Scratch Build Bench PSU V2

[GuardianStorm]

Bench Power Supply V2

At last, I have gotten round to making the second version of the bench power supply. The Original is still working, although it does make funny noises and the 12 line inst amazingly stable. But that’s what you get for using an old PSU...

For the second version, I decided to include power sockets on the front and on the back, which mean the fan would have to be relocated from the back, and as I like to be able to stack things on top of things, it couldn’t go on the roof. In the end I settled for putting it in the base, and putting feet on the unit to allow air to get to it.

I also decided to make the unit out of wood (for a change) and used scrap that was lying round to make it. All the wood used is American White Ash, which is the same as the Laptop Stand that I made a while ago. The Ash is all 16mm thick, with exception of the lid which is 21mm thick.

Enough waffle! Onto the (de)construction!

This confused me slightly; I took the 120mm fan out of the PSU, and discovered this:

A large sheet of plastic across one half...I’m sure they have their reasons...but I don’t want that on there!

The rest of the donor PSU (£15.00 from EZ Computers), which includes thermal control, and 120mm fan:


Here we have the two sides of the PSU, and the two batons to mound the base to them with:


The base itself is made from a 3mm thick sheet of MDF, and is completely hidden when the unit is finished, along with the 120 mm blow hole in the middle, made using the router attachment of the dremel:

Man, this stuff is sooo much easier to work with than acrylic! Not as pretty though...

The general idea of the construction:


Add some holes, and insert self tapping screws:


To tha back panel, I added a switch hole, and a plug socket:


And then drill eight large holes most of the way through the wood, and then eight small holes in the base of the first set:


What the rear of this setup looks like:


And with a standard phono connector inserted:


The same process about to be applied to the front of the unit:


The two finished ends, which still need their final sanding:


Next, I started the gluing process (the lid to the sides, and not the ends, as these need to be removable):


While that was drying I set to wiring 22 connectors up...which took a couple of hours.

Some of the connectors to be used:


Confusingly, Black = 12v, Red = 5v for this build (there were no Yellow connectors in stock):


All wired up, in parallel, with loopback:


A little explanation on loopback:
Say you have 4 devices, all drawing 10 Amps, with this configuration:

As you can see the last link has 40 Amps going through it...not good. A better method is this:

This spreads the load better, and for the last part, you can use a heavier gauge wire.

The feet I used for this case are some old computer case feet:


And two shots of the case post sanding/pre varnishing (the small holes on one side are the ventilation for the case):




It then received three coats of clear varnish, and was left to dry, and had all the gubbins fitted! It even worked!

So, Final Shots:







Thanks for reading, comments welcome (Maybe I'll get back to work on Dark Vortex now...)

[wbdog206]

looks really good,clean build.

[Cheapskate]

Nice ash! (sorry, it's bad pun season.) Where did you attach the mains ground? I'm working on an all-plexi PSU for the first time and I have an interest in how you set up the guts here. I don't want to cook myself.

[500mph]

Any temp recordings?
It looks great. Bit scared of the wood though.

[NZ_mod_man]

Nice work! Waaay nice than my benchy. What was the PSU originally? Brand, power rating? I used a 230W thats about 10 years old.

[EDIT] you could also put a single socket and a plug with alligator clips on the other end for the 3.3v line to test LED's straight out of the box!!!

Another neat touch would be to flush mount a couple of amp meters in the side so you can see what sort of loads you are putting on it. Maybe some classic analog ones to got with the classic wood styling?? [/EDIT]

[Xs1t0ry]

Sweet mod.

[mvagusta]

lol @ the factory fan shroud I don't mean to be a party pooper, but....
Your inlet looks adequate on a flat desk, but on soft carpet the inlet area is squashy & very dusty You probably won't be using it on carpet though.
Your outlet for the case is very restrictive! = hot case Add up the area of those little holes, and compare it to the "donut" of area for airflow on the 120mm fan. You need to drill alot more little holes, probably the entire rear cover, or have at least half the front & rear sides drilled for outlets.
You could have also had all four pairs of connectors in parrallel not series, that way each thin lead is only carrying 10a, and those wires & connectors aren't too crash hot for 10a each anyway they'd get warm at minimum... but maybe you probably won't be using anywhere near 10a out of this thing?

