PB G4 65W poweradapter broken, how to open it?

Question

Hi all,
The cable running from the poweradapter/charger (model no A1021, 65Watts) to my PB G4/800 has frayed where it leaves the poweradapter/charger cabinet, thus rendering the adapter/charger unserviceable.
I dislike throwing it into the bin, not for the money but for the sake of the environment. I am willing to give it a repair go, just cut off about, say, an inch and resolder the cable to the PCB. However, I cannot figure out how to open i.e. take apart the cabinet.
Anyone any hints how-to? Or is this one of those devices for which holds: opening means breaking?
Thanks for cooperation.
Sincere greetings from continental Europe,
Feike L Hoogenbos
iMac 20"-G5-iSight + PBG4/800   Mac OS X (10.4.7)  

Answer 1

Hello eww and all of you out there.
For eww: thanks for your reply.
About: “How to take apart the PB G4 65W poweradapter.”
I tried and it turned into a nitty-gritty enterprise.
I do not encourage anybody to go down this path, but if you insist, without modellers’ skills and gear, you end up with an adapter that is definitely beyond repair.
On the other hand, unserviceable it already was, so who cares?
In short:
You cannot: the white soap-box like poweradapters for Al, Ti PBks and (some) G4 iBooks, were (probably) never designed with any kind of ‘take-apart’ in mind, in other words: opening indeed equals breaking.
It is held together by several glued ‘males/females” (like the two fuselage halves in a Revell or Monogram model aeroplane or boat kit, remember that?), about half a meter or two feet of single-sided sticky tape and 20 cm’s or 8 inches double-sided sticky tape and about 15 grams or half an once of silicon-putty, the same kind of stuff you will find as a sealant where your bathtub meets the surrounding tiles.
The longer story, and remember, I started this all in with the intention (or assumption if you wish) it could be done in a reversible way. How wrong that turned out to be.....
To open the white box, I used a small-teethed saw-blade, only the blade!
Method: Sway the adapter’s feet out, clamp the adapter in a vice, claws covered with rubber sheet.
I carefully sawed in the ‘equatorial’ grooves. Hence the small-teethed saw-blade.
Look often how ‘deep’ you have sawed, stop when still the thickness of, say, a sheet of paper is left. Sounds difficult, but it is not, you will slowly see copper and aluminium colours appear.
You cannot saw in the groove at the side where the feet hinge and the cord leading to the PB, leaves the box. Deal with that later.
Okay, I had three equatorial grooves sawed out and yes, I could feel some ‘movement’.
By repeatedly sliding and prying a wooden wedge through the sawgrooves and twisting the halves realtive to each other I managed to get some more movement. That all makes quite unpleasant sounds.
After carrying on like this for about a minute or twenty, suddenly the two halves popped apart with a very nasty ‘tschack’ sound: two male/females broken and the two feet came apart.
Oh dear, I had disrupted the bond between one side of a two-sided piece of sticky-tape and the upper housing (that caused the ‘tschack’ sound). To the other sticky side: a piece of aluminium sheet (0.4mm or 0.015 inch thick).
That piece of aluminium sheet on its turn had a rectangular opening in it through which a larger piece of copper sheet (0.45mm or 0.017inch thick) could be seen.
The aluminium and coppersheets were connected in a somewhat strange way: partly electrically isolated by sticky-tape and silicon putty and partly electrically conducting, i.e. metal on metal contact.
The copper sheet appeared to be U-shaped, the electronics ‘wrapped’ inside.
As far as the lower housing concernes: the aluminium/copper contraption repeated or mirrored itself more or less.
Metal sheet(s) as thin as decribed and bonded to whatever by two-sided sticky tape and/or whatever sticky putty, any attempt to separate those without damage will be futile. No, you wouldn’t leave it overnight in a bowl filled with something like white-spirit, since that will definitely harm the electronics.
There I was: with wrinkled and bend aluminium and copper sheets and hundreds of silicon-putty chips around the place. But the adapter had been opened!
I started to wonder why the adapter looked like it looked.
I think the aluminium/copper sheeting serves as a heatsink and doubles as electromagnetic shielding, hence the somewhat strange looking conducting/non-conducting sandwich and cut-outs in the aluminium sheets. Eddy currents and so forth.
The adapter is of the switch-mode powersupply type and the mains transformer is a pot-core. This hints towards a quite high switching frequency, say something like 100kHz. It needs to be that high in order to convert 65Watts in such a small box without ending in a disaster.
This means, the apater is also a potential 65Watt jamming station - be it without a properly tuned antenna - hence the elaborate shielding with copper and aluminium sheets and strategically placed cut-outs, conducting and non-conducting spots.
I succeeded in taking the frayed cord out, again, not really easy, since room is at a premium in the adapter, but it can be done.
Next surprise: the cord between the adapter and the PB -a piece of coaxial cable by the way- carries only two conductors: a plus and a minus (an up and a down or how you wish to label it).
Will I be able to put it all back together again?
Eh, NO!
Ironing out the wrinkles in the copper an aluminium sheets, forget it.
With the wrinkles the whole assembly will be too thick to fit (cram?) into the the two halves of the soapbox.
And for those who think the whole thing could be glued together with epoxy, the silicon-putty residues are all over the box, so the epoxy or any other glue for that matter, will not stick.
It is as simple as that.
However, I learned a lot from this.
With sincere greetings from continental Europa,
Feike L Hoogenbos