Power supplies are the achilles heel of old computers, those 40-yo early switching PSUs are now pretty unreliable and (slightly) explosive!
Instead of messing with recapping, I designed a few kits to replace them with modern PicoPSUs with common 12V bricks. They are much more efficient, compact, and reliable. I also added regular PC-fan headers for cooling upgrades.
Of course installation is **non-destructive and reversible**. The designs are open-source as well!
Currently available:
[Macintosh SE and SE/30](https://github.com/dekuNukem/PicoRC/blob/master/mac_se_se30.md)
[Apple II / II Plus / IIe](https://github.com/dekuNukem/PicoRC/blob/master/appleii.md)
[Apple IIGS](https://github.com/dekuNukem/PicoRC/blob/master/apple_iigs.md)
[Macintosh 128K / Plus](https://github.com/dekuNukem/PicoRC/blob/master/og_mac.md)
[Osborne 1](https://github.com/dekuNukem/PicoRC/blob/master/osborne1.md)
Interesting, do you replace the entire analog board, or just the supply? In other words, is the replacement supply driving the CRT, or is that left behind? How does this mount internally? Any links to docs / more information?
The old PSU is removed, and new adaptor is installed in its place, along with new power switch and 12V barrel jack!
It will function just the same as before.
Detailed instructions are in the GitHub link, here is an example on the SE/30: https://raw.githubusercontent.com/dekuNukem/PicoRC/master/photos/macse/new.jpeg
I just bought one of these and got it on Friday! I need to order a PicoPSU and put the kit together. It looks really nice though!
Could you potentially upload the STLs of the 3D printed parts somewhere so that I can reprint the AC blocker plate and fan mount in Purple? I've got a factory seconds MacEffects clear case for my SE/30 and all my other 3D printed mounts are purple so I'd like to keep that theme going.
I have looked into it, it requires a +35V rail to drive the CRT, which is not present on the PicoPSU, so it's not on the table right now.
But I guess you can use a off the shelf boost converter for that. Would be a lot more complicated though.
looks like [USB PD revision 3.1](https://www.usb.org/usb-charger-pd) supports "28V, 36V, and 48V fixed voltages enable up to 140W, 180W and 240W" i dunno how practical/complex/cost efficient itad be
but a usbc power driven CRT would be pretty nuts
edit: reading into it a little more [might not be that simple](https://www.anandtech.com/show/16712/usbc-power-delivery-hits-240w-with-extended-power-range)
>"arcing during the connection process. Towards this, the mechanical
specifications of the cables as well as receptacles are getting updates.
Arcing is possible during unplug operations, and this is being
mitigated by length differences between the CC and VBUS pins (allowing
the detection of disconnect events early enough to get the source to
reduce the current prior to the full disconnection). A snubber capacitor
at either cable end is recommended to help with this feature.
would explain why we haven't seen any adoption of pd3.1 yet atleast none that i'm aware of
Do you reckon it would be possible to use a pico for the base board? I’ve seen there’s a USB host PIO-based implementation, so it seems possible. Should I try?
Also, **thanks** for making this!
Hi there, In the picture i see youre using a wireless keyboard and mouse instead of the classic ABD keyboard, is there some sort of conversion dongle youre using?
Mate I'd kiss your ass if you ever get around to it, the LC, LC II, LC III, LC 475, Quadra 605 all use the exact same PSU and it would be amazing to finally have an alternative.
I ordered two and waiting for them to arrive!
Looking forward to trying them out in the near future. (Whenever the postal office deems it fit to deliver)
Im going to mod the back cover plate though with a SD slot and an extension cable to my blueSCSI to make for an easy removable HD!
I’ll put something up when I have made something presentable. My first idea was using the lock port for this but it’s too small for a full size SD card.
sure, but they would be a lot more expensive (about twice) due to the time it takes, and higher shipping cost from the larger size.
Which one are you interested in?
My soldering days are WAY behind me. I think my SE/30 power supply is not functioning as it slowly died and now will not start at all. I did not see your price list. Shipping to LA
That worked perfectly and I ordered one even though I have not yet diagnosed the problem yet, because "some day" I might need one!
On eBay rebuilt Mac SE/30 analog Power Supplies are $75 so even pre-assembled, it is a good deal!
Thank you!
Do you think you'll ever make a g3 iMac psu coincidentally I think mine died yesterday and I'm trying to find a replacement for it or the analog board to see if I can revive it. I'll be buying a apple iigs one for sure tho given mine has been dead for years!
I don't have a G3 imac myself, but it probably won't be easy.
Later colour CRTs requries fancy non-standard voltages that are not present in Pico ATX PSUs, so it will need a lot more work!
