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NFGGames.com => SIG X68000 => Topic started by: mattsoft on October 01, 2018, 03:59:09 am

Title: Easy PicoPSU
Post by: mattsoft 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!
Title: Re: Easy PicoPSU
Post by: leonk 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.
Title: Re: Easy PicoPSU
Post by: mattsoft 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. :)
Title: Re: Easy PicoPSU
Post by: mattsoft on October 05, 2018, 08:30:22 am
Prototype ordered...should have first build soldered up for testing in a couple of weeks.
Title: Re: Easy PicoPSU
Post by: gypsie on October 05, 2018, 09:20:40 pm
Very good mattsoft! 8)
Title: Re: Easy PicoPSU
Post by: Jehuty on October 10, 2018, 03:04:38 am
Nice Work. Like to get one PCb or Files to get one. Thanks.
Title: Re: Easy PicoPSU
Post by: mattsoft 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!
Title: Re: Easy PicoPSU
Post by: leonk on October 11, 2018, 05:09:49 am
If it works.. I'll take 1.
Title: Re: Easy PicoPSU
Post by: ShootTheCore on October 11, 2018, 08:57:12 am
I'm interested in one too.
Title: Re: Easy PicoPSU
Post by: gypsie on October 14, 2018, 03:24:35 am
me too :)
Title: Re: Easy PicoPSU
Post by: rkrenicki 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.. 
Title: Re: Easy PicoPSU
Post by: mattsoft on October 15, 2018, 03:13:58 am
Quote from: rkrenicki 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..


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.
Title: Re: Easy PicoPSU
Post by: hoshikawa 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.
Title: Re: Easy PicoPSU
Post by: mattsoft 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.
Title: Re: Easy PicoPSU
Post by: ShootTheCore on October 17, 2018, 09:44:39 am
I don't mind running a ground wire.  PM sent.
Title: Re: Easy PicoPSU
Post by: kamiboy 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.
Title: Re: Easy PicoPSU
Post by: mattsoft on October 18, 2018, 02:24:45 am
Quote from: kamiboy 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.


That is my next goal.
Title: Re: Easy PicoPSU
Post by: mattsoft 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!
Title: Re: Easy PicoPSU
Post by: vanpeebles on October 18, 2018, 06:31:15 pm
Please put me down for a fixed one :)
Title: Re: Easy PicoPSU
Post by: hyrulebr 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.
Title: Re: Easy PicoPSU
Post by: mattsoft on October 23, 2018, 03:48:53 am
I've decided to change v2 of this board and bring the AC-DC converter INSIDE.

Title: Re: Easy PicoPSU
Post by: mattsoft on November 11, 2018, 11:57:18 am
V2 board with integrated AC-DC adapter has been ordered! More soon...
Title: Re: Easy PicoPSU
Post by: leonk on November 11, 2018, 04:49:31 pm
what is the advantage of doing v2? easier to find external AC?
Title: Re: Easy PicoPSU
Post by: mattsoft 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.
Title: Re: Easy PicoPSU
Post by: leonk on November 12, 2018, 04:19:49 pm
with rev2 it will run on mains? 120/220V AC?
Title: Re: Easy PicoPSU
Post by: mattsoft on November 13, 2018, 01:43:39 am
Quote from: leonk on November 12, 2018, 04:19:49 pm
with rev2 it will run on mains? 120/220V AC?


Yep. As soon as I have the boards I will post a build.
Title: Re: Easy PicoPSU
Post by: neko68k on November 13, 2018, 04:51:17 am
nice work, man <3
Title: Re: Easy PicoPSU
Post by: kamiboy 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.
Title: Re: Easy PicoPSU
Post by: leonk 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.
Title: Re: Easy PicoPSU
Post by: mattsoft on November 14, 2018, 06:39:05 am
Quote from: leonk 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.


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.
Title: Re: Easy PicoPSU
Post by: X-Col on November 20, 2018, 11:38:26 pm
Hi Matt,

I got round to populating one of the version 1 boards you sent me and trying it on my ACE.

I have 2 PICO PSU's and here are the results:
The 'bootleg' PICO does not turn on when the power switch is pressed (continuous red light)
The genuine PICO 120 will not turn off - with button in the off position the system seems to go into a shutdown loop (no red light)

However, it works perfectly with a genuine ATX PSU!  :o

Any ideas?  ???
Title: Re: Easy PicoPSU
Post by: mattsoft on November 21, 2018, 03:45:06 am
Quote from: X-Col on November 20, 2018, 11:38:26 pm
Hi Matt,

I got round to populating one of the version 1 boards you sent me and trying it on my ACE.

