How to convert an ATX psu to an Amiga one (NO DIAL UP HUGE IMAGES)

rave · 12 July 2007, 00:13

Mods: I'm not sure if this is posted in the correct forum?
Also, Now 56k friendly! (is anyone still on 56k?)

Ok,
So I did this project because I have just fitted a laptop CD-ROM drive to
my A1200 (well almost - haven't cut the case yet) and wanted a beefier
power supply.
Also if I ever get enough money together to buy an accelerator I will need it, And I can't be arsed to pay over the odds for an ancient Goliath!

***Disclaimer***

I accept no responsibility if you blow your Amiga up or electrocute yourself, Your parents or your goldfish etc etc.

A few things to know first.

The wires in the ATX PSU are coloured and rated as below.
Some PSU's may have less or more colours so always check with a voltmeter,
but generally this is how they are:

Red = +5V
Black = Ground (0V)
White = -5V (not used in this project)
Yellow = +12V
Blue = -12V
Orange = +3.3V (not used in this project)
Purple = +5V standby (not used in this project)
Grey = Power is on (output) (not used in this project)
Green = Turn DC on (input)

ATX PSU's also have sense wires to detect current on the red and the orange
cables, some have more but they are easily recognised, when you look at the
motherboard connector you see the sense cable piggy-backed into the
corresponding coloured cable.

Generally the brown cable is joined to the orange and the pink goes to the
red, you need to connect these otherwise the PSU will not switch on.
I have included a pic to show you.

You will need:
==========

Tools:

A soldering iron, some heat shrink tubing or insulation tape,
cutters, screwdriver.

Components:

A 10watt 10Ohm wirewound resistor.
An SPST switch (single pole single throw).
An old amiga power supply.
And some patience!

1: Get yourselt an ATX PSU and open it up.....

2: Cut all those PC power cables out, but leave the motherboard connector cables long, these will be your Amiga connectors.
Join all the correspondong coloured cables together, including the sense wires I mentioned above:

You will need to leave long:

3 Black - 2 Red - 1 Yellow -1 Blue - 1 Green
Keep back a bit of cable to make an earth connection.

We don't use the purple and the grey, if you have them. just clip them back and heat shrink or insulation tape them.
Here are the sense wires connected together, this is very important or the thing wont start!

Connect a red and a black to either end of your resistor and attach it to the inside of the case, this will allow it to keep cool.
(also you can put some thermal transfer compound between the case and the resistor if you want to help dissipate heat better).
Why the resistor you ask? Well ATX power supplies are know as switched mode, and need a load to keep them switched on, this resistor basically couples it to a load state and forces it on.

Connect a green and a black to your switch (you could actually use the one from the doner miggy psu if you wanted)

Ok, on the cable from the amiga psu you have:

Yellow-Black-Red-Brown-White

These need to connect to the following colours on the ATX PSU.

Amiga White goes to ATX Blue
Amiga Brown goes to ATX Yellow
Amiga Red goes to ATX Red
Amiga Black goes to ATX Black
Amiga yellow goes to earth, you can solder it directly to the mains earth as I have.

Tidy up all your cables and fit your switch:

Hey presto, a decent, powerful and stable PSU for your Amiga 5/6/1200.

Kudos goes to Zetr0 for his pinouts on the amiga psu.

Hope this tut helps some people out.

Zetr0 · 12 July 2007, 01:40

@rave

thanks for the kudos

its a good pictorial, infact the largest i have ever seen (and i have a widescreen lol) great job rave!

(i have also sent your finger prints off to the FBI LMAO!!!!)

well done sir, a job to be proud of !

eLowar · 12 July 2007, 02:24

No offense, but how about changing this to thumbnails with links to the actual pictures? This thread is 20 MB (yes MegaBytes) in size. A nightmare for dial-up users, plus the huge images make my browser run sluggish (okay, it's a slight overstatement, the scrolling is just not as smooth as usual) and my computer is not particularly slow and has plenty of RAM (this makes Firefox take up like 300 MB by the way).

Edit: Good job with the thumbnails.

By the way, sorry about jumping at you with criticism, I'd like to point out that I think you did a very good job, I just didn't think the huge inline-images were a good idea.

I'm a little confused about the hot-linking issues. Where were the original big inline-images hosted?

T_hairy_bootson · 12 July 2007, 02:49

24 inch widescreen at work running at 1920 x 1200 and I still cant see the whole photo when viewing the thread, nice detailed mod by the way, I have only ever used an ATU PSU as it was kinda easier with the switch already.

musashi5150 · 12 July 2007, 09:13

I fitten an ATX supply into my A2000 a couple of months ago when the original one blew up. Followed the guide here:

http://www.ianstedman.co.uk/Amiga/am..._supplies.html

And it works great. Gutted the new supply to fit inside the old A2000 PSU case - you'd never know

Graham Humphrey · 12 July 2007, 11:11

Quote:

Originally Posted by eLowar

No offense, but how about changing this to thumbnails with links to the actual pictures? This thread is 20 MB (yes MegaBytes) in size. A nightmare for dial-up users, plus the huge images make my browser run sluggish (okay, it's a slight overstatement, the scrolling is just not as smooth as usual) and my computer is not particularly slow and has plenty of RAM (this makes Firefox take up like 300 MB by the way).

I agree, it took a while for this thread to load up here (on broadband as well); also this should really be in the prb.Hardware pics section I guess

rave · 12 July 2007, 15:45

@ eLowar,

No worries mate

The images were hosted on my own ISP webspace, I guess they stopped hot-linking?

eLowar · 12 July 2007, 15:53

Quote:

Originally Posted by rave

The images were hosted on my own ISP webspace, I guess they stopped hot-linking?

