External SF314 power supply replacement

General discussions or ideas about hardware.
User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

External SF314 power supply replacement

Post by sandord » Fri Aug 31, 2018 3:28 pm

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!

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Fri Aug 31, 2018 3:32 pm

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

User avatar
exxos
Site Admin
Site Admin
Posts: 12270
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: External SF314 power supply replacement

Post by exxos » Fri Aug 31, 2018 4:15 pm

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.
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.

poobah
Posts: 13
Joined: Fri Feb 02, 2018 8:44 pm

Re: External SF314 power supply replacement

Post by poobah » Fri Aug 31, 2018 8:38 pm

exxos wrote:
Fri Aug 31, 2018 4:15 pm
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).

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Fri Aug 31, 2018 10:36 pm

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.

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Sat Sep 01, 2018 1:13 am

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.

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Sat Sep 01, 2018 11:48 am

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.

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Sat Sep 01, 2018 1:46 pm

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
Untitled.png (137.14 KiB) Viewed 1910 times

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Sun Sep 02, 2018 2:08 pm

Here's the finished thing.

1.jpg
1.jpg (158.16 KiB) Viewed 1870 times
2.jpg
2.jpg (255.66 KiB) Viewed 1870 times

User avatar
sandord
Trusted Guru
Trusted Guru
Posts: 646
Joined: Mon Aug 13, 2018 10:08 pm
Location: The Netherlands
Contact:

Re: External SF314 power supply replacement

Post by sandord » Sun Sep 02, 2018 3:13 pm

3.jpg
3.jpg (317.84 KiB) Viewed 1867 times

Post Reply

Return to “HARDWARE DISCUSSIONS”