I have 2 PICO PSU's and here are the results:
The 'bootleg' PICO does not turn on when the power switch is pressed (continuous red light)
The genuine PICO 120 will not turn off - with button in the off position the system seems to go into a shutdown loop (no red light)

However, it works perfectly with a genuine ATX PSU!  :o

Any ideas?  ???


Weird. And just to confirm, your ATX PSU is plugged into the PCB in place of the PicoPSU? If so, then the inverter chip circuit is correct, but something about your PicoPSU is different. I'll do some more research and see if there are differences between PicoPSUs.
Title: Re: Easy PicoPSU
Post by: X-Col on November 21, 2018, 03:58:16 am
Quote from: mattsoft on November 21, 2018, 03:45:06 am
Weird. And just to confirm, your ATX PSU is plugged into the PCB in place of the PicoPSU? If so, then the inverter chip circuit is correct, but something about your PicoPSU is different. I'll do some more research and see if there are differences between PicoPSUs.


Yeh, I just plugged in the ATX PSU into the connector where the PicoPSU was and it worked fine. Strange that both my Pico's exhibit different behaviours  :o

The one that won't turn off is this one: (PicoPSU-120 (RS) 120w output) https://www.ebay.co.uk/itm/PicoPSU-120-RS-120w-output-12v-input-DC-DC-Power-Supply/263572842034?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
The other one is the original Pico I was using before I installed this board. It used to work fine, but now won't turn on.  ???

Strange indeed!
Title: Re: Easy PicoPSU
Post by: mattsoft on November 21, 2018, 06:58:23 am
Found this during my lunch hour today: https://www.colonel-panic.org/PicoPSU/

The 4.7k ohm resistor on the PCB should be doing this but maybe 4.7k isn't enough resistance? maybe try a 10k ohm?
Title: Re: Easy PicoPSU
Post by: elmer on December 05, 2018, 05:36:43 pm
mattsoft: You can definitely put me down for one of these, if you have any extras to sell ... it would be lovely to finally get my X68000 to turn on after all of the years that I've owned it.
Title: Re: Easy PicoPSU
Post by: mattsoft on December 07, 2018, 10:08:39 am
Just a status update -- this has been temporarily sidelined by the fact that my ACE is no longer working and I'm spending time trying to get it working again. :(
Title: Re: Easy PicoPSU
Post by: X-Col on December 09, 2018, 10:07:11 pm
Sorry to hear that Matt, hope you figure it out!  :o

These machines are a lesson in S&M; still have issues with sound 'cracking' on my Compact and my ACE refuses to play nicely with PicoPSU's....  :(
Title: Re: Easy PicoPSU
Post by: leonk on December 10, 2018, 03:45:53 pm
From all the electronics repair I’ve done over the years, nothing has kicked me harder than an X68k. When you’re down, it just keeps on kicking. ;)
Title: Re: Easy PicoPSU
Post by: mattsoft on December 11, 2018, 02:34:43 am
Quote from: leonk on December 10, 2018, 03:45:53 pm
From all the electronics repair I’ve done over the years, nothing has kicked me harder than an X68k. When you’re down, it just keeps on kicking. ;)


Yup. I've got the bruises and broken ribs to prove this.

Got 2 more X68000 ACE's coming in from YAP for spare parts. Hoping to have enough to get this baby up and running again.

Or maybe I'm just pouring money down the drain. ;)
Title: Re: Easy PicoPSU
Post by: X-Col on December 13, 2018, 05:03:35 am
@mattsoft

Just to let you know that another PicoPSU arrived today and it works nicely with the X68000!!

Fitted your version 1 board today and all is good  ;D

Thank you, and hope you find the problem with yours!
Title: Re: Easy PicoPSU
Post by: X-Col on December 13, 2018, 05:19:27 am
Here is how the rear of the ACE looks, pretty near stock. And the on/off switch on the PSU works  ;)
Title: Re: Easy PicoPSU
Post by: mattsoft on December 13, 2018, 05:59:21 am
Quote from: X-Col on December 13, 2018, 05:03:35 am
@mattsoft

Just to let you know that another PicoPSU arrived today and it works nicely with the X68000!!

Fitted your version 1 board today and all is good  ;D

Thank you, and hope you find the problem with yours!


Nice! So the shutdown issue was perhaps PicoPSU-brand related?
Title: Re: Easy PicoPSU
Post by: X-Col on December 13, 2018, 06:09:09 am
Quote from: mattsoft on December 13, 2018, 05:59:21 am
Nice! So the shutdown issue was perhaps PicoPSU-brand related?