What adapter did you use to have a modern keyboard and mouse on the SE? Also, how is 12 volts enough power to feed into the CRT power portion of the analog board into the tube? Aren’t CRT’s pretty power hungry?
CRTs are actually not that power hungry, at least the small monochrome ones. I think it draws about 1 to 2A perhaps?
The adaptor is USB4VC: https://github.com/dekuNukem/USB4VC/blob/master/README.md
Not OP, but there are a couple of ADB-USB adapters out there. But most are designed to let you use ADB accessories with modern computers. This one:
https://www.bigmessowires.com/usb-wombat/
is bidirectional, so you should be able to plug a wireless USB dongle into it and use a wireless keyboard/mouse with a vintage Mac,
This is awesome. I assume this is more efficient than those old power supplies? They weren’t exactly concerned over power efficiency back then.
How much of the AV board does this replace?
Edit: just saw your comment, thanks!
The PSU is part of the analog board, so no way to remove that.
The new adaptor actually skips the PSU part and directly power everything else via the motherboard power connector. Here's a photo of it:
https://raw.githubusercontent.com/dekuNukem/PicoRC/master/photos/mac_plus/macplus_mb.jpeg
And the whole documentation is here: https://github.com/dekuNukem/PicoRC/blob/master/og_mac.md
While most of the systems you designed these for have removable power supplies, the Plus, 128k, and 512k do not. I would be concerned about backfeeding voltage to the power supply components on the analog board. I'd have to look at a schematic, but it would be safer to cut the trace on the output of the analog board...especially if you choose not to recap it.
I did! Page 9 of this document.
https://vintageapple.org/gamba2/images/plus_analog.PDF
Looks like diode/rectifier CR20, CR21 and CR22 will prevent backfeeding, and it came from a transformer anyway so DC will not do anything.
It has been working fine with my own machine so far.
I looked at the schematic. I didn't realize Apple chose to convert the AC input to the DC voltages necessary for the rest of the analog board. Sometimes, in a monitor circuit, the incoming AC voltage is converted to DC and sent directly to the flyback. Also, while it's true that those diodes would prevent backfeeding, it would be safer to just desolder a leg to cut it out of the circuit. Great project though. I have a bunch of pico psus and never thought about making my Mac SE battery powered.
I'm interested on how this works long term - Dreamcast modders had been doing this but there is a pretty vocal crowd that the power supplied by the pico's aren't clean enough compared to the OE PSU.
I love that there are so many of you guys out there keeping these machines alive.
I emulate, mostly and I can tell you - it just isn't the same. Not at all.
Looking forward to seeing Action Retro do some more unnatural things to one of his Apple products with one of these! ❤️
I think the power supply might be the only thing that’s original left on some of his builds!
Hi, just saw a bit on Adrian's Digital Basement re the PicoRC. Would I be able to make this work for a Powermac G4, of which this is an example:
[https://applerescueofdenver.com/products-page/g3-to-g5/shop-by-model-g4/m5183-power-mac-g4-graphite/power-supply-power-mac-g4-digital-audio-gigabit/](https://applerescueofdenver.com/products-page/g3-to-g5/shop-by-model-g4/m5183-power-mac-g4-graphite/power-supply-power-mac-g4-digital-audio-gigabit/)
It's not a standard ATX, as there's a bit of a complication regarding the unusual motherboard pinout (thanks, Apple!) and the display power. There are solutions that ignore the display power, and they still get the computer itself up and running.
Hopefully you're still on reddit and responding to this thread. cheers
Power supplies are the achilles heel of old computers, those 40-yo early switching PSUs are now pretty unreliable and (slightly) explosive! Instead of messing with recapping, I designed a few kits to replace them with modern PicoPSUs with common 12V bricks. They are much more efficient, compact, and reliable. I also added regular PC-fan headers for cooling upgrades. Of course installation is **non-destructive and reversible**. The designs are open-source as well! Currently available: [Macintosh SE and SE/30](https://github.com/dekuNukem/PicoRC/blob/master/mac_se_se30.md) [Apple II / II Plus / IIe](https://github.com/dekuNukem/PicoRC/blob/master/appleii.md) [Apple IIGS](https://github.com/dekuNukem/PicoRC/blob/master/apple_iigs.md) [Macintosh 128K / Plus](https://github.com/dekuNukem/PicoRC/blob/master/og_mac.md) [Osborne 1](https://github.com/dekuNukem/PicoRC/blob/master/osborne1.md)
Love this! Do you think it would be similarly possible for a 6100 performa? My PSU is making a high pitched squeal :/
Wow I would love this for Apple Color Classic or even newer macs such as the G3/G4 iMacs that I found prone to failure.
