can I downscale a powersupply brick to power my HDD and enclosure?

[newtoCaps101]

Hey Guys, so I was wondering. as you already know my cheap Hard Drive enclosures power brick died recently. Since I actually have a few salvaged adapters and bricks in my house, a couple from old LCD monitors. I was wondering if I could maybe "downscale" or downgrade one of these power bricks to power my HDD enclosure?

They look quite well made and I still have my enclosures power brick so the plug / socket shouldnt be a issue if I can downscale it and hack them both somehow instead of forking out $30 for a new enclosure?

here's the specifications of my enclosures power brick

MODEL: CSE35-G
INPUT: 100-240VAC, 50/60Hz 0.5A
OUTPUT 12v === 1.5A
5V === 1.5A

new lcd power brick specifications
INPUT: 100 - 240V -- 1.0A MAX
50 - 60Hz, 100 - 200VA

OUTPUT 12V === 4.0a
OUTPUT POWER: 48W MAX

[tom66]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

In most cases it doesn't matter if the output current is higher.

Think of a sound system... it can provide maybe 40W output power, but would you use that all of the time?

There is one very rare exception and that is if your drive goes into standby a lot. Some power supplies don't like low load. However, you can check this with a multimeter. If it's okay with no load it will read within ~5% of 12V (11.4 - 12.6V.)

[joshnz]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

OUTPUT 12v === 1.5A
5V === 1.5A

OUTPUT 12V === 4.0a

You will need to make a 5 Volt supply to use the monitor power adapter.
Can be made from the 12 volt supply.

[mariushm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Most hard drives don't use a lot of power from 5v, they use that strictly for the electronics. So it's safe to say the average drive uses about 0.3-0.5A of power on 5v.

The 12v is important, the drives will use up to 1-1.5A of power on 12v.

Considering the load on the 5v is so small, you can generate the 5v by using a linear voltage regulator powered from the 12v line.
You can buy such linear regulator for 0.5-2$ pretty much anywhere.

For example the classic 7805 is on Digikey for as low as 0.66$ in a package easy to work with. It can do at least 1A of output, which should be more than enough for any hard drive.

http://search.digikey.com/us/en/prod...ETU-ND/1051218
http://search.digikey.com/us/en/prod...05CT-ND/458698

Both of the above have 3 pins :

input - at least about 6.5v or higher to get 5v out, you have 12v which is ok
ground
output - 5v

so you basically wire them like this

+ 12v ---- [  +  ] ----- IN 
      [ C1  ] 
- GND -----[  -  ] ----- GND --------- [ -  ]----------- - GND
                      [ C2  ]
              OUT --------- [ +  ]  -------- + 5v

where C1 and C2 are two capacitors. C1 should be rated for minimum 16v and C2 should be rated for minimum 6.3v.
The datasheets recommend at least 1uF on both sides, but I usually use 47uF or higher.

You will just have to be also careful because this chip will get hot so you need to screw it to some heatsink or an aluminum piece of something.
The difference between 12v and 5v gets converted to heat, so the heat output will be (12v - 5v ) x load ... so if the drive sucks 0.3 A the heat ouput will be 7v x 0.3 = 2.1 watts.

Without any heatsink connected to it, the chip can probably dissipate about 1-1.5 watts so you definitely need even a small heatsink. Something like this should be enough for the load of a single drive : http://search.digikey.com/scripts/Dk...000G&x=14&y=10

[Scenic]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

http://search.digikey.com/us/en/prod...43-5-ND/585964
^ 7805CV, which supports up to 1.5A load. Just in case.

[b700029]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Or you can use an "all-in-one" switcher IC like the LT1076-5 which requires very few external components, if you don't want to waste power on raising the temperature of a heatsink.

[newtoCaps101]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

thanks guys, but i might need a bit more help. i can actually see me doing it the way mariushm describes but then again these caps and chip will just be hanging on inside the power brick somehow? Is there any way I can fake or create the 5V without having to buy an IC chip? something i can salvage somewhere or bypass using something in the two power bricks? I am in NZ so getting things online or having a local electronics store is not always the best option.

Most hard drives don't use a lot of power from 5v, they use that strictly for the electronics. So it's safe to say the average drive uses about 0.3-0.5A of power on 5v.

The 12v is important, the drives will use up to 1-1.5A of power on 12v.

Considering the load on the 5v is so small, you can generate the 5v by using a linear voltage regulator powered from the 12v line.
You can buy such linear regulator for 0.5-2$ pretty much anywhere.