I would assume so,  I now have 3 PicoPSU's and only 1 of them works with the X68000. All 3 of them work fine in a PC.
It seems it's a bit of a lottery if a Pico will work with the system shutdown/startup circuit of the X68000  ???
Title: Re: Easy PicoPSU
Post by: leonk on December 14, 2018, 05:21:19 pm
Any progress on the Easy PicoPSU complete solution? I just got an XVI HD in, and the "lego" piece power supply is shot.  Everything is black in there, fuse popped.. what a disaster.  Looking for new PSU solution.
Title: Re: Easy PicoPSU
Post by: mattsoft on December 15, 2018, 01:56:56 am
Quote from: leonk on December 14, 2018, 05:21:19 pm
Any progress on the Easy PicoPSU complete solution? I just got an XVI HD in, and the "lego" piece power supply is shot.  Everything is black in there, fuse popped.. what a disaster.  Looking for new PSU solution.


i have all the parts, but have been sidelined by my ACE deciding it doesn't want to work anymore so I've been focusing on trying to get it working. I'll get back to it over the holiday break.
Title: Re: Easy PicoPSU
Post by: leonk on December 26, 2018, 02:22:30 pm
I just want to say that this device worked great for me in restoring an XVI. I did notice that 3 5V pins on the pico ATX connector aren’t connected but that should be fine and there are enough 5V sources.

I did find a strange issue with one of my connected FD. It doesn’t work. The 5V line is only abou 3.5V. The other 5V lines around the system are at 4.95V. I wonder if there’s something wrong with this FD that pulls the 5V rail down hard. I replaced all the caps. Hmmmm
Title: Re: Easy PicoPSU
Post by: mattsoft on December 27, 2018, 03:17:30 am
Quote from: leonk on December 26, 2018, 02:22:30 pm
I just want to say that this device worked great for me in restoring an XVI. I did notice that 3 5V pins on the pico ATX connector aren’t connected but that should be fine and there are enough 5V sources.

I did find a strange issue with one of my connected FD. It doesn’t work. The 5V line is only abou 3.5V. The other 5V lines around the system are at 4.95V. I wonder if there’s something wrong with this FD that pulls the 5V rail down hard. I replaced all the caps. Hmmmm


There are 4 +5VDC rails on the PicoPSU. I am using 3 of the 4 for this project; they're on the bottom of the board. Make sure you are using a REAL PicoPSU and not an aftermarket unit -- the voltages on those knockoffs can be whacky!
Title: Re: Easy PicoPSU
Post by: mattsoft on December 27, 2018, 03:19:38 am
New PCB with onboard AC-DC to be tested this weekend. This aims to be an all-in-one internal replacement for the lego brick PSU. Preview of board attached. If this works OK, I'll post the gerbers and BOM to GitHub.
Title: Re: Easy PicoPSU
Post by: leonk on December 27, 2018, 04:57:00 am
I'm using the real PicoPSU from short-circuit.com, the 120 Watt version.
Title: Re: Easy PicoPSU
Post by: leonk on December 27, 2018, 04:57:52 am
Quote from: mattsoft on December 27, 2018, 03:19:38 am
New PCB with onboard AC-DC to be tested this weekend. This aims to be an all-in-one internal replacement for the lego brick PSU. Preview of board attached. If this works OK, I'll post the gerbers and BOM to GitHub.


Can you post pics of underside as well?  I want to confirm the traces.

Also, for your latest design, one should know they need to choose one or the other, not both!  (i.e. use PicoPSU or AC/DC converter)  :)

Title: Re: Easy PicoPSU
Post by: mattsoft on December 27, 2018, 07:15:44 am
Quote from: leonk on December 27, 2018, 04:57:52 am
Quote from: mattsoft on December 27, 2018, 03:19:38 am
New PCB with onboard AC-DC to be tested this weekend. This aims to be an all-in-one internal replacement for the lego brick PSU. Preview of board attached. If this works OK, I'll post the gerbers and BOM to GitHub.


Can you post pics of underside as well?  I want to confirm the traces.

Also, for your latest design, one should know they need to choose one or the other, not both!  (i.e. use PicoPSU or AC/DC converter)  :)


Bottom attached.

