ATX PSU conversion

[mantisspider]

Hi Guys

Im at the point where i need more power in my trusty A1200.
My case doesnt have enough space for a internal AT PSU. So i only have two options, build my own external PSU from an old AT PSU and cutting up an old Amiga PSU for the connector. OR (which the option I want to go for. Convert one of the ATX external PSU things:



The only problem is that AT power supplies had a little button but ATX power supplies dont. Any ideas how I can get an ATX power supply to work on an Amiga? I googled but google hates me and just showed me A3000 tower conversion with no help on ATX powersupplies.

Cheers guys.... u the best :-D

[mantisspider]

anyone know if the Amiga Powershot 1200 ME-PSHT-12 is for external use?

[mantisspider]

hiya ,

anyone got a bigfoot psu they wanna sell :-D

[amigamad]

Download this from aminet http://wuarchive.wustl.edu/~aminet/hard/hack/atx_psu.lha

[redrumloa]

I don't have the pinouts handy, but a web search should pull them up.

Find the pinouts for both the A1200 power connector and the ATX power connector. Now just match up voltage to voltage, ground to ground and power good to power good. The ATX has 2 pins that need bridged to start it up, the pinout will show it.

Pretty easy and straight forward. I've converted PC power supplies for A500, 3000 and 4000 with no problems.

[JurassicCamper]

redrumloa wrote:
Now just match up voltage to voltage, ground to ground and power good to power good. .

A1200 does not have power good.

ATX power supply, cut the green wire and one of the black wires next to it as close as you can get to the connector, fit a switch between them.

Then Cut of the A1200 lead but leave about 6 inches left connected to the A1200 PSU. Strip back the insulation, this should reveal 4 wires.
Red, Brown, White and Black and wrapped around them shld ground.
Strip back these wires and measure the voltages.
Make sure none are touching Black or shld GND before you power up the A1200 PSU.
One happy strip back the the other end of the lead you cut off and join it to ATX wires.
Joining shld ground to GND on the A1200 lead so your left with just 4 wires to solder together.
[disclaimer]
white -12v
brown +12v
red +5v
black GND.

IIRC

On the ATX (allowing for standard colours)

blue -12v
yellow +12v
red +5v
black GND

you get the picture
[/disclaimer]

The switch will turn on and off your PSU.

Edit

Probably the simplest way as your A1200 is in a tower is to chop the green and black as mentioned above, join these to the switch already in your case, after removing your old PSU.

Then plug a floppy power connector on to the a1200 mobo floppy power connector. Make sure you get this the right way round. This then supplies +12 +5V and GND to the A1200 mobo, all you need now is -12V, cut the blue wire, solder it to a small nail, insulate and stick it into the center hole in the a1200 power connector on the mobo.

[redrumloa]

I'd personally recomend verifying voltages with a multimeter.

[voytech]

redrumloa wrote:
.."all you need now is -12V, cut the blue wire, solder it to a small nail, insulate and stick it into the center hole in the a1200 power connector on the mobo."

I remember when I did my first AT PSU -> Amiga conversion, nobody told me that i need this little blue wire (i searched on net, but there was a mess wchich wire to connect, somebody even wrote to connect the red wire to the -12v place!). Anyway i was surprised when my computer worked perfectly (without connected blue to -12v), till I wanted to listen any music or sounds from Amiga. Dunno if -12v is onl.y needed by Amiga's audio only - I didn't switched on my computer for 4 days (i f**** up my old original psu), till I confirmed with a voltometer wchich wire is that i need..

[voytech]

my mistake it shoul be:

JurassicCamper wrote:

and not
redrumloa wrote:

[mantisspider]

cheers guys its pretty scary all this chopping n voltages

[mantisspider]

i just seen one of these
http://www.yourstores.co.uk/quiet%20pc/ATX%20Conversion.htm

cheap and easy, using one of these with a powershot, im gonna try as soon as my powershots come and then post the images

[Wolfe]

mantisspider wrote:
Hi Guys

Im at the point where i need more power in my trusty A1200.
My case doesnt have enough space for a internal AT PSU. So i only have two options, build my own external PSU from an old AT PSU and cutting up an old Amiga PSU for the connector. OR (which the option I want to go for. Convert one of the ATX external PSU things:



The only problem is that AT power supplies had a little button but ATX power supplies dont. Any ideas how I can get an ATX power supply to work on an Amiga? I googled but google hates me and just showed me A3000 tower conversion with no help on ATX powersupplies.

Cheers guys.... u the best :-D

Amiga Powershot 1200 ME-PSHT-12 and customize this to your needs ( I assume you want to put the power board inside your 1200), I am currently investigating this option myself.  A matter of size on the powerboard.  
Or
Contact a cable supply company and ask them to make you one like
Redmond Cable   :-D
which is what I will be doing as soon as I find a powerboard that I can fit inside mine.   :-D

The powerboards support a power on switch mechanism and you can have one of those cables made also.  Review the docs that came with your power board.

Its going to be way cool when its done.   :pint:

[mantisspider]

cheers bud,

they an american company? what powerboard will you be using?

I like these small laptop PSUs rather than the big beige amiga ones.

[Wolfe]

@mantisspider cheers,

"they an american company?"  Yes, but you should be able to find someone locally.

"what powerboard will you be using?"  
I want to use an Audio Forge PW120 or 120a.  :-D

"I like these small laptop PSUs rather than the big beige amiga ones."  
 I want my A1200 desktop as a lean, mean spacesaving fun machine.

My current project is on my desktop A1200 with internal cdrw which limits my internal space more than normal.  I have some cardboard cut outs of the PSU's taken from some mates.  I am doing some plastic remolding work to add an additional inch to the upper A1200 case.  If I am successful I will be able to keep the internal floppy drive and will use the Audio Forge PW120, but if I loose the floppy then I will use the smaller square PW120a.  Either way I'm having fun.  Plus I am repainting the keyboard and will also paint the case something other than beige!    :pint:

[Doobrey]

redrumloa wrote:
I'd personally recomend verifying voltages with a multimeter.

I`d second that.. never ever go by cable colour alone...unless you can afford to replace your Amiga!
 The ATX spec recommends cable colour, but it`s just that...a recommendation.

 I just spent an exciting evening trying to get my spare A1200 working.. nothing but a black screen.I pushed and wiggled everything in sight, still no change..
 After the usual caffeine fix to reboot the brain, I dug out my multimeter and checked the PSU (standard beige CBM brick)... 3v on both the +12 and +5v rails !!
 Luckily I`d just got a MicroATX PSU..just needed a strip of terminal connectors and a toggle switch and I was back up and running in no time !