do my idea work? building power for my harddisk

[cpteoh26]

hi all. i have a USB-SATA converter. but unfortunately the power supply died yesterday.
anyway, i am thinking, is it possible i create my own power supply for my harddisk.

i take the 230Vac, step down to 20Vac and rectifier and filter with capacitor.
from there, i should have 20Vdc.
i then connect them to 7812 and 7805 voltage regulator chip, to get 12Vdc and 5Vdc supply respectively.
finally i just connect them to molex to SATA supply cable.
well, i can do all these for below USD$5. shop selling the power supply adaptor for USD$15. therefore, i actually save USD$10, and it is my insterest do DIY electronic work.

anyway, is my idea above work, and safe to use? well, definitely, i don't want to burn my harddisk down.
or, is it safer and more secure to just buy a new power adaptor at USD$15?
hope sifu and pro here could advise me please.

thanks.

 

[pranam77]

I would suggest you to buy a new power supply. Coz the 7805 and the 7812's will deliver a max of 800Ma current in practical, that too with good heat sinks mounted. You may boost the current with a high current regulator circuit as mentioned in the device datasheets. Naturally the drive may sink more than an amphere of current during some phases of its operation which may prove fatal to the 78's or the drives. Cheers

 

[cpteoh26]

hi
well, i have another idea on build power supply..
i have one laptop charger, which supply 18Vdc 4.8A..
well, could i use diod to step down the voltage to somewhere near to 5Vdc and 12Vdc and use it??

please guide me.
thanks.