The all-in-one will require an AC-DC converter + PicoPSU to condition the power and provide the various voltages (+ SB). It's inspired by the work user Arcade did in this thread: https://nfggames.com/forum2/index.php?topic=5542.0
Title: Re: Easy PicoPSU
Post by: leonk on December 27, 2018, 08:03:55 am
Oh.. right.  my mistake.  Rather than using an external 12V power source, you are using it as all internal.  In this case, what's not seen, is the 12V + GND wires for the PicoPSU will not come from the barrel style connector, but rather jump in from the AC/DC internal PSU.  The internal PSU will then get it's AC in from the stock connector / after the power switch.  Very nice. 

I think it would still be safe to keep the internal fan off as the AC/DC converter will be switching type which has very high efficiency with minimal heat generation (unlike the more traditional linear supplies that dissipate a lot of heat)
Title: Re: Easy PicoPSU
Post by: mattsoft on December 27, 2018, 08:17:44 am
Quote from: leonk on December 27, 2018, 08:03:55 am
Oh.. right.  my mistake.  Rather than using an external 12V power source, you are using it as all internal.  In this case, what's not seen, is the 12V + GND wires for the PicoPSU will not come from the barrel style connector, but rather jump in from the AC/DC internal PSU.  The internal PSU will then get it's AC in from the stock connector / after the power switch.  Very nice. 

I think it would still be safe to keep the internal fan off as the AC/DC converter will be switching type which has very high efficiency with minimal heat generation (unlike the more traditional linear supplies that dissipate a lot of heat)


Yeah, the AC will run direct to the AC-DC converter and the 12VDC will come from the AC-DC converter into the PicoPSU (via wires). Should be pretty slick.

When it's done, I'll send you a couple of boards to play with. I'm open to ideas to improve it -- for example, putting in a more powerful AC-DC/PicoPSU.
Title: Re: Easy PicoPSU
Post by: leonk on December 29, 2018, 02:45:37 am
I was thinking about this solution, and realized what has been bugging me.. the missing ground!

In Japan (or at least when these computers were made) all outlets were 2 prong 100V / 60hz AC.  Hence all electric devices were only 2 prong.  Reference ground for computers is very important, hence why the ground posts were added (and used!).  A lot of these old power supplies also use a simple transformer to step down the voltage.. so which pin gets 100V AC vs Neutral isn't that important.

On the other hand, the modern AC/DC 12V switching power supply you want to use requires a proper ground (to reference against in order for the over voltage and other protections to work correctly).  I'm also not too sure about what will happen if you feed 110V AC into ground pin.. I suspect not a good thing.

This is why, when I put a modern power supply into my OG X68000, I replaced the power cord on my X68000 with a 3 prong one.  This way, I know for sure what is AC, Neutral and ground.

As for your original solution, it worked great because the external 12V 10A power supply is properly grounded and has all the required fuses/safeties in place.



Title: Re: Easy PicoPSU
Post by: mattsoft on December 29, 2018, 05:23:17 pm
Quote from: leonk on December 29, 2018, 02:45:37 am
I was thinking about this solution, and realized what has been bugging me.. the missing ground!

In Japan (or at least when these computers were made) all outlets were 2 prong 100V / 60hz AC.  Hence all electric devices were only 2 prong.  Reference ground for computers is very important, hence why the ground posts were added (and used!).  A lot of these old power supplies also use a simple transformer to step down the voltage.. so which pin gets 100V AC vs Neutral isn't that important.

On the other hand, the modern AC/DC 12V switching power supply you want to use requires a proper ground (to reference against in order for the over voltage and other protections to work correctly).  I'm also not too sure about what will happen if you feed 110V AC into ground pin.. I suspect not a good thing.

This is why, when I put a modern power supply into my OG X68000, I replaced the power cord on my X68000 with a 3 prong one.  This way, I know for sure what is AC, Neutral and ground.

As for your original solution, it worked great because the external 12V 10A power supply is properly grounded and has all the required fuses/safeties in place.


