A4000D PSU Replacement Questions

Im looking into such a mod as well. My soldering skills are nihil. So looking for a mod on the easy way.

ive got enough ATX PSU's lying on the shelf.. is it just a matter of picking the smallest one (to fit in original PSU housing),with the best 5v spec as stated earlyer on this thread?

Was searching and found the following item wich could help
http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=615

Anyone got experience with this one?
 
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LOL! The switch you linked to is the one that I used in my ATX project. The only reason I had to do any soldering was because I was mounting everything inside an old A4000D PSU shell. I would definitely recommend that switch from AmigaKit.

Heather
 
Let me see if i got this straight: i actually bought an ATX<->A4000 psu adapter from a member here, which has no switch on it. Just a direct ATX to mobo dongle. I understand there has to be a switch between two pins on the ATX socket to send the triggering signal so the psu can start; anyone doing this, have you actually installed a "reset-type" switch on the A4000's psu case instead of the original on/off switch? Does that engage nicely with the power shaft from the front fascia?
Heather, i'd appreciate if you could tell us the length the switche's axle protrudes from the psu case, remember some time ago i was waiting for you to finish the mod so you could tell me? :)
Sorry for having so many questions, but as soon as i get well this is one task i need to get finished...
 
@salaxi54

I'm not exactly sure how the switch is wired into the ATX adapter but I know that the switch itself is just like the original A4000D switch: Pushing in the first time turns on the PSU and the switch stays pushed in; Pushing in the second time turns off the PSU and the switch pops back out. It's a perfect replacement for the original A4000D's power switch and the power rod that goes to the front of the computer seems to be at the same distance as the original PSU.

I'm not sure the exact length of the axle but I do have the A4000D apart right now and could get a measurement for you tonight (as long as I remember!). :wink: You can see my PSU Photo Booth thread for some images.

Take care,

Heather
 
Im currently having my Amiga 4000 refurbished and my next step is the psu, it works perfectly fine but it has an overloud fan which spoils the enjoyment when the computer was switched on.

I opened the psu and noticed the fan cable was fitted direct to the pcb so theres no chance of me changing it. I was hoping it was 2 pin fan affair so it could be changed with ease but I was wrong!

So what are my options, i doubt ill be able to get a replacement psu as im guessing they will all suffer from this problem. Is there no company that has reproduced these, or alternative, psu's? or is there anybody out there that modified these psu's and sells them on the black market? Im fairly sure theres a market here for modified psu's as almost everyone ive seen complains about this problem!
 
Im currently having my Amiga 4000 refurbished and my next step is the psu, it works perfectly fine but it has an overloud fan which spoils the enjoyment when the computer was switched on.

A simple fan replacement is an easy task. If you are not confident, ask a TV repairsman.

I opened the psu and noticed the fan cable was fitted direct to the pcb so theres no chance of me changing it. I was hoping it was 2 pin fan affair so it could be changed with ease but I was wrong!

Again, two wire soldering is easy enough.

So what are my options, i doubt ill be able to get a replacement psu as I'm guessing they will all suffer from this problem. Is there no company that has reproduced these, or alternative, PSU's? or is there anybody out there that modified these PSU's and sells them on the black market? Im fairly sure there's a market here for modified PSU's as almost everyone I've seen complains about this problem!

No black market, sorry.

You have to locate a mini (or micro) ATX power supply and replace the innards of the A4k PSU with it. Not exactly a trivial job, but pretty easy to do.:nod:
 
Im pretty sure theres a couple of tv repair shops near me, i never thought of asking one of them, thanks for the tip (y)

I know its a pretty easy task, but its only easy if you know what your doing! Knowing me ill either kill myself and kill my Amiga when I plug it back in, so its damage limitation really.
 