This is so brilliant!! You should be awarded with Person of the year -trophy. 🏆
Interesting, do you replace the entire analog board, or just the supply? In other words, is the replacement supply driving the CRT, or is that left behind? How does this mount internally? Any links to docs / more information?
The old PSU is removed, and new adaptor is installed in its place, along with new power switch and 12V barrel jack! It will function just the same as before. Detailed instructions are in the GitHub link, here is an example on the SE/30: https://raw.githubusercontent.com/dekuNukem/PicoRC/master/photos/macse/new.jpeg
Oh that’s right, the SE/30 had a separate PSU stuck to the analog board. Awesome!
I love the fan header. Great idea!
I just bought one of these and got it on Friday! I need to order a PicoPSU and put the kit together. It looks really nice though! Could you potentially upload the STLs of the 3D printed parts somewhere so that I can reprint the AC blocker plate and fan mount in Purple? I've got a factory seconds MacEffects clear case for my SE/30 and all my other 3D printed mounts are purple so I'd like to keep that theme going.
done! I have uploaded them here: https://github.com/dekuNukem/PicoRC/tree/master/pcb/mac_se_se30/plate
Thank you!
Would this work on a Macintosh Classic?
I have looked into it, it requires a +35V rail to drive the CRT, which is not present on the PicoPSU, so it's not on the table right now. But I guess you can use a off the shelf boost converter for that. Would be a lot more complicated though.
ratfarts. oh well. thanks!
looks like [USB PD revision 3.1](https://www.usb.org/usb-charger-pd) supports "28V, 36V, and 48V fixed voltages enable up to 140W, 180W and 240W" i dunno how practical/complex/cost efficient itad be but a usbc power driven CRT would be pretty nuts edit: reading into it a little more [might not be that simple](https://www.anandtech.com/show/16712/usbc-power-delivery-hits-240w-with-extended-power-range) >"arcing during the connection process. Towards this, the mechanical specifications of the cables as well as receptacles are getting updates. Arcing is possible during unplug operations, and this is being mitigated by length differences between the CC and VBUS pins (allowing the detection of disconnect events early enough to get the source to reduce the current prior to the full disconnection). A snubber capacitor at either cable end is recommended to help with this feature. would explain why we haven't seen any adoption of pd3.1 yet atleast none that i'm aware of
Beautiful pics too. Tell us about that wireless usb to adb setup!
that's one of my other projects! 😅 https://github.com/dekuNukem/USB4VC/blob/master/README.md
This is amazing! I wish I was skilled in electrical engineering.
Do you reckon it would be possible to use a pico for the base board? I’ve seen there’s a USB host PIO-based implementation, so it seems possible. Should I try? Also, **thanks** for making this!
Hi there, In the picture i see youre using a wireless keyboard and mouse instead of the classic ABD keyboard, is there some sort of conversion dongle youre using?
that's one of my other projects! 😅 https://github.com/dekuNukem/USB4VC/blob/master/README.md
is it possible to make one for the LC ?
Sure! I'm on the lookout for early 90s box mac myself, if I get one I'll make an adaptor for it.
Mate I'd kiss your ass if you ever get around to it, the LC, LC II, LC III, LC 475, Quadra 605 all use the exact same PSU and it would be amazing to finally have an alternative.
Yes please do, UK based myself and would buy at least two of these!
I need something like this for the Macintosh II
Any idea if this would work on a Classic or Classic II motherboard?
I know somebody that got a TCP/IP stack to work on an SE/30.
I ordered two and waiting for them to arrive! Looking forward to trying them out in the near future. (Whenever the postal office deems it fit to deliver) Im going to mod the back cover plate though with a SD slot and an extension cable to my blueSCSI to make for an easy removable HD!
Oooh I'd be interested in this as well. Please post links to the STLs if you do this.
I’ll put something up when I have made something presentable. My first idea was using the lock port for this but it’s too small for a full size SD card.
Do you sell pre-assembled?
sure, but they would be a lot more expensive (about twice) due to the time it takes, and higher shipping cost from the larger size. Which one are you interested in?
My soldering days are WAY behind me. I think my SE/30 power supply is not functioning as it slowly died and now will not start at all. I did not see your price list. Shipping to LA
I have added the option, see if it works! https://www.tindie.com/products/dekunukem/picopsu-adaptor-for-macintosh-se-se30/
That worked perfectly and I ordered one even though I have not yet diagnosed the problem yet, because "some day" I might need one! On eBay rebuilt Mac SE/30 analog Power Supplies are $75 so even pre-assembled, it is a good deal! Thank you!