Yeah, that is a good idea. This new solution does tie the ground of the AC-DC into the PicoPSU on the board but that is obviously worthless if the whole thing isn't tied into a real Earth ground. The missing piece is if you use the original power cord to the AC-DC mains terminal -- it is missing ground like you say. When I build this new one, I will use a 3-wire power cord with proper neutral, hot, and ground, and wire that into the AC-DC mains terminal.
Title: Re: Easy PicoPSU
Post by: leonk on January 06, 2019, 04:23:19 pm
If you use a pico PSU (or ATX psu for that matter) don’t power everything off the ATX connector. You’ll run into weird power issues (like power button not working). The connector can not supply enough current for the entire computer. I suggest plugging the floppy drives into the 4 pin moldex that’s plugged into the picoPSU. You’ll avoid a low voltage situation that the X68k will detect and cause issues.
Title: Re: Easy PicoPSU
Post by: mattsoft on January 08, 2019, 02:25:31 pm
Some very minor progress. Hah! Boards finally arrived, AC-DC converter fitted, board fits in metal PSU case perfect. Hopefully solder and test tomorrow night.
Title: Re: Easy PicoPSU
Post by: mattsoft on January 10, 2019, 03:17:57 am
First board is built and voltage and soft power tests are good. Hot/neutral polarity on the AC matters with this AC-DC converter it seems. If I reverse hot/neutral into the AC-DC converter, it seems that the soft power does not function and it forces the PicoPSU on. So I need to first do a little more testing and verify this and then just to be safe, I'm going to source a proper 3-pronged AC power cable that fits nicely and allows me (a) ground the damn thing and (b) guarantee hot is hot and neutral is neutral from mains to AC-DC to before doing any more tests. It does all fit inside the original metal case though, even with the fan hooked up. It's definitely very clean.
Title: Re: Easy PicoPSU
Post by: leonk on January 10, 2019, 03:38:38 am
I want to reiterate an import finding I've made with both the OG X6800 running a PC ATX PSU as well as PicoPSU on the XVI HD.

Do not power the floppy drives from the ATX connector.  Even when PicoPSU is used inside a standard PC, it's not designed for that.  That's why breakout cables are provided on the PicoPSU to power drives (floppy, CD-ROM, Hard Drives, etc.)  The ATX connector can not reliably provide enough current for both the computer as well as FDD's.

Title: Re: Easy PicoPSU
Post by: mattsoft on January 10, 2019, 04:13:09 am
Quote from: leonk on January 10, 2019, 03:38:38 am
I want to reiterate an import finding I've made with both the OG X6800 running a PC ATX PSU as well as PicoPSU on the XVI HD.

Do not power the floppy drives from the ATX connector.  Even when PicoPSU is used inside a standard PC, it's not designed for that.  That's why breakout cables are provided on the PicoPSU to power drives (floppy, CD-ROM, Hard Drives, etc.)  The ATX connector can not reliably provide enough current for both the computer as well as FDD's.


when i get this thing done and posted to GitHub, i'll include that in the readme. it's really easy to just connect the FDD leads to the 4-pin MOLEX on the PicoPSU.

in a future redesign, it might be interesting to run the 4-pin MOLEX from the PicoPSU to the board and break-out the +5VDC & +12VDC from the MOLEX to FDD headers on the board.
Title: Re: Easy PicoPSU
Post by: leonk on January 10, 2019, 06:43:35 am
That will be handy if you don't want to do any soldering at all.  I ended up soldering a female 4 pin molex connector on my FDD power cable (you know, the yellow/black/black/red 5.25" connector).  This female connector then plugs into the male plug that comes out of the picoPSU.

If you do go down that route, make sure ground also comes from this connector.  I think the problem might stem with the wire gauge .. only so much current can go down a given wire.  Maybe that's why there are 2 ground wires.
Title: Re: Easy PicoPSU
Post by: mattsoft on January 14, 2019, 10:41:08 am
Another small update...

I have the PicoPSU v2 wired up and tested good. Per @leonk's suggestion, I wired in a 3-prong grounded cable which grounds the entire assembly and electrical system of the X68000. Had to 3D print a cable relief to the metal PSU box. With it all screwed together it looks close to stock!

Unfortunately, I cannot find the 4-pin JST cable for my PicoPSU to hook up to the FDD lead (again, per @leonk's suggestion). UGH! Will need to order new one.

v3 of this design will definitely simplify the wiring by running the PicoPSU 4-pin JST to a header on the PCB that explicitly powers the FDD.

Now if I can get some time, I'll get this posted to my GitHub for others to play with. I have spare boards if anyone wants one.
Title: Re: Easy PicoPSU
Post by: leonk on January 14, 2019, 02:40:53 pm
Thank you for all your effort. If I was to rebuild an x68k today I wouldn’t think twice about using your wonderful design.

Title: Re: Easy PicoPSU
Post by: TD-Linux on January 16, 2019, 02:18:41 pm
I did a very similar PSU mod, with the exception that I didn't make a PCB - a 3D printed plate holds the PicoPSU and open frame supply in place.

One problem I've been having is that after about an hour, the machine starts resetting. I basically see a fast square wave on the picopsu's 12V line. Oddly, the problem goes away if I disconnect the -12V line. Have you had any similar problems?
Title: Re: Easy PicoPSU
Post by: leonk on January 17, 2019, 07:02:46 am
Sounds to me like a defective PicoPSU / not real one / clone.

