Author Topic: Easy PicoPSU  (Read 925 times)

Offline mattsoft

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Easy PicoPSU
« on: October 01, 2018, 03:59:09 AM »
Hi all - my recently acquired X68000 ACE had a dead PSU that I tried to resurrect with new caps and zeners with no luck. So I bought an AC-DC adapter and PicoPSU and wired it up with success -- but I hate the messy bundle of cables and would like a more finished look that uses the ACE's PSU cage.

I saw this blog: https://m.blog.naver.com/PostView.nhn?blogId=iolokim&logNo=221075411751&proxyReferer=https%3A%2F%2Fwww.google.com%2F -- but cannot find that adapter board available in the U.S. So...I'm using it as a reference and building my own. Attached is a very early preview of the board with just the soft power + inverter plotted. I hope to have samples of the board in November and if it works, I will make the schematics available for free.

If someone else has already done this, please holler!

Offline leonk

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Re: Easy PicoPSU
« Reply #1 on: October 01, 2018, 02:04:50 PM »
i look forward to this pcb. if you offer the gurbers for free it will go a long way to preserving the x68k for years to come; long after any of us leave this hobby. All your hard work will not be lost.

just a thought.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #2 on: October 03, 2018, 12:30:08 PM »
If it works, the gerbers will be free. I'll probably even have some spare from manufacturing mine to sell at cost.

Progress made. Switched CAD software to KiCad and have completed the first drawing. I want to double-check all the traces including weight and width, and plot the mount holes in the corners. I'm planning on 6-8 amps for the +5, -12, and +12 routes which is probably overkill. I may also add a jumper to bypass the soft power on in case you need to troubleshoot that functionality of your X68000 (like I have had to do). I'm a noob at this, so...

3d renders attached. * whoops, the +12V on the right side is mislabeled -- it's actually a 3rd +5V. :)
« Last Edit: October 03, 2018, 12:38:43 PM by mattsoft »

Offline mattsoft

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Re: Easy PicoPSU
« Reply #3 on: October 05, 2018, 08:30:22 AM »
Prototype ordered...should have first build soldered up for testing in a couple of weeks.

Offline gypsie

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Re: Easy PicoPSU
« Reply #4 on: October 05, 2018, 09:20:40 PM »
Very good mattsoft! 8)

Offline Jehuty

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Re: Easy PicoPSU
« Reply #5 on: October 10, 2018, 03:04:38 AM »
Nice Work. Like to get one PCb or Files to get one. Thanks.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #6 on: October 11, 2018, 02:18:58 AM »
the prototype boards have shipped! there are 10. assuming they work and I don't destroy any in my testing, i should have around 8 left available. the cost will be USD$5 per unpopulated board + shipping which is basically my cost. i'll also post the gerbers and BOM on GitHub if you want to improve the design or make your own. this is all assuming they work!

Offline leonk

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Re: Easy PicoPSU
« Reply #7 on: October 11, 2018, 05:09:49 AM »
If it works.. I'll take 1.

Offline ShootTheCore

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Re: Easy PicoPSU
« Reply #8 on: October 11, 2018, 08:57:12 AM »
I'm interested in one too.

Offline gypsie

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Re: Easy PicoPSU
« Reply #9 on: October 14, 2018, 03:24:35 AM »
me too :)

Offline rkrenicki

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Re: Easy PicoPSU
« Reply #10 on: October 14, 2018, 05:55:11 AM »
I ran into the same issue with my ProII power supply.  I replaced all of the caps, zeners, 5 transistors, several resistors, and the optoisolators and even the T2 transformer.. with no luck at all.  I think one of the replacement transistors is bad, but I just got too frustrated with it and decided to go the ATX route.    I literally just got the machine to boot with an adapter cable that I made up, but I would like a more polished product for sure.

Count me in for one, Thanks!

EDIT:  Can you tell me the overall dimensions of the adapter?  I am wondering if it along with the PicoPSU itself would fit within the stock power supply case.. 
« Last Edit: October 14, 2018, 11:58:58 AM by rkrenicki »

Offline mattsoft

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Re: Easy PicoPSU
« Reply #11 on: October 15, 2018, 03:13:58 AM »
I ran into the same issue with my ProII power supply.  I replaced all of the caps, zeners, 5 transistors, several resistors, and the optoisolators and even the T2 transformer.. with no luck at all.  I think one of the replacement transistors is bad, but I just got too frustrated with it and decided to go the ATX route.    I literally just got the machine to boot with an adapter cable that I made up, but I would like a more polished product for sure.

Count me in for one, Thanks!

EDIT:  Can you tell me the overall dimensions of the adapter?  I am wondering if it along with the PicoPSU itself would fit within the stock power supply case..

its 61mmx94mm and designed to fit in the original case with the PicoPSU in front of the fan. the mounting holes are positioned correctly to screw right in. i haven't quite figured out the rest yet, but i plan to put the pico's DC in jack in place of the AC input. i will have the test boards completed this week and will post pictures and results.

Offline hoshikawa

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Re: Easy PicoPSU
« Reply #12 on: October 15, 2018, 11:04:16 AM »
I've had success removing the FG ground terminal and installing the DC in jack there, it looks really clean from the back. I tried putting it in the AC in hole but it just doesn't look right imo.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #13 on: October 16, 2018, 12:39:07 PM »
Soldered up and the board works. Mostly. Like a dumbass, I failed to wire up pin 7 of the inverter to ground. Doh! I ran a test wire from pin 7 to ground and the adapter works perfectly! Success! My ACE boots from soft power and floppy.

