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AuthorTopic: Amiga 4000 power supply  (Read 582 times)

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Offline darksun9210

Amiga 4000 power supply
« on: October 17, 2019, 01:16:50 PM »
following my CD32 power issues, wondered if my "dead" a4k was due to power issues as well.

turns out the ATX to A4k PSU adapter has broken 5V and ground lines in the plug to the mainboard, and the SFX flex-atx type PSU is cooked. as on swapping the PSU and re-terminating the power lines into the plug, i get a power light, and the floppy drive does it's disk seek chug.
years i've been trying to figure this out on and off! YEARS. it couldn't be the home brew looking ATX adapter and brand new (at the time) PSU gone faulty could it. oh no, that should be absolutely fine.

good grief! anyway. my A4k is ALIIIVE! and i am more than super happy after the time i've spent faffing about with it over the years. but i need a more permanent power setup than an old PC with the side off sitting on top of the A4k's open case - looking like some technological cross-breeding experiment going wrong.

the original PSU was rated at 145Watts if i recall. These PicoPSU things are rated up to 160W with the right mains to DC12V adapter. although it seems i can only get 120W mains adapters at the moment. would this be enough?

current projected spec of hardware i have installed,
A3640 CPU card - as original, 16 meg ram.

hardware i have to go in that is not installed.
Mediator PCI thing- not sure if i should actually bother with this - as i suspect it'll be more trouble than its worth
Bigram256
X-Surf100 + Rapid road USB
IDE to CF adapter - no hard disk any more. whats the point with current flash options?
DVD Drive
Floppy Drive
PCI SB128
PCI NIC - now pointless due to the x-surf100
and in the future a graphics card of some description. either a CV64/3D, or Voodoo3 on the mediator

this should all fit in the 120W power budget?

lastly, i want to make sure that the power pins are properly connected. anyone know how to get the pins out of the power plug that goes to the A4k mainboard so i can properly crimp the wires? for the effort i might just order a new power adaptor?

thanks again!
« Last Edit: October 18, 2019, 12:32:42 PM by darksun9210 »

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline trixster

Re: Amiga 4000 power supply
« Reply #1 on: October 17, 2019, 06:07:45 PM »
Does the pico psu give you enough on the 5V line to power the board and your zorro/pci cards?

My old original skynet A4000 psu put out 18A on 5v, I don’t think your 160W pico will deliver more than 8A
« Last Edit: October 17, 2019, 06:14:26 PM by trixster »
[SIGPIC][/SIGPIC]A1200 + 80Mhz B1260 + Indi AGA2 + Ide-fix Express | A500 | A3000 + 50Mhz A3660 + CV64 + Deneb + 486SLC + ZorRam
A4000/040 + 66Mhz  Cyberstorm Mk2 + Indi AGA + Voodoo 3 + Sonnet G3 + Deneb + Prisma | SNES | C64 | CPC6128 | MD | 3DO
Acorn A3020 | A3000 | A420/1 | Atom | Master Turbo | BBC B | Atari Falcon + 100Mhz CT60e | PS1 | PS2 | Saturn | Atari Jaguar
 
The following users thanked this post: darksun9210

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #2 on: October 18, 2019, 09:44:19 AM »
ah, yeah. That's only about 40Watts on the 5V rail. good point, i hadn't even thought of that.

alright. i'm going to look at something a litttle more pokey as a PSU then. Plus a new ATX adaptor as given there is only ONE 5Volt line into the board, i want it to be good!

Cheers,

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #3 on: October 18, 2019, 11:31:28 AM »
so in light of a little digging, from what i've seen, the A4k is on paper - spec'd to take 10A on the 5V line. And yes, you're spot on, the original PSU seems to be a bit special being able to push 18Amps on 5Volts.

seems PC PSUs these days are all geared up for loads of amps down the 12Volt line, so even units in the 200-350Watt range don't seem to push more than about 14 Amps on 5Volts.

so i'm going to pull my existing dead flex-atx psu, and ATX-to-A4k adapter out, and replace it with a 500W SFX psu. Massive overkill it seems, but that's the smallest i can get drive more than the previous 18Amps on 5Volts. paying a bit more for modular too, so i don't end up with loads of wires that i don't need cluttering up the case.

if anyones interested, getting a silverstone SX500-G. Rated to 5V@22A 12V@41.7A(!) and the usual -12v@0.3A
A4k adapter by way of amigakit

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline trixster

Re: Amiga 4000 power supply
« Reply #4 on: October 18, 2019, 11:51:13 AM »
I use a Corsair SF600 SFX PSU, and I know someone with an SF450. Both work well with fully loaded, maxed out A4000s.
[SIGPIC][/SIGPIC]A1200 + 80Mhz B1260 + Indi AGA2 + Ide-fix Express | A500 | A3000 + 50Mhz A3660 + CV64 + Deneb + 486SLC + ZorRam
A4000/040 + 66Mhz  Cyberstorm Mk2 + Indi AGA + Voodoo 3 + Sonnet G3 + Deneb + Prisma | SNES | C64 | CPC6128 | MD | 3DO
Acorn A3020 | A3000 | A420/1 | Atom | Master Turbo | BBC B | Atari Falcon + 100Mhz CT60e | PS1 | PS2 | Saturn | Atari Jaguar
 

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #5 on: October 18, 2019, 12:28:00 PM »
just looked at the specs of those; yes those look like the business too!  :)

ok at least this way i won't be worried about what i put in the machine going forward.
A Voodoo3+fan especially, as the amount of heat i remember the one i had in a PC generated - it can't have been light on power requirements. At least compared to what passes for amiga power requirements  ;D

i remember the issue with my original A4kT running a standard AT type PC PSU. once i had that thing fully built, it'd eventually melt/burn out the tongue connectors in the PSU power plugs about once a year or two. easy to replace at the time though. just annoying as the symptoms were just the machine becoming more and more temperamental.

but i've learnt. don't skimp on power.