I had no issues with my PicoPSU.
Title: Re: Easy PicoPSU
Post by: TD-Linux on January 17, 2019, 06:51:11 pm
Turns out it's not the PSU's fault, I can reproduce the same problem by applying -12V with a bench supply. Sorry for the noise, I'll move to a separate thread if I figure it out.

EDIT: it was actually me forgetting to add a pullup to the x86000's PSU CTRL line. Despite being reverse polarity to ATX, it's still open collector. Without a pullup, it will slowly float high, but you'll get tons of weird behavior, such as the neighboring -12V line coupling in. Remember the resistor!
Title: Re: Easy PicoPSU
Post by: amigo-mexicano on January 22, 2019, 08:48:28 am
What a cool project! Been reading all day long about it. Congrats mattsoft, and thanks for sharing!

Now, this says it's for the ACE, but should work for any model, right? I want to use it on a SUPER... :)
Title: Re: Easy PicoPSU
Post by: mattsoft on January 22, 2019, 11:46:16 am
Quote from: amigo-mexicano on January 22, 2019, 08:48:28 am
What a cool project! Been reading all day long about it. Congrats mattsoft, and thanks for sharing!

Now, this says it's for the ACE, but should work for any model, right? I want to use it on a SUPER... :)


I don't know what a Super's PSU looks like. The board was measured and designed to fit into an ACE/ACE HD "lego" style PSU. If the Super has the same shape PSU and basic power requirements, then it should work. But your mileage may vary. :)
Title: Re: Easy PicoPSU
Post by: leonk on January 23, 2019, 04:06:21 am
As Matt mentioned, it will work in any lego PSU. I installed it into an XVI HD.
Title: Re: Easy PicoPSU
Post by: amigo-mexicano on January 23, 2019, 05:26:10 am
Great, I'm gonna try on a PRO also, and see how it goes...
Title: Re: Easy PicoPSU
Post by: thegirlg33k on January 27, 2019, 08:20:22 am
It works wonderfully! Now to actually get it hooked up to my OSSC and test. :D
Title: Re: Easy PicoPSU
Post by: X-Col on March 10, 2019, 10:10:54 am
Amazing work!

Well done mattsoft!!  ;)
Title: Re: Easy PicoPSU
Post by: hyrulebr on March 26, 2019, 12:47:32 am
Hey Mattsoft!

Just won a X68000 OG (CZ-600C) and for sure it will need a new ps. Do you have anything for a OG? I don´t know if the ps and connectors are different from a Ace for example.

Title: Re: Easy PicoPSU
Post by: leonk on March 26, 2019, 01:31:30 am
I restored an OG X68000 as my first one ..

The power supply here is not the same.  The OG X68000 doesn't have a "tetris" PSU, it has a PSU that's more similar to a 1U micro PC.

Don't use the original PSU.  Replace it!  Also, the other killer of these computers is the on board save battery.  They put it a few mm away from the main crystal!!  If the battery leaked, it would have killed it.  Contact me and I can help you restore that.
Title: Re: Easy PicoPSU
Post by: hyrulebr on March 26, 2019, 02:19:45 am
Hi Leon!

I appreciate your message and I do want your help!  :)

It will take a while to me receive the OG. I used shoppingmalljapan to buy from YAJ and I intend to use all 30 days of free storage I have. This will help me to have the money to pay shipping to Brazil, which is very expensive for a (heavy) X68000 ...

I bought this one:

https://page.auctions.yahoo.co.jp/jp/auction/n335264270

I expected to pay less in an OG but lack of patience overcame me! I was tired of waiting for a better price. :-[

The good news is that it´s turning on, asking for the OS and ejecting discs. That's a good sign but I know that I can´t keep this ps.

I already have a 1MB extension board bought brand new from Beep!. Just want that both drivers are in working conditions.  8)








Title: Re: Easy PicoPSU
Post by: mattsoft on March 26, 2019, 02:36:33 am
Quote from: hyrulebr on March 26, 2019, 12:47:32 am
Hey Mattsoft!

