Notice to Powerbook Duo Users!

I just stripped down a powerbook duo 270c which has a busted screen.

I have noticed that the few electrolytic SMD caps this board has, are starting to leak, leave signs.

The large 100uf capacitors in the voltage regulator DC-DC circuits are the ones I am talking about. This is dangerous. Blow your DC-DC circuits, and its Game Over... Permanently....

Granted most of them are tantalum capacitors, There are still 7 aluminum electrolytics, 6 of those being in the Heart. Board has a heart-attack, it dies.... xx(

TIME TO RECAP

This requires taking the screen itself apart right?

Don't think so, I think he's talking about what looks like a small tank farm under the metal hump near the AC adapter lug on the Mobo, opposite the Modem Bay hump.

Precisely. But you do have to take the surrounding metal frame off to see/get to them, and that involves disassembling the entire thing (except screen).

I would rather warn everyone now, before it gets too late.

In case anyone wonders, they are 4 100uf 35v, and 2 100uf 25v. Something that every tech should have in a junk drawer. But there is a small clearance area, so low profile Nichicon caps are a must if you go radial. (luckily, i have a bag full of 25v. no 35v though. booo).

plus the 33uf 25v thats out there by itself.

Thanks for the warning. Yet another reason to stop stalling and recap my old PBs.

yea exactly. Not trying to be an alarmist or anything, but we cherish these older things, and if you say, blow a transformer, or a now discontinued SMPS switching IC on a portable logic board, How are we going to fix it? we arnt. Its going to be up to the engineers (like myself) to find a work-around to the damage in the power supply.

Anyway, When i disassembled this unit, i happened to notice it, like uh-oh... here we go... Its hard to say the conditions the Duo was in before I got it. its basically scrap now, but it does have a good logic board and stuff. Going to pull and save the inverter for another person that has a bad one.

So i cannot say if your caps are bad or good, but seeing what I saw, change them anyway.

Also, the 35V caps appear to be the 24v DC input filter. the other 2 appear to be the DC-DC filters.

Ok this seems like a silly question, is there a specific way of storing these or other boards until they are fixed? I'm not talking about temperature or humidity. If the boards were upside down, would the fluid just leak on the cap? Can gravity even make a difference on such a small object?

You know, those are questions that i cannot answer as I have no idea. lol.

you would figure if the logic board is upside down, it would leak on itself, but then again, the only place those will leak from is the bottom.

I'm pretty sure my 280c died this way, I recall hearing a ticking sound coming from that area..and that's all it ever did again xx( . I have very little soldering skills, I wonder how much one would charge if I brought the board in for cap replacements somewhere.

Ticking sound was from the DC-DC circuit. if it quit ticking and is dead, thats BAAAD news :-(

I just stripped down a powerbook duo 270c which has a busted screen. I have noticed that the few electrolytic SMD caps this board has, are starting to leak, leave signs

Click to expand...

Recapping the logic board is an easy job. The radial SMD capacitors in the LCD panel are another issue. Have a look behind the foil that covers the back of the LCD panel of a Duo 280c. The LCD panel is full of small radial SMD capacitors, some of them are already leaking or have high ESR readings.

Yep, the first thing that comes to mind would be to store them upside down.

Second thought would be take the MoBos out and place them upside down on an absorbant material inside a zip-lock bags for any mothballed mac.

Same thing x2 for Analog Boards.

Just storing Macs 0r PBs upside down and Compacts on their sides ought to help and probably can't hurt. What's the viscosity of the leakage? Will it well up and harden on the top of the cap stalactitically or drip? Anything has to be better than having goo spreading to additional traces.

Apparently I've been storing a couple of dozen various types of bare MoBos in the wrong orientation. :-/

Spreading goo on the silver sides of caps ought to be easier to spot than same on the MoBo when inspecting for re-installation or a pre-power-up inspection of a mac stored inverted.

Id rather just replace them and be done with it. period. But thats my philosophy.

Ya the caps on the LCD are another issue, but i covered that back on my PB 1XX models. I just used the same style SMD replacements because clearances are too small.

For the record, the ESR on SMD lytics wernt anything to write home about anyway.. thats why engineers use multitudes of them for one general circuit instead of 1 large one.

Some of us have too little (or none at all : ) experience in re-capping and much larger collections than would be likely to be recapped before one of the uncapped mobos springs a crap-out-n-kaput cap leak.

Eh. might have to join in on the recapping service i guess

Ok this seems like a silly question, is there a specific way of storing these or other boards until they are fixed? I'm not talking about temperature or humidity

Click to expand...

To avoid damage to the board, I take a photo of the board, remove all the capacitors and then clean it.

This way the board can be stored as long as want until you have time to replace the capacitors.

Have we got the "Definitive Guide" to re-capping developed here yet?

Start with the listing for every MotherBoard's Caps/Ratings/PackageType etc. and the Silk Screen Layer's designation for them.

After that we can add pics of each board with arrows pointing to the locations with the listing table for a single page printout . . .

I can do some of the graphics, it'd be a cool project for collaboration between our boffins, photobugs and graphics oriented comrades all over the world.

Maybe start with the MoBos trag has kits available for at great prices and then move on to parts listings/replacements from some online sources at reasonable pricing/policies for small quantities across the face of the planet.

I don't do Flash, but links to short videos of all the different replacement techniques for each Cap type would be great content as well.

I dont know, but I know mk.558 was starting on that by doing the SE/30 pic.

FYI, here's the "tank farm" that is spoken of:



Duo 230 (68030) foreground, 2300 background (PPC 603e). Also FYI, the 230 display connection will not hookup to the 2300 motherboard without some sort of adaptor. The 2300 display port is closer to the back of the unit (ie, away from an imaginary user) and is larger. Since the 2300 board was offered as an upgrade option, I imagine there was an adaptor ribbon of some kind. You can see the 2300 display connector in the hole to the modem-side of the CPU, the whitish vertical up pointed port. The 230's is right behind the large chip just to the modem-card-side of the CPU, and is a black connector that is perpendicular to the general orientation of the board (as where it is now, it's right near the reset button on the 2300's board.)

EDIT: I'm thinking I might do a write up on the Duo boards. They might be all identical, I mean there's just the 68030, 68040, 68LC40, and 603e, there can't be that much difference in the capacitors we are after. They do look big, juicy and could let off quite a BANG if they wanted to.

EDIT 2: I have the 230 board right in front of me here, there are:

2x 100µF 25V

1x 330µF 16V

3x 100µF 35V

1x "W1 33 25V" with a line over the W. Probably 33µF at 25V.

Not too bad. Soldering in the proper order (ie this one first, then this one, then that one) is probably advised, lest you box yourself in :-x As for the 2300 and the others, well, I'd have to ask our fellow soldiers for that, since I don't have a 210, 250, 270 or 280. As for my 2300, well, I'd have to take my 2300TB apart all over again, removing the CPU stiffener isn't exactly fun...but not as bad as the iBook G3 600MHz on up...