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

[jmacz]

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:





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.



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.



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



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.



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.



And with it inserted into my PowerBook 540c.





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.



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:

• Crimp Pins (thanks @Fizzbinn): https://www.amazon.com/dp/B00EDG0KI4
• Stainless Steel Tube: https://www.amazon.com/dp/B099QLMZLX
• Cable: https://www.amazon.com/dp/B0B942SY29
• Stainless Steel Flux and Solder: https://www.amazon.com/dp/B0015H6JYS

And STL files for the connector body and cap attached to this post.

 

[jmacz]

Oh, and one more thing... I used Rustoleum Satin Charcoal Gray for the paint It was pretty close to the color.

Spray Paint: https://www.amazon.com/dp/B07W9KPB78

 

[Fizzbinn]

Amazing work. …really just awesome!

 

[Gunzel]

That’s awesome @jmacz really great to see this recreated and working!

 

[jmacz]

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.



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.

 

[wottle]

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.



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]

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]

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

 

[3lectr1cPPC]

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]

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.

 

[jmacz]

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.

thanks for the tip on the shield from an RCA plug, that makes it much easier.

 

[wottle]

thanks for the tip on the shield from an RCA plug, that makes it much easier.

I went through so many cutoff blades on my Dremel!!! However, these connectors aregreat, and I highly recommend JLC3DP for printing in resin for a very professional finish.

 

[croissantking]

I went through so many cutoff blades on my Dremel!!! However, these connectors aregreat, and I highly recommend JLC3DP for printing in resin for a very professional finish.

View attachment 83930View attachment 83931

Nice - which resin option did you go for to get that grey finish?

 

[wottle]

Nice - which resin option did you go for to get that grey finish?

Unfortunately, it was the "Black resin" option that it looks like they are phasing out - I don't believe you can use it for new orders. It was a really nice option for Powerbooks - still too dark, but not a black, more of a dark gray.

It also had nice, smooth finish that almost had a soft touch kind of feel to it. I'm going to be trying the new resin, JLC black, and Imagine Black. I ordered a JLC resin and it had sanding lines and did not look great. I believe Imaging Black has an oil finish that I'm hoping will smooth it out like the Black Resin was. However, the JLC Black was a very close match to my Macintosh TV.

 

[mmu_man]

OK, I was reluctant because I wasn't sure it'd like 15V but it seems people are doing it regardless, so might as well make it without extra wires…





Still a few tweaks to make assembly easier but it works.

 

[mmu_man]

I really want to confirm from schematics/PCB, but at least testing with AAUI+VGA output, HDD, full brightness, starting Netscape and using the floppy works OK.

 

[jmacz]

OK, I was reluctant because I wasn't sure it'd like 15V but it seems people are doing it regardless, so might as well make it without extra wires…

Just to clarify, are you using a single power source for both the vmain pin and the vbatt pin in the connector?

I am using two power supplies (similar to what Apple did with their power adapter). One is a 16V 4A/2A for the vmain pin and the second is a 15V 1A for the vbatt pin. I have both power supplies inside a single enclosure again similar to what Apple did.

I don't believe anyone has tried running 15V for the vmain. We're all using 16V for vmain to power the laptop. Some of us are using 15V for the vbatt pin for charging the battery.

Keep in mind that if you intend to use your setup for charging rebuilt batteries, you need to be aware that the batteries do NOT have any form of current limiter. This is why Apple had a second power source limited to 1A for the vbatt pin and why I'm using a 15V 1A for the vbatt pin. If you don't restrict to 1A, you're going to overheat the battery.

 

[mmu_man]

Just to clarify, are you using a single power source for both the vmain pin and the vbatt pin in the connector?

I am using two power supplies (similar to what Apple did with their power adapter). One is a 16V 4A/2A for the vmain pin and the second is a 15V 1A for the vbatt pin. I have both power supplies inside a single enclosure again similar to what Apple did.

I don't believe anyone has tried running 15V for the vmain. We're all using 16V for vmain to power the laptop. Some of us are using 15V for the vbatt pin for charging the battery.

Keep in mind that if you intend to use your setup for charging rebuilt batteries, you need to be aware that the batteries do NOT have any form of current limiter. This is why Apple had a second power source limited to 1A for the vbatt pin and why I'm using a 15V 1A for the vbatt pin. If you don't restrict to 1A, you're going to overheat the battery.

No, it's only Vmain. While I did rebuild my battery, I think most of them around are dead anyway, so for those who don't care that'd be enough.

I know there are 2 separate PSUs, now I don't know exactly why. Are you sure it's because the laptop doesn't cap the current or just because it was cheaper than a single 3A PSU? A real charger circuit will never start at 16V for a 9.6V battery. Also these batteries have a quite complex BMS inside with a funky shunt resistor to measure current, which is supposed to handle this, unlike the 1xx series. I'd like to get an official source for that. Ideally we'd have schematics to assert that. I still intend to reverse the PCB but it takes time. Another option would be to add a current limiter circuit inside the plug, but I really want to make sure it's necessary first.

Btw, don't even think about using one of these "current limiting" PCBs from aliexpress, the shunt is on the ground side on these, so if you short the input and output ground, as is the case on the PB 5xx, well, you short the shunt as well, so it will never limit anything.

 

[mmu_man]

Just checked: the charge circuit pulls 1A from Vbatt for 10s when initially plugged in, so it goes down to 12V. So yeah, quite braindead. Also, it only starts charging if Vmain is also present, probably to avoid pulling from Vbatt for the CPU. Now oddly enough, if you remove Vmain and the battery, it works from Vbatt. Very weird design.

 

[jmacz]

I can't validate the voltage. But I believe one of the guys saw the current pull in practice. I also saw my batteries pulling 2A with a 2A charger and they seem to hit a temperature cut off and stop charging (didn't get a full charge) whereas with 1A it charges completely.