520c: Help Needed

[macosten]

yeap I figured your AC adapter failed. thats why your machine locked up and goofed up. 

common problem. The issue at this point is trying to recap it. the case will shatter like glass when you attempt to snap it apart. Trust me. 

15+ years ago when these adapters first started leaking caps, you could easily pry the case apart without breaking it too much. 

now, its like glass. 

I briefly tried, and it splintered a bit... 

Any suggestions for replacements? Which caps should be recapped, or (if I steal the plug off the end) are there any other known supplies I can just splice the plug onto and get it to work?

Edit: the computer should still work, right? Is it likely the PSU goof-up took anything else with it?

 

[tjjq44]

Alright, I've got the multimeter!

...I stuck wires into pins 1, 2, and 3 (not all at the same time - don't wanna cross anything). From 1 to 3, the current is 16.5 V... but from 2 to 3, it's only around 2.1 V.

Something tells me that might be part of (if not most of) my problem, huh?

Well, anything I can do about this one?  Caps to pick up, instructions on how to take the PSU apart?

When you'll get it opened, try to invert wires "1" and "2" just to see if it boots and exclude another problem on the powerbook itself!

 

[macosten]

When you'll get it opened, try to invert wires "1" and "2" just to see if it boots and exclude another problem on the powerbook itself!

There's an interesting suggestion. :O

So I guess that might be a temporary fix (it'll make the battery slow to charge, if it charges at all, though, I think?).

Would there be a way to take the plug from the PSU and hook it up to a more generic power supply and get it to work? Maybe there's a 15 or 16V PSU somewhere that would work for this?

Or would it just be better to smash the PSU brick casing open (since it's super-brittle anyway and I've already chipped it I'm not really concerned about its condition anymore; I could just try 3D printing something at the Forge) and recapping the PSU?

If I were to recap the PSU, what caps would I need? I assume it's a capacitor issue and not just a fuse issue since if it were a fuse issue I imagine the entire PSU would appear dead, not just VMain.

 

[tjjq44]

Si old batteries will never charge, even with a known good PSU... I just suggest you use vbatt (which seems to be ok) to power the computer and see if it boots. If it boots then go recap your PSU, if not maybe it'll be cheaper to buy another powerbook instead (540c are great, avoid 540 (non c) cause their displays tend to dark in the corners and there is no real fix for this)

 

[macosten]

Si old batteries will never charge, even with a known good PSU... I just suggest you use vbatt (which seems to be ok) to power the computer and see if it boots. If it boots then go recap your PSU, if not maybe it'll be cheaper to buy another powerbook instead (540c are great, avoid 540 (non c) cause their displays tend to dark in the corners and there is no real fix for this)

I've got a battery I've recelled, and it works, though the computer won't boot off it (especially now that I removed the PRAM battery ).

Will the battery charge at all off the 2.1V VMain? I assume it'd be slow as heck if it did, but since I'm not the greatest electrical engineer (aspiring CS/Math major here) I'm curious as to whether or not it would work.

Sucks that there are so many after-market PSUs for just about every other powerbook, but Blackbirds haven't got a thing. I can't help but think that somewhere there must be a PSU that can be wired up to the plug and made to work, but I'm not experienced enough to know how I'd find such a PSU... I guess I shouldn't ask the same question a zillion times, but do we know of any PSUs this can be done with? I remember seeing a thread with several reported successes of this method, so I'm just wondering how I'd go about doing that... would I just solder VBatt and VMain to the high lines and GND to Ground? What would I do with GND_SENSE in that case?

Or, if I were to go with the recap option: does anyone have a list of caps to buy?

 

[macosten]

Update!

I opened up my charger and swapped pins 1 and 2 (they were the red and orange wires in my charger). The computer now works, but I assume the battery will no longer charge.

This confirms TechKnight's assessment (and what tjjq said from the beginning ;p ).

So now I've got to just recap it, I assume. When I do, should I flip the wires back to their original positions or will they be fine as-is?

 

[tjjq44]

Better to flip back to original position since Vmain is 1.5A. With only 1A you may run out of power when using floppy drive with backlight at max intensity for example... and it will stress your power supply uselessly

 

[macosten]

Better to flip back to original position since Vmain is 1.5A. With only 1A you may run out of power when using floppy drive with backlight at max intensity for example... and it will stress your power supply uselessly

Alright. Luckily I used duct tape to seal my bodgework so while it looks like a growth it does work (for the time being) and I can just take the tape off to reverse it.

Do you suggest I just dremel the PSU brick open, or should I still try getting it apart with a flathead screwdriver (despite already having chipped the plastic)?

 

[jimjimx]

For what it's worth, I bought a IBM 16V 4.5A PSU on eBay, and connected the red & orange wires from the Powerbook cable to the positive, and everything else to negative.

My Powerbook 520 works just fine.

Although since the batteries are dead, I can't say if the charge circuit is fully working.....

Here's the one I bought:

https://www.ebay.com/itm/GENUINE-IBM-02K6657-02K6669-16V-4-5A-ThinkPad-AC-Power-Adapter-Charger-OEM/252818420883?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140107095009%26meid%3Ddf53b130a53e4c909fc21325c44da5dd%26pid%3D100040%26rk%3D1%26rkt%3D4%26mehot%3Dlo%26sd%3D263471999128%26itm%3D252818420883&_trksid=p2046732.c100040.m2060

--jim