External SF314 power supply replacement

[sandord]

I've got this nice SF314 drive from a friend lately but it's missing its power supply.

This is what I read about the SF314 power supply:

Specifications

+12V ±5%:
60 mA (rest normal)
300 mA (read/write;normal)
850 mA (Maximal)

+5V ±5%:
340 mA (rest mode; normal)
380 mA (read/write; normal)
500 mA (Maximal)

From http://www.atari-forum.com/viewtopic.php?t=20337

I bought a 5-pin DIN female connector and I'm thinking of connecting it to this 12V adapter I have laying around. I also have a small buck converters which I can use to make the 5V level. I guess that in the most extreme case I'd need 850+500=1350 ma, which is way below my 12V adapters' limit of 2A, which should cover for efficiency loss of the buck converters, right?

Perhaps I should use another buck converter to stabilize the 12V line as well?

I'm not completely sure I'm on the right track here so perhaps someone can give me some advice? Thanks!

[sandord]

By the way, my buck converters got a LM2596-5 on them, which supposedly can handle up to 3A.

[exxos]

Probably the normal way is to just use a regulated 12V power supply, and use a internal 5V regulator..

I don't know much about external drives, but you may not even need 12V.. Only the really old drives generally need that voltage... I've always run my external drives just from a normal 5V brick PSU.

[poobah]

Probably the normal way is to just use a regulated 12V power supply, and use a internal 5V regulator..

I don't know much about external drives, but you may not even need 12V.. Only the really old drives generally need that voltage... I've always run my external drives just from a normal 5V brick PSU.

That's the route I would go (5v only).

[sandord]

Okay, tomorrow I'll try it with just a regulated 5V signal, leaving the 12V pin disconnected inside the plug. The 12V line is connected to the diskdrive inside the casing though but that probably doesn't say anything about whether it is used or not in the diskdrive itself.

[sandord]

Couldn't resist trying before going to bed. Sadly, it didn't work, the drive didn't show any life signs.

I will go down the 12V+5V route tomorrow. Let's hope the drive spins up, there's the chance it's broken of course.

[sandord]

I connected a spare ST psu to the SF314 and it works like a charm!

So, apparently there are some external drives that do need 12V.

By the way, I see a lot of misunderstanding about the SF314. Many people seem to think it is the single-sided version of the 354 but actually it is the other way around.

[sandord]

I thought I'd design myself a little 3D-printable box to provide a conversion between this 12V power adapter and the SF314.

Untitled.png

[sandord]

Here's the finished thing.

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[sandord]

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