Just won a X68000 OG (CZ-600C) and for sure it will need a new ps. Do you have anything for a OG? I don´t know if the ps and connectors are different from a Ace for example.


the original PicoPSU board (https://github.com/mattsoft/X68K_EZ_Pico_PSU) should work fine for an OG X68000 as it doesn't rely on the "lego" style brick. i don't have any made up at the moment, but you can have several made from China for around $20. or you can just wire the circuit manually without the board.

the newer style board I do have spares for are only for the "lego" PSU and therefore will not fit the OG. :(
Title: Re: Easy PicoPSU
Post by: aje_fr on April 04, 2019, 06:59:50 am
I'm always amazed that people spend so much time trying to replace these blocks while once repaired they are really reliable.
I'm sure you spent as much time replacing the blocks rather than repairing it.
Title: Re: Easy PicoPSU
Post by: vanpeebles on April 04, 2019, 07:13:10 pm
Even repaired, the original PSU can be a weak link. I live in a 240v country, so it's a way better solution than using a dodgy original with a stepdown tagged on the end as well.  :)
Title: Re: Easy PicoPSU
Post by: leonk on April 05, 2019, 02:41:24 pm
Even if it’s repair to like new condition, the original design is more than 30 years old and poor. It will fail again the same way. PSU technology improved. Why take the chance?
Title: Re: Easy PicoPSU
Post by: aje_fr on April 06, 2019, 10:59:13 pm
Quote from: leonk on April 05, 2019, 02:41:24 pm
Even if it’s repair to like new condition, the original design is more than 30 years old and poor. It will fail again the same way. PSU technology improved. Why take the chance?


The design is maybe 30 years old but still really, really reliable, no specific components, only discrete. No compromise on cost vs quality when designed. If I follow you, why still using original motherboard when a fpga could do the same...

Why when you change all leaky components it still works perfectly. The psu is really well designed.

I don't think modern psu could last so much time... From my experience, their lifetime is around 10 years.
Modern psu are too sensitive and not reliable due to the fact that their components are used to their limits to save costs.

And when you repair the original one, you could put high quality components. Something you'll never find in cheap modern psu.
Title: Re: Easy PicoPSU
Post by: leonk on April 07, 2019, 02:39:37 am
Have you tried restoring one of these PSUs and had any level of success with it? I have. replaced almost every component (at high cost from digi-key I might add). still failed. Ended being the wire inside the transformer were melted/fused. Put the picoPSU into the XVI.

Modern switching power supplies can be had of higher quality than your Amazon China special with a lot more safety features and better filtering.

In my OG X68k I have a modern 1U server grade PSU. I replaced the caps with Nichicon just as a precaution even though it was a very expensive PSU already (relative to common desktop ATX power supplies). I know this would last longer than anything I could have done with the stock.
Title: Re: Easy PicoPSU
Post by: Jehuty on April 07, 2019, 06:35:36 pm
When my x68000 PSU gone dead i replaced all leaked caps withnew ones and had no luck. Still a failure in another part.
Finaly i replaced it with a new one and been happy.
Title: Re: Easy PicoPSU
Post by: aje_fr on April 07, 2019, 08:12:13 pm
I got 100% success on all PSU I repaired... And trust me, I have done somes...
Title: Re: Easy PicoPSU
Post by: TD-Linux on April 11, 2019, 07:49:40 am
Quote from: leonk on April 07, 2019, 02:39:37 am
Have you tried restoring one of these PSUs and had any level of success with it? I have. replaced almost every component (at high cost from digi-key I might add). still failed. Ended being the wire inside the transformer were melted/fused. Put the picoPSU into the XVI.


Mine also has a clearly broken transformer. The way the PSU is designed, when the primary side transistor fails short, it will also cook the transformer winding and possibly some resistors in the same route.
Title: Re: Easy PicoPSU
Post by: leonk on April 11, 2019, 01:21:22 pm
Here’s an example of one that leaked so bad, parts were falling off the PCB. Everything was cooked including the transformer and the fuse exploded and caught on fire at some point.

Note all the wonderful capacitor gunk.

(http://u.cubeupload.com/leonk/XCG2CT.jpeg)
Title: Re: Easy PicoPSU
Post by: neko68k on April 12, 2019, 01:24:03 am
geez mine didn't look that bad lol... My Pro had an SH5 in it that already had higher rated caps than I've seen listed anywhere, even in guides advising higher ratings and it was still dead. I recapped it myself and it stayed dead so I threw it in the trash. Aint nobody got time for that.
Title: Re: Easy PicoPSU
Post by: cauterize on June 10, 2019, 07:16:58 pm
Matt very kindly sorted me out with an Easy PicoPSU recently (and with a lot of technical assistance too) - despite my limited knowledge working on such fiddly electronics, it really was a straightforward to install in an Ace HD. I feel much safer knowing I've removed the board and those troublesome capacitors, so here's to plenty more gaming on the X68000!
Title: Re: Easy PicoPSU
Post by: cometclean on September 16, 2019, 03:19:22 pm
Greetings,

I have a an Expert X68000 with what I believe to be a broken psu. Are there any more power supplies available? I am assuming the LEGO type will work with Expert?