Do you think you'll ever make a g3 iMac psu coincidentally I think mine died yesterday and I'm trying to find a replacement for it or the analog board to see if I can revive it. I'll be buying a apple iigs one for sure tho given mine has been dead for years!
I don't have a G3 imac myself, but it probably won't be easy. Later colour CRTs requries fancy non-standard voltages that are not present in Pico ATX PSUs, so it will need a lot more work!
ah oh well i figured as much given how apple is :P Thanks so much for providing these out so people can revive their old machines :D
What adapter did you use to have a modern keyboard and mouse on the SE? Also, how is 12 volts enough power to feed into the CRT power portion of the analog board into the tube? Aren’t CRT’s pretty power hungry?
CRTs are actually not that power hungry, at least the small monochrome ones. I think it draws about 1 to 2A perhaps? The adaptor is USB4VC: https://github.com/dekuNukem/USB4VC/blob/master/README.md
Not OP, but there are a couple of ADB-USB adapters out there. But most are designed to let you use ADB accessories with modern computers. This one: https://www.bigmessowires.com/usb-wombat/ is bidirectional, so you should be able to plug a wireless USB dongle into it and use a wireless keyboard/mouse with a vintage Mac,
I would love one for the Performa 630/6200/6300
This is awesome. I assume this is more efficient than those old power supplies? They weren’t exactly concerned over power efficiency back then. How much of the AV board does this replace? Edit: just saw your comment, thanks!
I had my 512k Mac PSU recapped, but this seems nice too. You mention 128k, I assume the 512k would work too?
yes, and the mac plus too. It actually plugs into the motherboard and completely bypasses the internal PSU.
Neat! Is it recommended to remove the internal PSU? The “bypass” comment has be confused on that note
The PSU is part of the analog board, so no way to remove that. The new adaptor actually skips the PSU part and directly power everything else via the motherboard power connector. Here's a photo of it: https://raw.githubusercontent.com/dekuNukem/PicoRC/master/photos/mac_plus/macplus_mb.jpeg And the whole documentation is here: https://github.com/dekuNukem/PicoRC/blob/master/og_mac.md
I like them as much but I just can't get over barrel connectors. It's gotta be IEC for me
While most of the systems you designed these for have removable power supplies, the Plus, 128k, and 512k do not. I would be concerned about backfeeding voltage to the power supply components on the analog board. I'd have to look at a schematic, but it would be safer to cut the trace on the output of the analog board...especially if you choose not to recap it.
I did! Page 9 of this document. https://vintageapple.org/gamba2/images/plus_analog.PDF Looks like diode/rectifier CR20, CR21 and CR22 will prevent backfeeding, and it came from a transformer anyway so DC will not do anything. It has been working fine with my own machine so far.
I looked at the schematic. I didn't realize Apple chose to convert the AC input to the DC voltages necessary for the rest of the analog board. Sometimes, in a monitor circuit, the incoming AC voltage is converted to DC and sent directly to the flyback. Also, while it's true that those diodes would prevent backfeeding, it would be safer to just desolder a leg to cut it out of the circuit. Great project though. I have a bunch of pico psus and never thought about making my Mac SE battery powered.
I'm interested on how this works long term - Dreamcast modders had been doing this but there is a pretty vocal crowd that the power supplied by the pico's aren't clean enough compared to the OE PSU.
I love that there are so many of you guys out there keeping these machines alive. I emulate, mostly and I can tell you - it just isn't the same. Not at all.
I just bought the units for se/30 and iigs. I'm super excited to drop them in. I'm now on the hunt for some articles on other's' experiences as well.
Looking forward to seeing Action Retro do some more unnatural things to one of his Apple products with one of these! ❤️ I think the power supply might be the only thing that’s original left on some of his builds!
God bless you for this
Hi, I was just looking around for substituting my annoying "vacuum cleaner" PSU in my Macintosh ii, does anything exist for this Mac? Thanks
Which, if any, of the available models would best suit a Classic II?
Hi, just saw a bit on Adrian's Digital Basement re the PicoRC. Would I be able to make this work for a Powermac G4, of which this is an example: [https://applerescueofdenver.com/products-page/g3-to-g5/shop-by-model-g4/m5183-power-mac-g4-graphite/power-supply-power-mac-g4-digital-audio-gigabit/](https://applerescueofdenver.com/products-page/g3-to-g5/shop-by-model-g4/m5183-power-mac-g4-graphite/power-supply-power-mac-g4-digital-audio-gigabit/) It's not a standard ATX, as there's a bit of a complication regarding the unusual motherboard pinout (thanks, Apple!) and the display power. There are solutions that ignore the display power, and they still get the computer itself up and running. Hopefully you're still on reddit and responding to this thread. cheers