PowerBook Power Supply Connector (520/520c/540/540c)

jmacz

Well-known member
I wanted to share information on this PowerBook 5xx Power Supply Connector I have been toying with. Been so busy with other projects lately that I only got a chance to play with this a bit more today. I have not yet worked on the actual power supply yet but I wanted to at least share the connector incase anyone wanted to give it a try.

My goal was recreate the power connector for the PowerBook 520/520c/540/540c power supply since it seems to be a proprietary connector.

Here's my design/model:

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The idea was to 3D print the body/cap and use metal for the shield. I made an initial prototype using filament printing just to make sure the size/structure was correct. It was clear right from the first print that there was no way filament printing was going to provide the precision necessary for the fine holes, etc. So for the real thing, I used a resin printer.

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This is straight out of the printer with the supports cut away. The size was good enough and the only sanding I did was to smoothen where the supports were. But the rest of the measurements were good and did not require any sanding.

Now for the metal shield. The shield makes contact with the interior of the power socket (laptop side) and goes to chassis ground within the laptop. I needed something strong but conductive. I opted for stainless steel. Not the best for conductivity but I'm hoping it's good enough (maybe an expert can chime in here). It was testing fine with my multimeter but I'm not an electrical person.

To create the metal shield, I bought a 10mm (outside diameter) stainless steel tube with a wall thickness of 0.5mm which is very close to the stock connector.

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I then cut a 12mm piece off the end using a dremel. Probably should have used my lathe but a dremel worked fine.

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I then cut a 1mm slit in it to make a "C" ring. The 3D printed body has a slot for this ring to fit in. It's a tight fit and snug, it's not coming out. Here's a picture with the shield inserted and the cap in place.

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For the actual pins, I bought some of the crimp pins that @Fizzbinn found on Amazon that fit the power pins perfectly. I also purchased a 5mm diameter cable with 5 internal strands, one for each of the 4 pins and 1 for the shield ground. Then soldered/crimped the crimp pins onto four of the strands and soldered the black strand to the shield inside the connector body.

The soldering to the metal shield took some additional thought. It's stainless steel and so will NOT solder using standard solder wire or flux. I had to get special flux made for stainless steel as well as some flux with some silver in it. That worked well. Here's a picture of the assembly.

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And with it inserted into my PowerBook 540c.

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And with the cap on.. note I didn't fully close it as I will most likely epoxy the interior to ensure none of the wires pull out.

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Next step is to build the power supply. I will talk about that in my PowerBook 540c restoration thread.

So as promised, I will attach the STL files to this post. As far as the other parts you will need:
And STL files for the connector body and cap attached to this post.
 

Attachments

  • PB5xxPowerConnector.zip
    116.7 KB · Views: 9

jmacz

Well-known member
After months of use, I found a stress fracture in the connector near the metal grounding shield.

Two thoughts... 1.) I used standard 3d printing resin for this part and I should have used the tough/flexible resin instead for some more give. 2.) there is a lot of clearance in the body of the connector holding the metal shield and I can make it thicker for more strength.

Screenshot 2024-01-04 at 7.43.24 PM.png

The above picture is a new revised version with the part pointed at by the red arrow is thicker now. The stress fracture was where that part meets the rest of the body.

I am attaching v2 of the STL files with that part thicker.

Everything else on the connector has been working great since August. I've printed a new one with tough resin and hopefully the change plus the resin change resolves this.
 

Attachments

  • PBConnector-v2.zip
    313.2 KB · Views: 9

wottle

Well-known member
FYI, I printed a batch of these at JLCPCB in their black resin (I only have an FDM printer and I tried to print and it was not up to the task). Their black resin is a nice dark gray color - slightly darker than the 5xx series. They turned out great. I ended up switching from a cutting disk to a grinding disk on my Dremel tool to remove a bit more material when cutting the slot and I've gotten very good results. I have been only connecting the VMAIN and Ground lines because I don't have any working 5xx batteries.

IMG_3005.jpeg

One question I have is, I bought the stuff you recommended for soldering to the stainless steel shield. The question I have is what should I hook that to? Do I mate it to ground? I'm using @PotatoFi's USB-C powerbook adapter with a boost converter to get 16v from a 15v USB-C trigger card. I also made and adapter to a 5.5mm standard barrel plug so I could use other things to power it (I wanted to try running it on 12v as I had read someone say they had done that with no issues, and I was hoping maybe it would slow the tunnel effect on my monochrome 520 screen -it did not). For now I just have the wire loose in the 3d printed case, but I feel like I should connect it somewhere.

Thanks - not an electrical engineer and I just like messing with old computers.
 

jmacz

Well-known member
I'm going to let some other experts chime in.

But from what I found, the original stock adapter had both the ground pins and the shield tied to the grounding prong on the 3 prong plug (US). Checking continuity between the shield and ground pin on the stock connector, I was seeing near 0 resistance so they were connected.

With my replacement power supply, it had a 2 prong plug only, and because of that it was incased entirely in plastic (no touchable metal on the adapter housing). And so for this one I also just connected the shield to the ground pins as well.
 

wottle

Well-known member
OK, I may solder that wire to ground then, unless anyone chimes in with a reason not to. Thanks for modeling this!
 

3lectr1cPPC

Well-known member
One question I have is, I bought the stuff you recommended for soldering to the stainless steel shield. The question I have is what should I hook that to? Do I mate it to ground?
The sheath is wired to ground on the stock supply.
 

mmu_man

Well-known member
Oh dear, one more thing I spend entire nights on just for people to redo again… I know, I should publish stuff someday…
I was waiting for the resin printer around to be set up, I'd have published mine then…
In any case, no need to cut metal, the shield of an RCA plug works just fine.

Copie d'écran_20241202_004156.png
 
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