Cheers!
Title: Re: Easy PicoPSU
Post by: mattsoft on September 17, 2019, 03:52:56 am
I have a couple of more spare boards if you need one, but I don't know if the Expert uses the same PSU as the ACE or not. Hopefully someone else knows!

Quote from: cometclean on September 16, 2019, 03:19:22 pmGreetings,

I have a an Expert X68000 with what I believe to be a broken psu. Are there any more power supplies available? I am assuming the LEGO type will work with Expert?


Cheers!
Title: Re: Easy PicoPSU
Post by: hoshikawa on September 17, 2019, 01:49:39 pm
all manhattan shape models from ACE to '030 use the same size power supply, the so called tetris block. i'm using a mattsoft board in an EXPERT II.
Title: Re: Easy PicoPSU
Post by: 3rdman01 on September 23, 2019, 03:21:20 am
Quote from: mattsoft on September 17, 2019, 03:52:56 amI have a couple of more spare boards if you need one, but I don't know if the Expert uses the same PSU as the ACE or not. Hopefully someone else knows!


Hello! I've recently purchased my first X68K...I don't completely know what I've gotten myself into yet (LOL) but I am certain that the first thing I need to do when my machine arrives is to change the PSU. With that said, I've stumbled onto this thread which lead me to your github page with the BOM. It seems that the PSU you chose is sold out with an LONG lead time...I am think of getting the higher-rated version (120W) as it has the exact same foot print. I don't believe there are downsides to this but I thought I'd ask your opinion. Also, I've never used Gerber or KiCad and not wholly sure how to use these files when ordering. If you have any more spare PCBs, would you sell me one?

Thank you!
Title: Re: Easy PicoPSU
Post by: mattsoft on September 23, 2019, 04:52:19 am
You should be fine with the higher wattage one. Let me know if you need any help!
Title: Re: Easy PicoPSU
Post by: 3rdman01 on September 23, 2019, 05:36:41 am
Excellent! I'll get to buying the pieces.

How about the PCB itself? Any spares on hand that you could sell me? Thanks again!
Title: Re: Easy PicoPSU
Post by: mattsoft on September 23, 2019, 08:35:56 am
Quote from: 3rdman01 on September 23, 2019, 05:36:41 amExcellent! I'll get to buying the pieces.

How about the PCB itself? Any spares on hand that you could sell me? Thanks again!

I have 3 boards left and can spare 1. After that, I'll need to keep the remaining 2 for projects. If more people want them, I'll order another batch and make them available.
Title: Re: Easy PicoPSU
Post by: ashrion on September 25, 2019, 05:44:31 am
Pico psu posibility problems is very high.
For my  x30  bought one psu original in japan 100% new components. All new, not expensive cost, machine is very
expensive and I have not problem in pay it if works  perfectly . I  use my x30 with 12mb ram inside motherbard principal 8 mb ram, midi, original monitor 21" Sharp x68. x68030 is  mod version 100% cpu chip mmu mod socket, power is 30% more of a normal x30. 2year  ago I bought a ac  and it works perfectly.

The problems originals ac  are that their use was so little. Computers without use makes the ac to die in  10-20-30 years and because of that ac will be destroyed.


My xvi is a secondary computer, mod atx and ac atx out computer, pico psu not is not good  quality ac component, they has bad components and they are not reliables and some pico psu don't work. They are a poor product. . I don't use it in x68 computers.

Title: Re: Easy PicoPSU
Post by: 3rdman01 on October 08, 2019, 07:33:52 am
So I just received my X68k (Expert HD) in the mail and I'll be plugging in the PicoPSU tonight to test it out (thanks again, Matt)...I don't have a video out yet though so is there any way of testing it without video?

On another note, it came with an unadvertised 4mb expansion!
Title: Re: Easy PicoPSU
Post by: 3rdman01 on October 08, 2019, 11:13:32 am
So I quickly ripped out the old PSU and sure enough, a black scorch mark shows evidence that the PSU was shot. I quickly removed it and wired everything up with the PicoPSU and BOOM it started up right away! It booted to a copy of Gradius that the seller left in the drive and couldn't remove.

So happy! Next thing to do is rip open the base and check/replace the battery and then seriously clean it...It smells awful...The previous owner was serious about smoking and seemed to be dedicated to never cleaning it.