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

[3lectr1cPPC]

Yes, minor ones. Although they have seemed to get better as I’ve owned it. Of course, I haven’t been able to do a long running test for about 6 months as this charger was dead, and the other one cuts out after running for around 10-20 minutes. I’m about to be using this one a bunch though tonight so I’ll be seeing how bad it is right now as I go.

 

[3lectr1cPPC]

Rats!!! It just died. Laptop shut off and it made a quick ticking noise when I listened to it up close. That sucks. Any ideas why that could be?

Edit: this is strange. I unplugged it, plugged it back in. Still no boot and making the rapid ticking noise. I decided to see what voltage it was outputting in that state so I unplugged the PowerBook, measured and it’s still 16.5? I listen. No more ticking. And now the PowerBook boots. What the heck? Man power supplies can be weird.

Edit: ok it crashed again. Voltage on VMAIN is 3.8 volts when it’s in this state. What’s up do you think? VBATT remains at 16.5

 

[MacUp72]

View attachment 58426

I found it enerving seeing these old solder jobs/ blobs ..on many places I wasnt sure if parts/pads were connected or not..
right there on your photo, the end of the board-through leg and the pad of c '564'..on mine there was a big solder blob and I had to desolder both parts to see if theres actually a connection beneath it..and well, of course they have common trace..
we dont want to short anything, right?

 

[3lectr1cPPC]

I’ve seen that sort of bodging in all sorts of power circuits. Seems common. I’m just wondering why mine quits working like this, it’s so frustrating!

 

[3lectr1cPPC]

Here’s a recording of the sound it’s making:

View attachment trim.2D0C6A26-C81C-42CA-B5E2-7435E8250748.MOV

 

[croissantking]

It might be really hard to diagnose if it’s a faulty component, though the intermittent behaviour could be a cold solder joint. Check all joints carefully.

Otherwise just do what I did with one of my PSUs whose VMAIN is always at 1.5V - swap the red and orange VMAIN and VBATT cables over, and run it like that. As long as you don’t turn the screen brightness all the way up, it’ll work just fine.

 

[3lectr1cPPC]

I’ll reflow everything for now and see what that does. If it doesn’t solve it, then yeah I’ll swap the wires, that’s a good tip! But that still would kinda stink. I want one of these fully functional because I’m going to be rebuilding my batteries eventually.

 

[MacUp72]

-check all your solder joints
-you already double checked polarity of your new C's?
-check the little component board you swapped C 802 on, it is soldered into the mainboard through 3 pins.
(On mine one of those pins fell off, had to resolder it)
-check continuity of C's and traces where you soldered

ticking noise can have two causes AFAIK
1. the current transformer doesnt deliver enough power and on boot voltage goes down, adapter shuts down and powers up again.
2. the adapter works but one component causes too much current flow, adapter shuts down and up again.

 

[croissantking]

I’ll reflow everything for now and see what that does. If it doesn’t solve it, then yeah I’ll swap the wires, that’s a good tip! But that still would kinda stink. I want one of these fully functional because I’m going to be rebuilding my batteries eventually.

I know - I felt the same at the time but I’m not knowledgeable enough about PSUs to have been able to troubleshoot mine beyond the basics; I suspect there’s a bad component in there. I was hoping the recap would fix it but it didn’t. Then, I scored another 500 series PowerBook on eBay with a good power supply and all is well.

I’ll try to rebuild my PB165 battery first as they say the 500 series is difficult to do. But I do have 2 intelligent batteries so I’ll have a lot of runtime potentially.

 

[3lectr1cPPC]

-check all your solder joints
-you already double checked polarity of your new C's?
-check the little component board you swapped C 802 on, it is soldered into the mainboard through 3 pins.
(On mine one of those pins fell off, had to resolder it)
-check continuity of C's and traces where you soldered

ticking noise can have two causes AFAIK
1. the current transformer doesnt deliver enough power and on boot voltage goes down, adapter shuts down and powers up again.
2. the adapter works but one component causes too much current flow, adapter shuts down and up again.

1. To do today.
2. I suppose I can double check, but I was very careful to get it right during installation and I doubt it would have worked at all if I goofed one up.
3. Vertical board should be soldered properly. I’ll check it’s solder joints like the others

Thanks for your words on the fast ticking. Something sure is up. Worst comes to worst I’ll swap VMAIN and VBATT, then try my luck with my other supply. That one works right now but it cracks out completely after a bit. No voltage out when it crashes.

 

[3lectr1cPPC]

Reflowed everything except for the little cap on the vertical board and no change. It ran for probably about 10 minutes, then I got a low battery voltage warning? Even though I don’t have any batteries installed? Then it shut off, VMAIN 3.8 volts. Hmm. Next step when it discharges fully from mains will be to swap the wires I guess…

 

[3lectr1cPPC]

Here’s a picture of the bottom of my board

 

[3lectr1cPPC]

Attempt 2 will be done later tonight. I bit the bullet and got my second supply cracked open with a vice. Looks like they used different cap vendors in this one.
Supply #2 has not noticeably leaked any yet, but will shut off after running for some time. Complete shutoff, no power to either rail when it does this. Hope that a recap fixes this

 

[MacUp72]

Here’s a picture of the bottom of my board
View attachment 58450

what about cleaning up/redo the old one?
I guess there are some improvable solder joints there, cold solder joints, blobs..maybe solder temp is too low?

 

[croissantking]

what about cleaning up/redo the old one?
I guess there are some improvable solder joints there, cold solder joints, blobs..maybe solder temp is too low?

View attachment 59279

Oh yes, definitely some dry joints there.

 

[3lectr1cPPC]

Hmm, a few of the ones you’ve highlighted are ones I didn’t even touch. I suppose it’s possible some of them have cracked. I’ll reflow some stuff today and then see what it does.

 

[3lectr1cPPC]

I reflowed just about every large joint that’s accessible on it and it still died within 5 minutes of running. The strangest part about it all is that the PowerBook gives a low battery warning (shutting off in 10 seconds) right before it dies, then a few seconds later, it shuts off. This is weird because that means there must not be some sudden drop off to 3 volts because it’s not immediately dying. Also worth noting that it did the same thing before the recap! I assumed before that the batteries which still did have some weak voltage in them ran the system after it died, but nope. No batteries installed this time.

 

[croissantking]

There is a thermal diode in there, on long leads and tucked in quite near the big resistors, perhaps this is faulty – or something is overheating?
Did you replace the small capacitor on the daughterboard?

These PSUs are quite unreliable, I have to say.
Maybe you could save yourself the trouble and get a 16v PC laptop PSU and mount its innards in the PowerBook PSU? The only caveat being that you won't be able to charge batteries.

 

[3lectr1cPPC]

I did replace the vertical board capacitor, yes. Yeah these PSUs really do suck. Hopefully my second one will cooperate better.

 

[MacUp72]

I'm curious if your second power brick behaves the same..