So...I am going to fix this in the design and make a couple other small changes and then get final boards made and publish the gerbers and BOM.

In the meantime, I have 10 of these boards available. Because of the design flaw, I’m offering them free + the price of shipping. I can include a digikey BOM too. U will need to run a wire to ground the inverter. Even with this flaw, it makes a tidy Pico conversion and gets rid of any cable rats nest. PM me if u want a board and how many u want. Fixed boards will be another 3-4 weeks out.
« Last Edit: October 16, 2018, 04:34:03 PM by mattsoft »

Offline ShootTheCore

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Re: Easy PicoPSU
« Reply #14 on: October 17, 2018, 09:44:39 AM »
I don't mind running a ground wire.  PM sent.

Offline kamiboy

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Re: Easy PicoPSU
« Reply #15 on: October 17, 2018, 10:05:53 PM »
With all that free space left inside the PSU case I am sure you could even find room for the whole power adapter inside there. I am sure that if you remove the plastic shell of that thing it will take up even less room.

Luckily all my original PSU's work, but if I had to do something like this I would prefer to have one cable coming out of my machine that plugs directly into the wall.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #16 on: October 18, 2018, 02:24:45 AM »
With all that free space left inside the PSU case I am sure you could even find room for the whole power adapter inside there. I am sure that if you remove the plastic shell of that thing it will take up even less room.

Luckily all my original PSU's work, but if I had to do something like this I would prefer to have one cable coming out of my machine that plugs directly into the wall.

That is my next goal.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #17 on: October 18, 2018, 05:35:00 AM »
Project is on GitHub: https://github.com/mattsoft/X68K_EZ_Pico_PSU

If you'd like to clone and modify for your own use, go for it! I'd love changes by way of pull requests too. If you have questions, let me know. Have fun!

Offline vanpeebles

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Re: Easy PicoPSU
« Reply #18 on: October 18, 2018, 06:31:15 PM »
Please put me down for a fixed one :)

Offline hyrulebr

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Re: Easy PicoPSU
« Reply #19 on: October 18, 2018, 11:39:49 PM »
Congrats Matt! Nice project!  :)

I´m also interest in one mounted board if you plan to sell some.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #20 on: October 23, 2018, 03:48:53 AM »
I've decided to change v2 of this board and bring the AC-DC converter INSIDE.


Offline mattsoft

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Re: Easy PicoPSU
« Reply #21 on: November 11, 2018, 11:57:18 AM »
V2 board with integrated AC-DC adapter has been ordered! More soon...

Offline leonk

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Re: Easy PicoPSU
« Reply #22 on: November 11, 2018, 04:49:31 PM »
what is the advantage of doing v2? easier to find external AC?

Offline mattsoft

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Re: Easy PicoPSU
« Reply #23 on: November 11, 2018, 06:28:08 PM »
The only advantage is that it will be 100% internal so it will look stock -- no need for external PSU.

Offline leonk

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Re: Easy PicoPSU
« Reply #24 on: November 12, 2018, 04:19:49 PM »
with rev2 it will run on mains? 120/220V AC?

Offline mattsoft

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Re: Easy PicoPSU
« Reply #25 on: November 13, 2018, 01:43:39 AM »
with rev2 it will run on mains? 120/220V AC?

Yep. As soon as I have the boards I will post a build.

Offline neko68k

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Re: Easy PicoPSU
« Reply #26 on: November 13, 2018, 04:51:17 AM »
nice work, man <3

Offline kamiboy

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Re: Easy PicoPSU
« Reply #27 on: November 13, 2018, 05:18:26 PM »
Now this is looking like an ideal solution. All internal, direct from machine to wall socket is how it should be.

Offline leonk

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Re: Easy PicoPSU
« Reply #28 on: November 14, 2018, 05:00:00 AM »
I have a microATX PSU in my OG X68K; so I have an all internal solution.  But even though it's a MicroATX PSU, there are a lot of components there to make sure power is clean, safe, with over voltage, over heating, etc. protection all there.  Designing a Power Supply is not a simple task.

So the choice of components that make up this PicoPSU adapter can either make it or break.

Looking forward to see the solution.

Offline mattsoft

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Re: Easy PicoPSU
« Reply #29 on: November 14, 2018, 06:39:05 AM »
I have a microATX PSU in my OG X68K; so I have an all internal solution.  But even though it's a MicroATX PSU, there are a lot of components there to make sure power is clean, safe, with over voltage, over heating, etc. protection all there.  Designing a Power Supply is not a simple task.

So the choice of components that make up this PicoPSU adapter can either make it or break.

Looking forward to see the solution.

Yeah, and I'm self admittedly an amateur so...

I'm using this AC-DC converter: https://www.digikey.com/product-detail/en/bel-power-solutions/ABC75-1T12L/179-2836-ND/5629042 to provide 12VDC. It has over-heat shutdown protection and runs pretty efficiently. I'll be curious to see how warm it gets with the fan blowing air directly over it. I used various published sources to determine realistic power usage of an ACE running < 4MB, dual floppy, and HDD, and it came in WELL under 75W for continuous operation, and was under 75W at power-on time. If you have a bunch of add-ons, 75W might be tight. There is a 95W option as well but would cost more all around.

It will also use a PicoPSU to take the 12VDC from the AC-DC converter and provides 12VDC and 5VDC (along with power-on and stand-by 5VDC) to the X68000. The PicoPSU provides over voltage protection to the components downstream.

So I think it will work great pretty well as long as it stays cool.