USB-C power for your Amiga 500, 600 and 1200 | Hacker News Reader

USB-C power for your Amiga 500, 600 and 1200

retrousbpower.com

91 pointsnickt66 comments

The move to USB C as a generic DC power standard is fantastic, at least as a consumer. I'm 100% on the USB C bandwagon. Even my coffee scale and room temperature gauge charge through USB C. Going from the days of eight different poorly designed AC->DC adapters with barrel jacks, this is heaven.

USB PD has it's quirks, that's definitely true, but I'll take it over the alternatives any day if I can use it on all my devices.

I am generally in the same boat, but I'll admit that I love my Macbook which can charge over either USB-C or the Magsafe (with USB-C at the other end), because I basically never worry about breaking the power connector when I'm using the Magsafe, but can still charge over USB-C as well.

Is magsafe 3 actually anything more than the VBUS and CC pins for usb-c in a custom form factor? Apple od course doesn't document it, and I can't find any solid reverse engineering blogs about magsafe 3 (just magsafe 1 & 2).

I assume apple still has parents here (magsafe is less than twenty years old), but I can't wait for a standardized USB-M magnetic charging connector.

Funny I just replaced the power port on my 2011 thinkpad with a usb c port (https://www.tindie.com/products/mikepdiy/lenovo-charging-por...). I guess as long as fundamentally the charging standards don’t change we’ll be able to do this with ever increasingly old tech.

$23 plus shipping? Fuck that haha

Didn't know this was possible!

I have a bunch of old thinkpads and need to keep around 3 different chargers (round, rectangular and usb-c). Could be great to go all in USB-C at some point.

Lenovo chargers are 20V. USB-C PD supports that and there are "Type C to Lenovo" cables with integrated circuit to negotiate the voltage. You need to have the correct wattage of the USB-C charger though.

There are adapters available for USB C cables if you don't want to modify your computer but want to use the same charger.

https://www.aliexpress.com/item/1005005233750368.html

https://www.aliexpress.com/item/1005005703577535.html

Why on Earth would you want to replace the robust, round connector with fragile USB-C?

I imagine there are other reasons people might want to do so, but from the Tindie product page:

"but long story short, I just love to travel with maximum 2 cables and 1 or 2 power bricks depending on the number of devices I carry"

Firstly; the round « robust » connector started to malfunction, the cord would slowly drop out of the barrel.

Secondly; My phone is usb c, I only carry around a single cable type now, I feel like I have adcended and reached cable heaven.

One of the few computers I regret getting rid of is my Amiga 500. What would I use it for? Not sure. But… Something.

I saw our old A600 in storage at my parents last weekend. I’ll go get it one day, so many good games on there.

They are throwing it out next weekend, better hurry.

Can't stress that enough. Every week in retrocomputing forums there's some such story.

Simply cannot expect family to actually value your treasures.

Oh man, I did the same thing and very much regret it. It's like I gave away a important part of my childhood. When I have the time I'll buy another one and probably just fiddle around with it. Play all the old games I used to like too I guess.

If you go after it and buy an Amiga, don't forget it is much about preserving a vintage computer at this point. And not just the computing/gaming or whatever you remember doing.

I did this, and I'm not sure it was what I wanted.

If you're looking just for the experience and not the burden of caring for vintage equipment, the A500 mini has good reviews (and looks like they're making a large size version later this year).

Save yourself the money and just use the raspbian they based it on.

That works on the Raspberry Pi you probably already have.

There's also PiMiga, WinUAE, fs-uae and minimig (miSTer branch).

Can you go into more detail? How much effort is it to keep it working?

Apologies for giving you the boring 'it depends', but it really does depend ALOT where you start off and what you wanna do. I can tell you my experience.

If you start off with a stock Amiga finding off the attic you can pretty much expect anything. This is rock bottom. I did this and in hinsight it was a mistake. Decades of sticky filthy dust, bugs, rust, yellowing, bumps, scratches, stickers, missing port pins, screws, ram lid, cracked up soldering, leaky batteties, unresponsive keys. But I had a working floppy, and it actually booted. Lucky me.

You should buy a confirmed working Amiga from an enthusiast. These guys usually have a lot of them accumulated over the years and has probably tended to at least basic things. I did this after I gave up my first. You'll find them on Facebook and they are great helpful people in your demography probably.

