Author Topic: Use PC powersupply for CPC?  (Read 1177 times)

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Offline FruityFrank

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Use PC powersupply for CPC?
« on: 20:49, 02 December 19 »
Hello,


in order to reduce cable-mess I thought about getting rid of all the small powersupplies and replace them with one fat PCU.


There are these nice breakout boards available:





You think its a good idea? or may characteristics of a switching PSU even harm the old hardware?


Thanks,
 Frank

Offline Bryce

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Re: Use PC powersupply for CPC?
« Reply #1 on: 10:51, 03 December 19 »
That should be fine as long as you make sure to use the correct fuses (ie: around 3A on the 5V rail and 500mA on the 12V rail). Otherwise, if something goes wrong you'll completely destroy the CPC.

Bryce.

Offline GUNHED

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Re: Use PC powersupply for CPC?
« Reply #2 on: 21:21, 03 December 19 »
0,5 A for 12 V? Isn't that a bit too small? Measure peak usage of 3" floppy (spin up).
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Offline Bryce

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Re: Use PC powersupply for CPC?
« Reply #3 on: 09:16, 04 December 19 »
The 12V rail peaks at about 270mA even on an old worn out drive.

Bryce.

Offline geebus

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Re: Use PC powersupply for CPC?
« Reply #4 on: 11:01, 04 December 19 »
Waw, that's pretty low for a floppy drive. I done a bit of research into it when I was making my external 3.5" floppy drive and seen that they were around 700mA peak.
You've made me think that i should possibly fire in an in line fuse though as it's currently being powered via a 2A USB charger.

Offline Bryce

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Re: Use PC powersupply for CPC?
« Reply #5 on: 11:17, 04 December 19 »
A 3.5in drive is completely different. It's running completely on 5V. A 3in drive has 5V for the electronics and 12V just for the motors. I tested around 15 3in drives when I was developing my 5VCPC interface and I never found a drive above 300mA.

Looking at that in Watts:

3.5in Drive: 5V x 0.7A  = 3.5W
3in Drive: 12V x 0.27A = 3.24W (plus whatever the electronics needs from the 5V rail)
That makes them pretty similar.

Bryce.

Offline geebus

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Re: Use PC powersupply for CPC?
« Reply #6 on: 12:02, 04 December 19 »
Ah! the power of Math!
yeah, that makes sense now.