An Amiga 1200 *internal* power supply

[aeberbach]

I put a Mean Well RPT-60B where the floppy used to be in my A1200

The whole thing sits in a 3D-printed mount. The power cord and a switch sit at the back right of the machine where you can reach them. It's a tight fit, but after a lot of prototypes I got it to sit nicely with space around it.



A bit more writing and a couple more pictures at http://www.grayunicorn.com

[Marlon_]

Nice! i did something similar with a built-in PicoPSU. Out of curiosity, why did you use a Meanwell instead of a PicoPSU?

[aeberbach]

The PicoPSU is DC-DC, so you need an external converter (a good 12V supply). That means you still have a brick on the floor or a big plugpack at least? I just wanted to plug into the mains same as a Mac mini - single IEC C8 cord.

[Marlon_]

Originally Posted by aeberbach

The PicoPSU is DC-DC, so you need an external converter (a good 12V supply). That means you still have a brick on the floor or a big plugpack at least? I just wanted to plug into the mains same as a Mac mini - single IEC C8 cord.

Ah, I see.

I just have a tiny 12VDC adapter for my PicoPSU, way smaller than the original powerbrick anyway.

I personally don't want to mess with mains power (230VAC) as you'd need to be a proper licensed electrician to work with that in Sweden. Messing with something like that and it for some reason fails and causes a fire, it would invalidate my insurance, since I'm not a licensed electrician. :P

[jbilander]

Nice, note that the Mean Wells are usually specified with a minimum load on the different rails for stable operation. The 5V shouldn't be a problem since almost everything in the amiga draws from the +5V but check the specs for 12V and -12V. You might wanna put a suitable power resistor on each of those lines (to GND) to at least have a "dummy" load above the threshold instead of zero amps.

[GearCross]

That looks awesome! Will you provide the .stl files for the frame? I'd love to replace the huge brick sitting under the desk with something like a picoPSU, but this is even better given the fact that I have absolutely no use for the floppy drive.

Cheers.

[aeberbach]

I will definitely share the model but need to revise one or two things. When you use something for a bit there are always a couple of little improvements to discover.

[GearCross]

Nice. Looking forward to it. I'll hold off modifying a PicoPSU for now then

[Photon]

I prefer to not bring heat and AC into the case, because I want to put other stuff that draws power inside that also develop heat But put like this away from the mobo and near the vents, it's probably fine for unaccelerated Amigas

I think PicoPSU is the best choice, and I heartily recommend it. You could put the small converter inside and get a nice DC jack to plug the 12V PSU into, very snazzy. Because it's so small, it can be a challenge to fasten securely, so it doesn't come loose in transport/moving/storing. This looks like a secure solution to me.

[GearCross]

I can see what you mean... I actually have absolutely no clue how hot an 030 or over heat up. Most I've read is that, when overclocked they tend to be quite toasty, just like PPCs.

I wonder if it's possible to add a fan (50 or 60mm) to the top of the PSU cage; that would take the heat from the PSU out of the equation, and also probably force air to circulate in the case.

In my case, given I intend to leave it with the stock EC020 and 8MB FastRAM, it should be just fine. Most I intend to further add/modify to my A1200 is a new case and either connect it to the network or a PCMCIA CF reader to transfer files from and to the computer. Though, the RAM expansion will interfere with the slot

[aeberbach]

In this case there is no need for forced air cooling. The Mean Well module can sit in the original Commodore power supply brick with very little cooling, only the slots cast in the plastic box for cooling and you cannot feel that it is getting warm. This is with a moderately expanded Amiga 1200 - 80MHz 060, 32M RAM, sold state drives (CF, microSD and DOM).

Inside the case in this 3D printed enclosure it is the same deal, no warmth to feel at all. The modern Mean Well module is really very efficient and produces very little heat and what there is would go straight up through case slots directly above (not that I have ever felt any so far). Just as processors are many times better nearly 40 years on, so are power supplies.

The 060 chip is a different matter. I got it with 64M and a fan on it but removed one DIMM module to install a 10cm high heatsink on the chip instead of keeping the RAM and the fan that was there. (The heatsink can't fit with the RAM in place on the top side, 32M is plenty for me, can't stand the fan.) I _may_ design a duct to direct air into the 060 heatsink, and that will have a fan, but it will be controlled by a microprocessor and would only activate proportionally if some threshold, possibly 50 Celsius, is reached.

[dalek]

Looks neat!

Those terminal sockets you used for the wires to the PSU DC-out posts - do you have a source for them? I'd like some but don't even know what they're called to google for them. They look crimp on?