Now you want a screen. Do you really want an old CRT, or do you wanna adapt to a modern (HDMI!) screen? No approach is correct, you just have to pick one

Now you want data. The floppys are old and were already a flimsy tech when new. Many don't work anymote. I found I wanna work around this with and download floppy images off the internet instead. There are many ways to do this by fitting something modern on the Amiga. Gotek to name one solution.

Sorry for the long answer, but to go back to my original point. This is a huge topic with a large community and many commercial actors who can sell you things to fix old computers.

I don’t miss my old Amiga that much. But I do regret that I didn’t keep copies of source code for various projects I did on the Amiga. Mostly for nostalgic reasons of course.

I threw out my 2 A500's into the electronics recycling when I moved houses 15 years ago. I wish I had kept them now that I have the space. I didn't have a monitor though since my 1084s was busted so I never used the computers.

An interesting detail is that it has a physical switch to turn it off.

> Utilizing any 12V-capable USB-C power supply

Are different kind of USB-C power supplies, some not outputting 12V? Does it mean that normal phone chargers aren't good?

Yes. Your random usb-c phone charger may not do 12 or 20 volts. It only needs to do 5 volts to charge a phone. A usb-c laptop charger will do more volts and amps which means more watts.

In fact, most don't do 12v. The common voltages are 5, 9, 15, and 20 volts.

Some chargers don't do 12V or 15V, but will do 5V, 9V and 20V. This depends a lot on the total wattage. Lower watts, like 20W or 30W can or can not do 15/20V, but 12V@1.5A (18W) and 12V@2.5A (30W). Usually the >65W will do most of them, plus PPS. Always check specs. And what is the input voltage this powerplug expects; 15V or 20V?

> Utilizing any 12V-capable

If so, this is usually at a VERY low wattage. they usually go to a max of 2.5 or 3A max at 12V. I would expect it would use 20V and step-down as 20V is more generally available at a high Amperage. (Note: 3A is the max possible for cables without an E-marker, os if often regarded as a ceiling). This would have made the device much bigger (and more versatile. a clear trade-off).

Actually, I am more concerned about -12V, ... at 0.1A. That seems rather low. Also, the 12V rail itself is only 1.0A. The original supply did 12V@2A and -12V@0.5A if not mistaken, and so does the C64psu.com. Overall, rather low Amp values. This might affect 'stability' if your machine is expanded (although it claims: "of even the most expanded configurations"). Curious if they can share some details. I have a BlizzardPPC in my A1200.

> allows users to tap into a vast array of affordable and readily available “power bricks”

if DC5521 at >12V to 20V is possible, that would be great, as this allows you to use a Lenovo or generic laptop brick, or a USB-C trigger cable. Perhaps something I should make ...

One would hope that they based their power limits on real-world measurements.

Maybe the original power supply was oversized to avoid efficiency loss near 100% load, or because precise overcurrent protection wasn't available?

I'd rather have headroom than running in an overcurrent situation. I hope than can provide more details about the capability and what they tested. I moved away from the stock supply many moons ago as it wasnt as stable anymore, plus of powering the accelerator board, plus the CD-drive and harddisk

The A1200 at least will actually function without -12V, but the audio will be bad.

I had crackly audio problems. I swapped the A1200 motherboard (a few years back when they were still fairly cheap on eBay), and still had the same audio problem. Only then did I investigate+repair the PSU issue.

Recently built a replacement Amiga PSU from a MeanWell PT-65B board in a 3D printed case. This USB-C option would have been neater and easier (so long as it puts out enough power for a PiStorm as well as the Amiga)

Pistorm would be 5V. But yeah, perhaps an idea to move away to this instead... Most likely less power hungry. Haven't had the time yet... The place I am in is hard to get shipped in reliably.

>Only then did I investigate+repair the PSU issue.

This is why you always check the voltages first.

In these machines +/-12V is only used for Audio op-amps, RS232 Line drivers and the floppy motor. everything else is running on the 5V rail.

That is not completely true. The opamps for sure, but the 12V rail is also used for external devices, eg harddisk, cd drive, expansion cards, etc.

Too low current on the -12V rail can cause crackling sound. I use my A1200 machines mostly for this, although more using AHI than before.

> the 12V rail is also used for external devices, eg harddisk, cd drive, expansion cards, etc

External drives should have their own power supply and indeed the A590, A570, GVP drives etc all do.

