Atx Psu mounting guide in a post

[Retrofan]

Well, I'm making my A500/Atx Psu, and I've found an Atx one with the perfect measures and specs: http://www.ebay.es/itm/130559661001?...84.m1439.l2649 , SEASONIC-ATX-PSU-MODEL-SS-250SFD
 
250 watts; 125mm x63mm (75with fan) x100mm, and
+3.3V@18A,+5V@21A,+12V@16A,-12V@0.8A,+5VSB@2.0A
 
So I'm going to resume how to mount it in a post
 
The holes for the Psu's boards are in the same place, so you don't have to cut anything in the A500 one (incredible). You'll see that the voltages are written in the board, even the cable for "Ps-on" that goes to ground for the Psu to run, so really, really easy. You can use this guide too: http://www.ianstedman.co.uk/Amiga/am...iga_power_lead
 
Basically this image:
 

 
And usually (you have to test this with a multimeter):
 
Amiga Colour
ATX Colour
Voltage
 
RED
RED
+5V
 
BLACK
BLACK
0V/GND
 
BROWN
YELLOW
+12V
 
WHITE
BLUE
-12V
 
You can desolder the cables that you don't need from the board, but you need a powerful solder or desolder for that. I just cut them. Ground and shield go together to ground of the psu.
 
Before connecting it to the miggy I recommend to use the multimeter and test the voltages with the image above.
 
Well, finally you'll have to buy a thinner fan, as there's no room for the original. I've just bought this from China http://www.ebay.es/itm/251062116465?...84.m1439.l2649 , so I'll have to wait a month.
 
I'll be putting a voltmeter like I did in another (Gibs made it first).
 
The problem I've found is that my powerful miggy consumes a lot of power, so it wasn't booting shortening the cable even (well, it was booting, but only from the Idefix, not from the Scsi -yep, it has both to boot from-. I've got two more A1200's and they were booting without problems), and I didn't want to cut the cable as short as Amigakit's Psu. So finally I've used an Amiga power connector that I had from time ago (now you can buy it here) and I've connected it to a cable thicker than the original. It's black, but... it works . Listen... you don't have to use it if you aren't using as I am a BPPC, BVision, Delfina, DVD, 5 fans, Idefix, Subway..., Clockport expander, Acard and 2 Cf's adapters. The resistance of a given piece of wire depends of three factors: the length of the wire, the cross-sectional area of the wire, and the resistivity of the material composing the wire. The Amiga power connector isn't the best, and a long cable (2 meters the original) draws some power being so thin, so a thicker and shorter one has less resistance.
 
So this is how it is now (yes, it's so easy as you see here):
 

 
I forgot: You have to connect some (3) resistors to the 3.3volts line for this psu (250watts) to stabilize (thanks rkauer). I bought them here: http://www.ebay.es/itm/5W-Watt-5-Ohm...item5ae5fe42db 5W Watt 5 Ohm 5% Ceramic Cement Power Resistors
 
 
I asume all the responsibility. Ah, no.. lol... use this guide At your own risk , and careful with caps and old Psu's.

[Retrofan]

Well, it seems I can't edit my post. So... Forget about the fan. The chinese one is a ****. Now I've bought this: http://www.ebay.es/itm/310275977662?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
 
And you must cut something if you want to use an 80x80x15mm fan like I do; you have to cut the supports where the Psu screws, leaving them with around 7-8 mm.
 
I've closed it. This is how it is:
 
 

 
 

 
After you connect the voltmeter (if you do), you have to adjust it with an screw using a multimeter. I've got 4,93 volts in the 5 volts line.

[Retrofan]

Hi
 
@gizmo,
 
What are you a brown noser, you are suppossed to tell him that he just messed up an original Amiga power supply by using a PC power supply, and that the original did not have that blue display.
 
Now it would have been better if he did not contaminate his Amiga with a PC supply by using a mac supply instead. Remember if we are going to change this to a mac board we have to think McDonalds.
 
Otherwise very nice.
 
Smerf

Hi. Thanks for your opinion. I woudn't use an ATX psu if the Amiga one could power on my miggy/s. I know, some will like it and some won't :banana:
But I can't use the original. BTW: Don't use a Compact Flash as hardrive if you want it like it was... and forget about the Indi.
 
In my 2nd post I was having to cut the supports, but now I'm going to try also with a 60x60x10 fan fwith more revs and more noisy, http://www.ebay.es/itm/370601614556?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 That's the one I use in my C=64 ITX. It's a lot more noisy, but has a good airflow, and if you use it you shoudn't cut anything.
 
Also in the photos there isn't the small board that the psu has and that goes connected to the switch, I added it later.

[Retrofan]

Well, here it is completed. Sorry that I can't edit my posts, I wanted it to be in only one. If you want it, click here: http://eab.abime.net/showpost.php?p=819819&postcount=89
 
Now I've connected the small board, the PFC. For what I've read it helps to lose less power... but running the miggy I've got 4,9-5v, like before (edited).
 
I've taked also another cable to ground, from the pcb (top right corner) to the ground of the power cable.
 
Photo:
 

[Retrofan]

I've done also another version with the same psu. This delivers 5,20v before powering on the miggy, and exactly 5,00v with it running:



I prefer the other design, but I had an A500 psu case with the top broken, and it doesn't look bad.

[Retrofan]

I've done also another version with the same psu (another I bought). This delivers 5,20v without anything connected, and exactly 5,00v with the miggy running:



I prefer the other design, but I had an A500 case with the top broken, and it doesn't look bad.

[Retrofan]

som99 you've done a great work too. I like it (Off topic... what has hapenned with the smilies here in A-Org?). Pfff...
And you are using a pico psu in the second... nice. I use it to power on my mini-ITX C64, with which I'm posting now.

I did those cuts you talk in my first A500 psu mod. And why hotglue the fan? Because I can't screw it (in the first design) if I don't make holes in the case.
paul1981 I don't have more room in the case for the fan in the first design. In the latest, as you see there is more airflow.... But I tell you it isn't necessary in the first, it runs extremely cold

[Retrofan]

Ah, ok I thought it was a pico psu for the connector... yes, I know the Atx psus all have also that connector... just my idea because I retained it in mine, like you've done.

You don't have to wait to see it http://eab.abime.net/showthread.php?t=58992