Im pretty sure theres a couple of tv repair shops near me, i never thought of asking one of them, thanks for the tip (y)

I know its a pretty easy task, but its only easy if you know what your doing! Knowing me ill either kill myself and kill my Amiga when I plug it back in, so its damage limitation really.
Yeah, I know the feeling.
homer_breakfast.jpg
 
@SDG: After looking at the pics in your Photo Booth thread, i'm even more confused! :unsure: From what i can see, there's two wires (green and black) soldered to the switch, and they don't look like they end up to the adapter itself, more likely to the PSU's pcb is what it appears to me..
On the other hand, the switch pictured in amigakit's description is even more confusing, looking like it comes out of the socket itself. I may be wrong, so please tell me if the switch connects to the socket, or the psu's innards?
http://amigakit.leamancomputing.com/catalog/images/atx-psu-adapter-switch.jpg
If i wanted to start an ATX psu i'd short pin 14 and gnd. But that would need an instant switch, one of a momentary action. Keeping it pressed for more than 4 seconds would power the psu off again.
So, my thinking is that there's some sort oh modding to the psu itself.
Suggestions anyone?
 
To switch an ATX PSU on you must short the green wire/pin to ground.

Black wires are ground.

Using an on/off switch to short the green wire is the logical solution.
 
To switch an ATX PSU on you must short the green wire/pin to ground.

Black wires are ground.

Using an on/off switch to short the green wire is the logical solution.

If that is so, where does the green wire connect? Try using an on/off switch between pin 14 and ground! You'll get power, power off after 4 seconds, and that keeps on going with a repetitive cycle... You can try that on a regular peecee, by holding down the power switch for more than 4 seconds. Oh, say, 30 seconds is enough to get the idear..
 
Nope, the pc have a proper latching circuit. When holding the power button the motherboard will shut the PSU down after the giving time.
 
Although i still wonder where the green wire is connected over at Heather's pictures, i have decided to take the easy route! After reading Ian Stedman's instructions, i think the easiest way is to hardwire the mains switch on the psu, and bring it through the on/off switch at the front...
Once my health gets better, it'll be modded in no time :)
 
A4K Power Supply ratings?

A4K Power Supply ratings?

So, I'm getting ready to build out a new replacement for my a4000's power supply, and I can't quite sort out what the power requirements are for these things.

The original SkyNet PS is 145W, with +5Vdc @ 18A, and +12Vdc @ 4A. Somewhere along the line it was "upgraded" to 230W, with +5Vdc @ 23A and +12Vdc @ 9A. The workmanship is a bit below my standards, and the fan sounds like a jet engine, so it's time for an upgrade...

My goal is to retrofit an ATX PS board into the original shell, and I found a very good candidate (size-wise) with these specs: 240W, with +5Vdc @ 20A, and +12Vdc @ 16A. Of course, it can't push both those rails at those maxes, as that works out to 296W, but that's a different story about PS ratings...

But, what's the minimum comfortable ratings for +5Vdc/+12Vdc for an A4K/040, with a HDD, CDROM, floppy, and (soon) a Deneb, Picasso IV/Cybervision, and maybe a CPU accellerator?

Thanks!
Robert
 
The original specification of the A4000 PSU is more than enough for such a system.

My advice, if you can solder: just replace all the electrolytic capacitors (for good brands!) & the bloody fan from the original power supply.

This will make it future-proof for at least another eight years to come.
 
I'd love to do exactly that, and it was my plan originally. Unfortunately, somewhere along the line (looks like in '97), someone "upgraded" it by cramming an ATX power supply board in there, and not taking a ton of care in doing it.

It's wedged in at an angle, with a mess of wiring, and just isn't quite the way I like things...

So, if I'm going to replace it, may as well replace it with something newer, more efficient, and hopefully quiter and cooler.

Sounds like the replacement I found should work nicely, then.

Thanks (again!)
WhyreByter
 
@SDG: After looking at the pics in your Photo Booth thread, i'm even more confused! :unsure: From what i can see, there's two wires (green and black) soldered to the switch, and they don't look like they end up to the adapter itself, more likely to the PSU's pcb is what it appears to me..

I think you missed her thread, which is here: https://www.amibay.com/showthread.php?t=7593

You can see she did a full mod into an old psu shell, thus using the original start button.
 
FYI: I've posted details of my a4K PSU replacement in my A4K rebuild thread.

Cheers!
WhyreByter
 
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