C860 Schematics

[louigi600]

however, a number of people with charging problems have found that there's an internal protective fuse which can blow, and can be replaced with care. search forums for "fuse"?
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Thanx to all who contributed so far.
Yep I checked and I've the 0.63A fuse blown. The one on [a href=\"http://www.tyrannozaurus.com/files/ChargingChipFusePic_2.jpg]here[/url].
To get there one must open up Z and take out the mobo because that one in on the side facing the keyboard.
I hope I can find a replacement ... if anyone has any hints they are wellcome.

[pelrun]

Check the thread I originally mentioned; the photos are no longer available from it (you have those now) but the fuse availability stuff is still in there.

Quick guide - Koa Speer has them, unfortunately it's a coin-toss whether they'll actually respond to your sample order or just ignore you.

Farnell will sell small quantities (at vastly inflated prices) of 0.75A fuses in the right size, but they aren't ultra-fast-blow. I used one of those successfully; but I'm not sure if it's any better than a wire link. I'm *not* going to test it; my 860 is working

[louigi600]

Quick guide - Koa Speer has them, unfortunately it's a coin-toss whether they'll actually respond to your sample order or just ignore you.

They are free samples so you cannot complain .... same for mucrochip ... sometimes they ignore. But what the hell sometimes you can get 5 free pic microcontrollers.

Farnell will sell small quantities (at vastly inflated prices) of 0.75A fuses in the right size, but they aren't ultra-fast-blow. I used one of those successfully; but I'm not sure if it's any better than a wire link. I'm *not* going to test it; my 860 is working

No using non ultra fast blow fises is a no go. You risk damaging other ccomponents before the fuse blows. It's difficult enough replacing a 2 solder pad SMD component without propper soldering/desoldering station ... immagine what fun you can have soldering one of those chips with many  pins all smaller in size that the solder pad of the resistors/capacitors/fuses.
I'd rather buy an external charger than try a wire bridge or a non ultra fast fuse.

[pelrun]

The SMD soldering is easy. Putting the Z back together is the hard part.  

I don't know what the risk is for using a lower-specced fuse; it may still do the job fine, and it's better than never getting it fixed at all. I just opt for NOT reversing the polarity on my Z ever again; I've always got the time to test an unknown supply even when I don't

[louigi600]

The SMD soldering is easy. Putting the Z back together is the hard part. 

Really for me opening and closing the C860, without leaving trace, is no big deal at all.
I've taken pictures and will put up a "tips n trics to opening Z Cxx0 without leaving trace" on my site. I've done it, for other reasons, on my C 760 and the case is the same (appart the colors). For me the nightmare is desoldering/soldering those 1.6x0.8 mm midgets ... so close to the other components too !!!
People are telling me that I can slide paper underneath the side I'm desoldeting. I'm unsure if it will work because the paper wil get partially burned with the heat and will become very fragile ... but I will try ... and make tests on scrap hardware first.
Any other tips and tricks for smd soldering/desoldering are wellcome.

I don't know what the risk is for using a lower-specced fuse; it may still do the job fine, and it's better than never getting it fixed at all.

Thanks to all the help comunity has given me I have confirmation that koaspeer will ship me free samples of the correct rating fuses ... just waiting for them to arrive

I just opt for NOT reversing the polarity on my Z ever again; I've always got the time to test an unknown supply even when I don't

It was not a matter of testing in my case:
I share the tip of a reversable polarity power supply with my extra external battery pack.
One day I just clumsily plugget the tip upside-down ... and there you go ...

[pelrun]

Any other tips and tricks for smd soldering/desoldering are wellcome.

Don't desolder the old fuse, since it's open-circuit anyway. Just piggyback the new fuse onto the old one.

It was not a matter of testing in my case:
I share the tip of a reversable polarity power supply with my extra external battery pack.
One day I just clumsily plugget the tip upside-down ... and there you go ...

That's pretty much how everyone does it, I think. No matter how sure I am about getting those tips right, if I unplug them and don't have time to get my multimeter out to test them again, I just don't use my Z on it. I fried a laptop and my Z in my car learning that the hard way; I eventually repaired both but I'm not going to be so lucky next time...

[Drake01]

I share the tip of a reversable polarity power supply with my extra external battery pack.
One day I just clumsily plugget the tip upside-down ... and there you go ...
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I bought a dedicated power supply for the Z.  I didn't want the be sharing anything, because that might create the situation you encountered.  And I glued the adapter tip on so that it wouldn't accidentally come off, which would provide me with the opportunity to reassemble it backwards.  I used to use a multimeter to make sure the polarity was correct, but now that it's glued on I don't have to worry about it.

[louigi600]

The pictures and tips are up on my home page.
Click "Zaurus" on the left and "Z Service" on the top.

Still waiting for the samples to arrive ... I'll add a picture of the finished soldering job when I have it finished.

[speculatrix]

one of the biggest problems with the tube connectors is that so many things use them, so you have to be sure when plugging in the Z that you haven't grabbed the wrong one!

[louigi600]

I got fed up waiting ....
anyone can send me a couple of those fuses ... or tell me where I can get one from my 5500 I'm willing to sacrifice untill I receive the samples ?

[louigi600]

Koaspeer sent me a wierd email this week from which I assume that I will never get the samples (although they did confirm at first that they would send).
Noboby actually answered my help request as to where to get such a fuse from my 5500 and nobody was able to send me a couple so that I could get going.

This is what I did: I desoldered from a broken MOBO the smallest fuses I could find.
I got a few fuses that are slightly bigger (around 2.0x0.8x0.6 LxWxH) but if you place them on the side they are become the same width as the 0603 package ... and just 0.4mm longer.
(the 0603 is package base footprint in inches 0.06 x 0.03 which is roughly 1.6 x 0.8 mm)

This way I was able to solder it over the burned one.

What is worrying me is that I'be no idea what the fuse rating is ... it could be anything from 0.5A to 3.5A and it could also be non fast blow: this means that I'll most likely run ito real trouble if I connect an inverted charger again. But on the other hand I got pissed off waiting.

Koaspeer have proven to be very  unprofessional ... anyone else wanting samples would be better off ither buy small quantity at ilflated price or get samples from some other company.

[Capn_Fish]

Your Z lives, I take it?

If so, congrats.

[louigi600]

Your Z lives, I take it?

If so, congrats.
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Yep ... it lives and charges again.