I would have gone over the edges with a router & used a walnut or redwood stain, but that's just me, it looks good - just needs more outlet holes

Are you gonna install some switched dummy loads?

[Jipa]

Those wires still look very thin to me... Though I'm not sure if RCA-connectors can handle 10 A either. It still looks very nice, I should do something like this to myself.

[GuardianStorm]

Originally Posted by wbdog206

looks really good,clean build.

Thanks

Originally Posted by Cheapskate

Nice ash! (sorry, it's bad pun season.) Where did you attach the mains ground? I'm working on an all-plexi PSU for the first time and I have an interest in how you set up the guts here. I don't want to cook myself.

As the entire case is insulated, i havent attached the grounding wires anywhere

Originally Posted by 500mph

Any temp recordings?
It looks great. Bit scared of the wood though.

No Temp Recordings yet, soon though

Originally Posted by Xs1t0ry

Sweet mod.

Thanks!

Originally Posted by NZ_mod_man

Nice work! Waaay nice than my benchy. What was the PSU originally? Brand, power rating? I used a 230W thats about 10 years old.

The PSU is a generic ("EZ-Cool") 400 Watt from EZ Computers

Originally Posted by NZ_mod_man

[EDIT] you could also put a single socket and a plug with alligator clips on the other end for the 3.3v line to test LED's straight out of the box!!!

Another neat touch would be to flush mount a couple of amp meters in the side so you can see what sort of loads you are putting on it. Maybe some classic analog ones to got with the classic wood styling?? [/EDIT]

. I have another PSU for that...this is for powering all the crap in my room that would normally use wall adapters.

Originally Posted by mvagusta

lol @ the factory fan shroud I don't mean to be a party pooper, but....
Your inlet looks adequate on a flat desk, but on soft carpet the inlet area is squashy & very dusty You probably won't be using it on carpet though.

Its not on the carpet, well only for photos

Originally Posted by mvagusta

Your outlet for the case is very restrictive! = hot case Add up the area of those little holes, and compare it to the "donut" of area for airflow on the 120mm fan. You need to drill alot more little holes, probably the entire rear cover, or have at least half the front & rear sides drilled for outlets.
You could have also had all four pairs of connectors in parrallel not series, that way each thin lead is only carrying 10a, and those wires & connectors aren't too crash hot for 10a each anyway they'd get warm at minimum... but maybe you probably won't be using anywhere near 10a out of this thing?

I would have gone over the edges with a router & used a walnut or redwood stain, but that's just me, it looks good - just needs more outlet holes

Nothing draws 10A thankfully...And i might cut the vent holes out into a square and add air filters over them.

Originally Posted by mvagusta

Are you gonna install some switched dummy loads?

Probably not, its powering quite a lot of stuff

Originally Posted by Jipa

Those wires still look very thin to me... Though I'm not sure if RCA-connectors can handle 10 A either. It still looks very nice, I should do something like this to myself.

Nothing draws 10A...most of the stuff is 500mA or maybe 1.5A (Audigy 2NX)

[Jipa]

Oh no worries then, I just saw the diagram demonstrating the loopback and it was 10 A in that.

[GuardianStorm]

I fixed the air vents tonight, using some of the mesh from a £2 waste paper basket i bought:


which has made the PSU a lot quieter

[nickhelton]

oh man. throwing a real nice dark stain on that bad boy would make it crazy sick

[GuardianStorm]

Hehe it would look good i admit...but im all about the light wood colour See here...

[nickhelton]

oh i do like that stand. good idea with the holes for the 'feet'. if only i had a laptop
i plan on building a new computer desk which i will stain dark cherry, then distress and stain black

[GuardianStorm]

sounds good to me

[badders]

Loopback - Like Mains ring circuits instead of radials.

Awesome Idea.

Looking good BTW!