The A500/A2000 Technical Reference (page 227) shows that the 12V current limit on the expansion connector is 50mA

The A600/1200 don't even have the expansion connector

Page 5 of the TRM specs the -12V supply at 100mA

> Too low current on the -12V rail can cause crackling sound.

Maybe if the current is zero

TRM: https://archive.org/details/CommodoreAmigaA500A2000Technical...

I thought the trapdoor (cpu slot) also exposed 12V, but just checked and I was wrong. Thanks for clarifying that the 12V rail might be sufficient.

Principal designer of PowerShark here. Original PS spec from Commodore defined 5V/3A, 12V/0.5A and -12V/0.1A as max. load (http://www.kaiiv.de/servicemanuals/A500_Power_Supply_Specifi... page 3) It was in later models bumped up to 5V/4.5A and 12V/1A, with -12V unchanged.

In actual use, a "wedge" Amiga consumes just below 30mA from -12V line.

Visit our page, there is now a detailed FAQ and a list of various USB-C power supplies we tested with PowerShark.

> An interesting detail is that it has a physical switch to turn it off.

It is the switch for turning the computer on. The original power supplies all had it on the box.

I had my power supply on the floor under the desk and was used to flipping it on and off with my foot. I used the heavy supply from my A500 with a A1200 later.

I imagine the physical switch and the grilles are a tribute to the original power supplies (A500: https://i.ebayimg.com/images/g/wbYAAOSwW1JlX0FB/s-l1600.jpg). The site doesn't give any hint about the color, but I would bet it will be beige...

That being said, the claim that it works with "any 12V-capable USB-C power supply" sounds very ambitious. Is any 12-V capable USB-C power supply capable of delivering 60+ watts?

No, mostly limited to 2V@2.5A (30W) or max @3A as that is the max amperage for a cable without an e-marker.

Confused by:

> allows users to tap into a vast array of affordable and readily available “power bricks”

followed by

> Furthermore, portable USB-C “chargers” are also supported,

So I expect it means it has a USB-C plug and you can feed 12V directly like with the Miniware / Pinecil soldering irons. Though, is this protected for overvoltage?

> If an over- or under-voltage

So, most likely you can only feed 12V. A Dell-brick , like the DA-2 would work: 12V@18A = 216W... but the plug itself has a max 12V@1A :-/. So a cheap 12V@5A brick might be enough for the total wattage (including the 5V rail).

The sustained power levels are listed as:

      5V: 4.5A
     12V: 1.0A
    -12V: 0.1A

I get 44.5+121+12*0.1=35.7 W from that, but then there has to be some losses too in that 5 V-regulation, but 60 W is probably a bit extreme. No idea how much power an Amiga consumes, though ... found [1] which states 35.7 W (hm) or 25.7 W so it seems to be aiming for the higher of the two which of course makes sense. The A600 and A1200 need even less, max 22.2 W for both models.

[1]: http://www.ianstedman.co.uk/amiga-power-supply-guide/

I did more or less the same calculation when I arrived at 60 W, but with the peak power levels - if a PSU isn't able to deliver the peak current, which is probably needed when the computer boots up (with the HD spinning up etc.), I'm afraid it won't get to the "sustained" phase...

Most amigas users are using some kind of solid state storage these days which will ameliorate this a little. But many/most are using assorted expansion and accelerator cards which can substantially increase the power draw.

It's a bit if a moveable feast how much power an amiga is drawing these days. Certainly, back in the 90s, the original a1200 power supplies often needed to be replaced with something that could deliver more, and the a500 supplies were favoured

Many Amigas also have a Raspberry Pi inside them these days, for the PiStorm accelerator, which increases the +5V current requirements a fair bit.

Is the pi usually on it's own power supply?

Not with the PiStorm32 Lite that I've got.

Seemed to run OK with a Pi 4 on an original Commodore PSU, or at least nothing appears to have blown up or melted when running it for short periods.

Maybe I'm pushing my luck, but then again, back in the day, you'd often be running an accelerator board, hard drive, and a couple of floppy drives from that same PSU, so maybe it's up to the job.

It might also be a way to indicate that you can't just use a USB A-to-C "charging" cable, and connect it to an old-school 5 V-only USB adapter. It needs the modern power-delivery things which are only available over USB C.

