm/3-DC-5A-Blue-LCD-Digital-AMP-Panel-Meter-Ammeter-/250599164625?pt=LH_DefaultDomain_0&hash=item3a58dfcad1#ht_3369wt_918

http://www.ebay.com/itm/3-DC-20V-Blue-LCD-Digital-Volt-Panel-Meter-Voltmeter-/260571455891?pt=LH_DefaultDomain_0&hash=item3cab44e193

They need an external power supply, (9v) but don't worry to much about the consumption as mine still working with the first battery.

best regards

[mat_adl]

Ok thanks but also I might not use wood . The system would be more compact with meters that are powered from the psu.

Do you have any ideas?

If not Ill use your links so thanks again brother.

[tgtomm]

Rather than using batteries and switches and such for the panel meters, you can use some dc-dc modules with isolated outputs. This sounds complicated but it really isn't.

I have just done this and put together a detailed guide on doing it over on my wordpress blog here.

Hope you find it useful.

[precisioncollisions]

I thought about dc-dc modules with isolated output is the only way. Glad you point it out.. Check ebay and they(Hongkong suppliers) have digital ammeters and voltmeters that can be powered directly from the "measured" circuit..

[mat_adl]

Could you or Newton show a link please?

[gr8_viruz]

"I can use ether -12v or 0v (ground), the reason I've done this is because the -12v is not as powerful as the 0v output. So with setting 1) I can go from 1.2V to 23V but is limited to 2A, and with setting 2) I can go from 1.2v to 11V up to 3A"

Is there a way to get 3A for the first option?
that it can make max 24V and 3A output.

[scratchr]

I think you could wire two atx power supples in parallel with diodes!

[Positive07]

Never connect them in parallel it can be a mess cause it can generate an overload... for 24V u can connect them in series that is safer but is difficult :D

[newtonn2]

 
I don't really know if is possible from the 24v output really. If you need a really powerful 24v power supply I would suggest to make one with an AC transformer.

[ASG_8]

Great Instructable!! :)

Can the 2 5k potenciometers replaced by 1 potenciometer of 10k?

Or could I put a 5k potenciometer and then another one of 1K or even less to have a more precise control of voltage?

Thanks!

[asdasd123123]

Hi,
Thanks it is very good instructable and exaxt thing I needed.I used a cheap multimeter and switch it on with a relay. And I used two 5W 12V bulbs in 5V circuit instead of power resistor.  So here are my pics:

[newtonn2]

Thank you very much for sending the pictures. They are the first pictures I see of someone that did something similar to my instructable. The bulbs light the inside, that cool!

Well done mate!

[paradise97402]

Here are some photos of my finished voltage regulator with a printed and developed PCB and the finished board

[paradise97402]

That power supply is the same one I am currently using on my old power supply..it does fine, in my Newtonn2 Power supply I am going to put two PSU in the cabinet and also fix it with two regulators and also affix the second PSU with pre set resistors, I do alot with LED's so then that will give me a fast connect on the power I use the most, and give the addition of the Newtonn2 design as well..
Ohh, and I had a brass name tag made for it that states "Newtonn2" on it so you now have a bench top with the credit to you for the design out there..thanks again

[newtonn2]

That's cool I would love to see it once it's finish!

[paradise97402]

Newtonn2, Sorry for takign so long, but been busy lately. btu I started gettin gthings together in th ecase, I decided to take th eATX out of th ehousing and mount it to some aluminum rails..

[newtonn2]

That looks very good. Well done. Did you try your circuit already? does it works fine?

[paradise97402]

Newtonn, Yes, the circuit works great..I went ahead and ordered some new meters..after looking at your back lit..I am goign to change them to ones like yours, but I am going to build another circuit to run on the second power supply, so I am goign to have to change the front to hold the extra parts on it. but I am also goign to take and put two regulators onto one PCB and this time I am going to go ahead and put the design onto a clear sheet develop it onto a sensitised board. but I will send you a copy of that one as well.
but with all the fans it is like a cyclone in there so ther should be no problem with anythign getting warm in there.

[paradise97402]

Newtton2 here is the board layout for the power regulator, this is the layout and drill guide.
the thing im not sure about is the third lead on the 5K pot.

[Jimmy Proton]

I followed the schematic exactly and have done so many times and every time it only goes to 1.3V max. I think its the voltage regulator because when I switched the LM350 with a IRF9432 it went to 24V with the same pin configuration but when i put it under load it sends the voltage to zero (it decided not to work anymore so theres no reason to take pictures) and usually burns out my potentiometers, I've lost at least three pots because of overpower and I'm wondering why yours are fine. I was thinking about just buying more LM350's, do you have any advice before I potentially spend my money on something I don't need?

[newtonn2]

I'm so sorry. I hope my I did the schematic right. No one told me yet otherwise. Did you try to do the simple schematic? You can check this one http://www.instructables.com/id/How-to-Build-a-Bench-Top-Power-Supply/

I will double check the schematic later.

[Jimmy Proton]

So I would just use the schematic you sent me and use it in the bigger circuit and thanks.

[Jimmy Proton]

I tried the new schematic and I only got .7Vout so it must me the regulator, I may have damaged it when I soldered it because I remember it getting very hot when I soldered it.

[Jimmy Proton]

Can I use an LM320 instead of an LM350?

[moeakram]

Hey I'm trying to make your power supply and I got my hands on a recycled 500 watt atx and I was wondering how would that affect the design??

[paradise97402]

Ok, well as I go trough my order I noticed that the Capacitors I got were both Radial types..and the only ceramic I have is a .1uf 100v will that work?