For example the classic 7805 is on Digikey for as low as 0.66$ in a package easy to work with. It can do at least 1A of output, which should be more than enough for any hard drive.

http://search.digikey.com/us/en/prod...ETU-ND/1051218
http://search.digikey.com/us/en/prod...05CT-ND/458698

Both of the above have 3 pins :

input - at least about 6.5v or higher to get 5v out, you have 12v which is ok
ground
output - 5v

so you basically wire them like this

+ 12v ---- [  +  ] ----- IN 
      [ C1  ] 
- GND -----[  -  ] ----- GND --------- [ -  ]----------- - GND
                      [ C2  ]
              OUT --------- [ +  ]  -------- + 5v

where C1 and C2 are two capacitors. C1 should be rated for minimum 16v and C2 should be rated for minimum 6.3v.
The datasheets recommend at least 1uF on both sides, but I usually use 47uF or higher.

You will just have to be also careful because this chip will get hot so you need to screw it to some heatsink or an aluminum piece of something.
The difference between 12v and 5v gets converted to heat, so the heat output will be (12v - 5v ) x load ... so if the drive sucks 0.3 A the heat ouput will be 7v x 0.3 = 2.1 watts.

Without any heatsink connected to it, the chip can probably dissipate about 1-1.5 watts so you definitely need even a small heatsink. Something like this should be enough for the load of a single drive : http://search.digikey.com/scripts/Dk...000G&x=14&y=10

many thanks for the wiring diagram, it helps a lot and i think have the caps at home but I am a bit confused about the C2 and the whole wiring the caps (C1 and C2) in general. I mean a cap only has two legs, but in the diagram it feels like it has 4! The Minus which is marked by the minus side and the plus side. On your diagram it shows the 12V connecting to the C1 caps plus side and then having an direct output to the connector, then the Minus side connecting to the caps minus and then on to C2 caps minus side and going straight to the connector, then we have the 5V that comes out of the plus side of the C2 cap. a bit confused

[newtoCaps101]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

and i should add its a Sata Hard Drive enclosure, if it helps

[budm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

May be you should read this.

[Scenic]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Could you post some pics of the HDD case itself with its circuit board?
Would probably be easier to just feed 12V to the case and have the 5V regulator inside the HDD case (if it's metal, it could act as a heatsink too)

Attached a (very) crude drawing of what mariushm meant. Getting 7805's shouldn't be a problem really. They're jellybean parts. Every electronics store should stock them.

edit: since when do .gif's automatically get converted to much smaller (in dimension) and shitty quality jpg's when you attach them? that's retarded..
Had to save it as a jpg and re-attach it so it doesn't get resized and unreadable

[budm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

HI Scenic, what do you use to make the drawing? It looks good!, Thanks!

[mariushm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Since you're in NZ, try Farnell aka element14 :

http://nz.element14.com/jsp/search/b...atchallpartial

^ link for the voltage regulator.

Should be a category for the heatsinks and that heatsink i linked to or something similar should be there.

As far as I know, Farnell/Element14 has free shipping to Australia, should be the same for New Zealand.

You can just solder wires to the pins of the chip and then use duct tape or heatshrink tubing to isolate it... drill/punch a hole in the adapter plastic then put the screw through the drilled hole and attach the heatsink and chip to the case of the adapter.

If there's room on the box, you can actually have everything inside this way, just a small part of the screw sticking out.

ps... In Scenic's version the negative side of each capacitor is at the bottom. I'm going to add a picture of the circuit myself in a moment just to be extra clear.

here you go:

[Scenic]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

HI Scenic, what do you use to make the drawing? It looks good!, Thanks!

MS Paint

I just googled for a generic TO-220 photo and pasted that in there. The rest are just fat lines and filled circles.

[budm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Thanks.

[ben7]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

If you have trouble getting an IC voltage regulato, you can use a resistor, zener diode, and a regular NPN transistor to make a voltage regulator.

-Ben

[joshnz]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

I am in NZ so getting things online or having a local electronics store is not always the best option.

Great source of components here in nz free shipping
http://newzealand.rs-online.com/web/

[newtoCaps101]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Hey Guys, I couldn't find the LT10765 but I got a 7805CV and ordered it (thats the one right?), should be in the mail in the next couple of days

I also got some 16v and 6v caps at home, I salvaged from some old motherboards, they are 1500 uF however. Well anyway, I will be back in a couple of days when I get the chip and hopefully we can make the power supply work with my enclosure.

Will also post some pictures of both adapters and the enclosure soon.

[mariushm]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Those 1500uF will work.

In some extreme cases, with some very sensible hard drives, you may have to plug in the power supply and leave it to charge the capacitors first for about half a second before you plug the connector in the hard drive.

7805cv is OK. This one is linear regulator, for which you only need those 2 capacitors.

For LT1076-5 you would have needed at least a Shottky diode and an inductor which are a bit harder to find locally. The advantage would be that this chip doesn't get so hot as the 7805 ones.

[newtoCaps101]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Okay Guys, I got the parts
I will post pictures of the adapters in the next post..

[newtoCaps101]

Re: can I downscale a powersupply brick to power my HDD and enclosure?

Pictures of my old (original power supply brick of the enclosure) I have noticed a 16V and a 10V cap and some resistors on the PCB that creates the 5V line.