There was (that I could find, and I did go back to check again) no mention of price other than "TBD", which probably means it's not aiming to be a cheap solution. Trying to guesstimate but it's hard, I'm not enough "into" the Amiga retro scene. $99 feels like too much ... $79?

Finally, I found the copy on the site a couple of generous notches above 10 and really think it would help to tone it down just a little. But maybe that's just me being grouchy, as someone who grew up on Amigas it's really great to see this kind of development and continued interest in the machines! Good luck!

From what I heard from people who are involved in the development and/or in betatesting, the target price is indeed around 80€, so your estimate is pretty spot on

Invest in a STM32G0 Discovery Kit for about $60. It tells you exactly what your USB-C power cube is capable of putting out.

So far I've only found one 35W Samsung cube that meet the spec of putting out 3.1V to 21V.

Most only put out one or two of the voltages of 9V, 12V, 15V or 21V. The 15W and under are usual 9V or 12V, with one being 15V. All will always default to 5V.

https://www.st.com/content/ccc/resource/technical/document/d...

And watch out for weird pseudo-USB-C chargers. I’ve read about some cheap power tools being sold with “USB-C charging”. But they merely used the plug as a selling point. The AC adapter was a bog standard one and always sent 12V to the USB-C plug. So you’d fry any normal USB-C device you plug this into.

USB devices built according to the spec must have overvoltage protection, but yeah, I'd be surprised if all of them actually implemented it.

This is awesome, especially since Commodore power supplies do have a reputation for not being the best quality ones. This is more of an issue on the Commodore 64 where you should NEVER use the original power supply anymore because it's playing russian roulette. I'm not sure if the Amiga 500 power supplies were equally prone to frying your system and I'm hoping that by 1992 they got it sorted out, but still, better be safe than sorry and not risk anything.

As I understand it the issue is that when the old c64 power supplies failed the 12v line would go overvoltage and fry your computer. The amiga power supplies are designed differently and don't have this "feature".

Though it is often worth replacing the original amiga power supplies as the capacitors are often shot by this point

There is no 12V input to C64, just 5VDC and 9VAC. You are thinking about 5V supply, which indeed fried many computers when the PSU failed and ramped the voltage up.

When I used to power my Amiga 1200 with an ATX power supply, you could power it "in reverse" by _supplying_ +12V and +5V to the floppy disk power connector on the motherboard. But for proper operation, you also needed -12V, and that had to come from the ATX motherboard plug and go into middle hole of the Amiga's power socket.

Could any electrical engineers here explain how one gets both +12V and -12V output from a +12V input?

-12V is to make the strong zeroes. Hardened voids are a forgotten art in this age of USB-positive softness.

I think you may have a strong future in the audiophile selling business. :)

Without the -12V, the silent sections in the music just isn't as airy.

Believe it or not, the -12V is used for the audio! Maybe not the GP's technobabble.

http://www.ianstedman.co.uk/amiga-power-supply-guide/

> What is the -12V supply on the Amiga used for?

> It is used for the RS232 transceiver chips and to power the Op-Amps in the audio circuits.

So the Amiga's audio just won't have that oomph without that -12V power.

Blue pin on the ATX motherboard plug is -12V.

I assume the PSU isn't making -12V from +12V. It's making both of them from whatever the AC is

I assume AC is even easier, but in DC, splitting a 24V supply into 12V and -12V is trivial.

Voltage is just your distance from ground, and while we generally think ground has 0 volts, really it can have any number of volts, just whatever circuit you're running is higher. Voltage is relative to the ground potential.

To put it another way, voltage is pressure in flowing water. If you pick a river as "earth" 12V is whatever 12V is in speed faster than the flow of the river, and -12V is going the same amount slower than the river. The river is your ground potential

You can read the theory of operation for generating negative voltage in this application note from Analog Devices: https://www.analog.com/en/resources/design-notes/generating-...

You boost it to 24V and then use 12V as GND, 24V as +12V and actual GND of supply as -12V.

This is going to be a simple yet very convenient piece of hardware.

Question is whether it will be able to run Amigas with accelerators inside? That usually required beefier 6A PSU

Apparently they demoed it on Amiga38, powering an A1200 with a '040 accelerator and/or PiStorm card, card and that was no problem. I have not seen nor done the actual maths, but since it's done by actual Amiga community people and not some shady Chinese company, I would say it's safe to assume they considered these use cases.

Hopefully, Blizzard 1260 has ability to turn itself into an oven real fast.

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