PB 5xx original AC adapter re-cap & modern replacement

[jmacz]

Shared the instructions, parts, and model here:

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

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...

68kmla.org

 

[alexGS]

I probably should have posted in this thread - sorry - but I have started a new thread with my theory of why two supplies are needed. It seems to me that VBatt must be limited to about 1A, or the battery will attempt to charge with all the current available. Please see my post at https://68kmla.org/bb/index.php?threads/500-series-alternative-power-supply-learnings.45726/

 

[jmacz]

Do these two also need to be replaced or should they be ok?

 

[3lectr1cPPC]

I’m not aware of them being failure prone.

 

[jmacz]

Ok, I desoldered them and they look ok (not like RIFAs). Maybe since they're out already, I'll just replace them.

 

[wottle]

FYI, these 3d printed connectors work fantastic. I used them in combination with another project on TinkerDifferent to house a USB-C trigger board and buck or boost converter. I had some problems with the buck / boost boards overheating, and the standard 15v you can get out of a USB-C trigger board was very close to the 16v the stock charger gives. So far, it seems to work fantastically. No problems running off of 15v. I did not hook up the VBATT connections because I don't have a working battery, but in theory you could probably build one with dual USB-C triggers for the two 15v lines.



I only have an FDM printer, and it was not up to the task of printing the plastic connectors, but I used JLCPCB resin printing to produce them and they turned out fantastically. Highly recommend using them if you need something printed and want it to look high quality. Once I got the metal grinding wheel for cutting the stainless steel tubing, I was able to get pretty good results. Soldering the wire to the little bit of exposed stainless for the shell was difficult, but I managed.

 

[jmacz]

Congrats, glad the model worked well for you

 

[Hopfenholz]

My 540c power adapter just died :-(

So I need to build one of these. Question: does this solution - using a 16v adapter from a PC laptop with the orange and red (VMAIN and VBATT) wired to positive - allow the battery to charge when the laptop is sleeping or off, as the OEM one would do?

 

[3lectr1cPPC]

You cannot wire the VBATT wire in with VMAIN because VBATT has to be a 1A current regulated supply. If you have one 16V laptop brick, say at 4A, leaving it plugged in with the laptop powered off when it's wired this way will send 4A straight into the battery - not good.

 

[jmacz]

You really have two choices.

1.) Try to fix your stock power adapter - usually it's bad caps. I've done one. Opening them up without killing the plastic enclosure is really a pain. And once inside, there's some annoying things you have to deal with like desoldering/removing a metal plate. But it's definitely doable.

2.) Build your own power adapter - as @3lectr1cPPC mentioned, you actually need to build it using two power supplies (similar to the stock one). I did this by combining a 16V 4A power supply for vmain and a 15V 1A power supply for vbatt (16V 1A is preferred as that's what the stock adapter had but I could not find a 16V 1A power supply at the time and 15V works fine). And then I 3D printed an enclosure to house them.

Lots of discussions on this in @3lectr1cPPC's thread here: https://68kmla.org/bb/index.php?thr...ery-rebuild-failure-oops-all-dead-emms.46341/

 

[Hopfenholz]

Thanks VMUCH as it were

 

[croissantking]

Thanks VMUCH as it were

I love this

 

[jmacz]

Wow, annoying... I revisited my PB 540c and found that the batteries had drained. Went to charge them and my batteries would not charge. EMMpathy was showing no activity trying to charge them although both are detected, the PB can talk to the EMM board, and showed the charge state is really low (6V on one, 8V on the other).

With these EMMboards sitting inside the battery, I'm guessing they will constantly slowly drain the batteries even if they are left out of the laptop. This seals me decision on whether to build 2 more, there's no point. I don't want to babysit batteries I will just stick with the two I have.

That said, back to the issue at hand of not charging. Tried a bunch of things and no go. I then took a look at the power adapter. no voltage on VBATT. Argh. This is the recapped stock charger... it wasn't working. I had fixed it via a recap. Was working for a while. Now VBATT isn't working on it.

I plugged in my custom built charger and that's working great and both batteries are charging up now.

But this stock adapter, need to open it back up again and see what's wrong. Unfortunately sealed shut the plastic casing and need to break it open again

 

[alexGS]

With these EMMboards sitting inside the battery, I'm guessing they will constantly slowly drain the batteries even if they are left out of the laptop. This seals me decision on whether to build 2 more, there's no point. I don't want to babysit batteries I will just stick with the two I have.

It’s a bit depressing isn’t it… I’m almost at the same point myself, can’t cope with the ‘babysitting’. However, I rebuilt a pack a few weeks ago using new Eneloop Pro AA cells (I spot-welded tabs on) and replaced the memory chip. That battery seems to work well: runtime still only about an hour, but - as expected for Eneloops - self-discharge is less. The Eneloops weren’t as expensive as special cells from China, mainly because AA is standard of course. I made them fit by making a hole in the casing opposite the terminal plate, and trimming away all other ridges that restricted cell length.

 

[croissantking]

My third party battery has a little switch, maybe to overcome the battery draining issue?