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline beller

Re: Amiga 4000 power supply
« Reply #6 on: October 20, 2019, 07:52:55 PM »
What did it take to fit the new power supply?  Anything special?  Pictures would be nice. I think my A4000 will be needing one soon...
 

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #7 on: October 21, 2019, 10:46:23 AM »
Sure thing. Sorry i didn't consider this to be picture worthy, and the PSU hasn't arrived yet so still running the PC-to-A4k umbilical for power at the moment - so it's not pretty.

What i have got, and it's actually a bit of an excellent bonus, is the original PSU was modded by Motorollin' years ago.
so i still have the original PSU case, although it's been cut and finished into more of an open box frame, with a flex-atx PSU fitted inside, and a mesh grill on the back with the original PSU power plug still in place to feed whatever is fitted inside.

this makes cable routing a lot easier, and maintains the hard disk mount-plate screw holes.
also lends more structural strength to the back plate supporting the top case of the machine as a whole.

the one thing i AM going to add, though, and i didn't really think about it when all i had in here was an 030, is either a 92, 100 or 120mm fan on the back blowing out the mesh. as the A4K's only source of airflow is, or was, the PSU fan. I'd like to be able to put the lid back on at some point, even though i know the most normal state for most running amigas is with the lid off. ;D

anyway. will post up some shots as and when.  :)

oh yeah, amigakit basicly "next-day"'d the A4k-ATX adaptor over to me so shout out to those guys  8)

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #8 on: October 22, 2019, 10:16:30 AM »
The PSU's here, but i've not done much yet.

So this is what i'm working with, the original PSU body, cut and edged, with the old replacement Flex-ATX PSU half out, and the drive mount plate still attached.:-


Funnily enough the old flex-ATX psu was only rated to about 60watts on the 5volt rail. so that's probably why it doesn't work any more. live and learn.

and the new PSU sat on the old:-


so width wise it's exactly the same near enough, even the screw holes seem to line up. so i could just put it in as is,  but i feel i'd loose some structural, plus have to figure out a new mount for the actual on/off switch.
i can't sit the SFX PSU vertically though, as it's about 5mm above the top of the case, so it'll have to go horizontally.

i did find this:- https://www.thingiverse.com/thing:2792761 for a 3d print of an adapter for an SFX psu with button mount.

but i'm lazy so i'll try and bodge together what i've got.

with regard to fans, a 120mm fan would *just about* fit at the back of the A4K's PSU space, with nothing else top or bottom. a 92mm fan *may* leave enough clearance around the mains power input socket. an 80mm fan would fit fine.
but the SFX PSU i had has a 92mm fan already, so i'll see how that fairs before adding anything else.
« Last Edit: October 22, 2019, 10:21:15 AM by darksun9210 »

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330
 

Offline beller

Re: Amiga 4000 power supply
« Reply #9 on: October 22, 2019, 04:46:35 PM »
Thanks!  Your description and pictures are great!  Helps me to think about the job. 

Best tutorial I’ve seen!
 

Offline darksun9210

Re: Amiga 4000 power supply
« Reply #10 on: October 23, 2019, 10:19:54 AM »
so i hit a little roadbump. the old flex-atx psu power socket was soldered to the power cables coming from the socket of the original PSU, with some insulation stuffed around the contacts. so to remove it, i had to clip the cables.

i could fit the SFX psu inside the original A4k PSU given that i can allow a bit of the SFX psu to poke out the side of the PSU frame while it was installed in the A4k - but that would leave me with a decision to make if i wanted to keep the original PSU case.
1. re-attach the power lines from the old socket directly as per previous, no good for swapping out if needed in future, also i'm a talent-less moron when in comes to soldering.
2. find a 90degree IEC screwable power plug that'll fit between the mesh on the back of the PSU box and the new SFX psu itself - to put on the end of the wires from the socket, or a cable with a socket on one end and a plug on the other. both loosing me valuable interior cable routing space, and figuring out a mounting solution for the SFX psu in the old psu case.
3. i ignore the original socket and poke a hole in the mesh to allow a power cable to plug directly into the new SFX psu. not pretty.

I had a look last night for plugs and cables, and not really knowing what i'm looking for, i was drawing a blank on finding a way of attaching the existing socket to a plug, or a single moulded socket\plug combo piece that would fit the bill.

now i mentioned i like to take the path of least resistance in my down time, and that there was a thingiverse thing for fitting an SFX psu with a 3D printed "adaptor".
so i got in touch with a friend of mine and he started a print run for me. at the time of typing this, still got 5 hours to go apparently!

so. Original PSU case with SFX PSU next to it and plugged in for... erm... testing.. :)


3quarter profile shot to see the size difference a bit more


the flex-atx added in. perspective isn't working to nicely here, as the flex-atx does fit inside the normal PSU case without a struggle.


What i'm printing:-


the start of the 3D print (an hour or two in)


how far it had got when i left for work this morning
« Last Edit: October 23, 2019, 10:44:35 AM by darksun9210 »

A500 Vampire2, A600 Vampire2, A1200 Bliz030, A1200 Bliz040, A1200 BlizPPC, A3k CS MK3060, A4k C=040, CD32 TF330