So you didn't move them? Because the inline images worked, but the links didn't work for me. Very odd.

Well I see you replaced them with smaller versions on a free host, that's probably for the best.

They look sharper like that too and as far as I can see you can still make out enough detail.

12 July 2007, 00:13	#1
rave Amiga's made me who I am. Join Date: Feb 2007 Location: Nottingham UK Age: 45 Posts: 178	How to convert an ATX psu to an Amiga one :) Mods: I'm not sure if this is posted in the correct forum? Also, Now 56k friendly! (is anyone still on 56k?) Ok, So I did this project because I have just fitted a laptop CD-ROM drive to my A1200 (well almost - haven't cut the case yet) and wanted a beefier power supply. Also if I ever get enough money together to buy an accelerator I will need it, And I can't be arsed to pay over the odds for an ancient Goliath! *Disclaimer* I accept no responsibility if you blow your Amiga up or electrocute yourself, Your parents or your goldfish etc etc. A few things to know first. The wires in the ATX PSU are coloured and rated as below. Some PSU's may have less or more colours so always check with a voltmeter, but generally this is how they are: Red = +5V Black = Ground (0V) White = -5V (not used in this project) Yellow = +12V Blue = -12V Orange = +3.3V (not used in this project) Purple = +5V standby (not used in this project) Grey = Power is on (output) (not used in this project) Green = Turn DC on (input) ATX PSU's also have sense wires to detect current on the red and the orange cables, some have more but they are easily recognised, when you look at the motherboard connector you see the sense cable piggy-backed into the corresponding coloured cable. Generally the brown cable is joined to the orange and the pink goes to the red, you need to connect these otherwise the PSU will not switch on. I have included a pic to show you. You will need: ========== Tools: A soldering iron, some heat shrink tubing or insulation tape, cutters, screwdriver. Components: A 10watt 10Ohm wirewound resistor. An SPST switch (single pole single throw). An old amiga power supply. And some patience! 1: Get yourselt an ATX PSU and open it up..... 2: Cut all those PC power cables out, but leave the motherboard connector cables long, these will be your Amiga connectors. Join all the correspondong coloured cables together, including the sense wires I mentioned above: You will need to leave long: 3 Black - 2 Red - 1 Yellow -1 Blue - 1 Green Keep back a bit of cable to make an earth connection. We don't use the purple and the grey, if you have them. just clip them back and heat shrink or insulation tape them. Here are the sense wires connected together, this is very important or the thing wont start! Connect a red and a black to either end of your resistor and attach it to the inside of the case, this will allow it to keep cool. (also you can put some thermal transfer compound between the case and the resistor if you want to help dissipate heat better). Why the resistor you ask? Well ATX power supplies are know as switched mode, and need a load to keep them switched on, this resistor basically couples it to a load state and forces it on. Connect a green and a black to your switch (you could actually use the one from the doner miggy psu if you wanted) Ok, on the cable from the amiga psu you have: Yellow-Black-Red-Brown-White These need to connect to the following colours on the ATX PSU. Amiga White goes to ATX Blue Amiga Brown goes to ATX Yellow Amiga Red goes to ATX Red Amiga Black goes to ATX Black Amiga yellow goes to earth, you can solder it directly to the mains earth as I have. Tidy up all your cables and fit your switch: Hey presto, a decent, powerful and stable PSU for your Amiga 5/6/1200. Kudos goes to Zetr0 for his pinouts on the amiga psu. Hope this tut helps some people out. Last edited by rave; 03 December 2014 at 11:25. Reason: Update pics

12 July 2007, 02:24	#3
eLowar Citizen of Elthesh Join Date: Sep 2003 Location: UK Posts: 949	No offense, but how about changing this to thumbnails with links to the actual pictures? This thread is 20 MB (yes MegaBytes) in size. A nightmare for dial-up users, plus the huge images make my browser run sluggish (okay, it's a slight overstatement, the scrolling is just not as smooth as usual) and my computer is not particularly slow and has plenty of RAM (this makes Firefox take up like 300 MB by the way). Edit: Good job with the thumbnails. By the way, sorry about jumping at you with criticism, I'd like to point out that I think you did a very good job, I just didn't think the huge inline-images were a good idea. I'm a little confused about the hot-linking issues. Where were the original big inline-images hosted? Last edited by eLowar; 12 July 2007 at 15:07. Reason: reaction to edit to first post

12 July 2007, 15:45	#7
rave Amiga's made me who I am. Join Date: Feb 2007 Location: Nottingham UK Age: 45 Posts: 178	@ eLowar, No worries mate The images were hosted on my own ISP webspace, I guess they stopped hot-linking? Last edited by rave; 12 July 2007 at 15:53.

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12 July 2007, 01:40	#2
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	@rave thanks for the kudos its a good pictorial, infact the largest i have ever seen (and i have a widescreen lol) great job rave! (i have also sent your finger prints off to the FBI LMAO!!!!) well done sir, a job to be proud of !

12 July 2007, 02:49	#4
T_hairy_bootson Workbitch 1.3 Join Date: Oct 2001 Location: Melbourne, Australia Age: 47 Posts: 2,084	24 inch widescreen at work running at 1920 x 1200 and I still cant see the whole photo when viewing the thread, nice detailed mod by the way, I have only ever used an ATU PSU as it was kinda easier with the switch already.

12 July 2007, 09:13	#5
musashi5150 move.w #$4489,$dff07e Join Date: Sep 2005 Location: Norfolk, UK Age: 42 Posts: 2,351	I fitten an ATX supply into my A2000 a couple of months ago when the original one blew up. Followed the guide here: http://www.ianstedman.co.uk/Amiga/am..._supplies.html And it works great. Gutted the new supply to fit inside the old A2000 PSU case - you'd never know

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