C860 Charging Problem (not Battery)

[cgrieves]

My c860 is not turning on.  I didn't think this to be a battery issue until I read your post.  Even when my Z is plugged into the wall outlet, it will not turn on.  Do you think that could still be a battery issue?
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The C860 seems to need a bit of charge in the battery before it will turn on, even while on the AC adapter. If you are plugging your adapter in and the charging light is coming on but not charging the battery, then I suspect you may have the charging problem. Trying another battery or using an external charger is the only way to be sure....

Also see if you can get into the service mode (press D & M while turning on).

[bethanyb]

Thanks for replying.  I wasn't able to get into the service mode.  Have you had to replace your battery frequently?

I'm not one who likes to replace rechargeable batteries.  But hopefully a new battery will solve this problem.

[ThC]

don't want this thread to die neither ^^
my c860 is taking dust ... too bad :/

[mle]

Yeah, me neither... I have now played with my 860 for a week, and only sad thing is that it doesn't recharge battery...

I was measuring it today for a while. First, I recharged battery back to ~4.2V with external charger. Then I connected all three terminals to 860 with wires to measure voltages. Voltage dropped down to ~3.44V, with or without charger. Even when I measured voltage without battery, it was near that value too. I was thinking to give it a little extra kick from another external power supply, like 4.2V directly to pins, but didn't try that one yet.

Otherwise my 860 is working nice. I can use it as long as I wan't with AC connected, it recognizes charging, turns background light bright, and cacko says that it's charging. But when I unplug AC, charge in the battery drops to the same value it was before connecting AC.

I need to do some investigations, I'm quite sure that charging circuit is not totally dead, but there's something strange.

Oh yeah, and even with fully charged battery, I can't get more than 220 (2.8V) main batteryAD in service menu. This starts to be a challenge to get it working.

Maybe it's those capacitors, need to open it tomorrow.

Edit:

I measured voltages once again. Batteryvoltage drops down to ~3.75V when connected (with or without AC), without battery voltage in terminals is 3.14V. Doesn't matter whether batteryswitch (one that closes the "backdoor", you know.) is on or off, voltage is the same.

Now I'm trying to find suitable screwdriver (why girlfriends never has any decent tools, goddammit) to open my Zaurus.

[maslovsky]

OK, guys, sorry for some long delay, but here are the pictures of the two fuses that need to be replaces in most cases to fix charging problem:

http://cacko.oesf.org/downloads/fuses/Main...use%20pic_1.jpg
http://cacko.oesf.org/downloads/fuses/Char...use%20pic_2.jpg

Pictures are huge, so I'm only posting links here.

And some explanaition form my friend:

Main protection fuse F804 (pic_1.jpg) protects the whole board from overvoltage.
Its nominal is 2 A. It gets burned in 95% of cases of overvoltage or wrong AC adapter polarity.

Charging chip fuse F813 (pic_2.jpg). ALWAYS BURNED. Nominal is 0.63 А

There are other fuses on the board, which may theoreticaly get burned but this has never happened yet.

[EDIT by Varti] The two images are not available anymore. I have found one on them on the Tyrannozaurus' site, I have attached it on this post; unfortunately, the other image is still missing: https://web.archive.org/web/20070715013809/...gingCircuitC860

ChargingChipFusePic_2.jpg:

[mle]

Yes, you were right, charging fuse was burned. Main fuse was ok.

Now I gotta find 630mA fuse in 0603 case.

Edit:
Seems that it's quite hard to find fuse from here in Finland. Farnell doesn't supply 630mA fuse in 0603 (1.6x08mm) case, digikey does, but minimum order is 5000 pieces.

Wickman does manufacture those, so I sent email to them, waiting for reply. 0805 (2x.1.25mm) is little bit too big...

[mle]

maslovsky: Could you do me a favour and ask your friend, where did he buy those fuses, especially that 630mA one.  Since I have gone thru almost every electronic store here in Finland, and I could only find that 5000pcs reel... :|

[maslovsky]

maslovsky: Could you do me a favour and ask your friend, where did he buy those fuses, especially that 630mA one.  Since I have gone thru almost every electronic store here in Finland, and I could only find that 5000pcs reel... :|
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We took them from another dead Zaurus...  Even if we bought them it wouldn't help you since we live in Moscow, Russia

[mle]

We took them from another dead Zaurus...  Even if we bought them it wouldn't help you since we live in Moscow, Russia
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Damn.  Well, even coming to visit Moscow would be cheaper than order 5000 pcs reel from USA.  

Well, I have to keep on searching. Thanks for your fast reply.

Edit:
[a href=\"http://www.littlefuse.com/]Littlefuse[/url] seems to manufacture almost that kind of fuses (680mA), and they does provide sample orders too.
Koa Speer also seems to make them. They also have sample order form...

[cgrieves]

Wow, thanks Maslovsky, I think you have just made an awful lot of clamshell owners very happy indeed, including me! in fact I haven't felt so happy since we won the ashes

I will see what I can find in terms of components. 0603-packaged 2A fuses are very easy to find, but so far I haven't found any 630mA, only 500mA and 750mA.

If anyone finds's a retailer stocking these, please post here and I'll pay to buy a load of them, then we can send them out to whoever needs them. Likewise if I find a source I'll post it here.

Cheers!

[mle]

If anyone finds's a retailer stocking these, please post here and I'll pay to buy a load of them, then we can send them out to whoever needs them. Likewise if I find a source I'll post it here.

Cheers!
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Like I said in my previous post, [a href=\"http://www.koaspeers.com/]Koa Speers[/url] makes them, and they do provide samples for you. Im waiting my shipping early in the next week...

mle

[Nataliya]

If anyone finds's a retailer stocking these, please post here and I'll pay to buy a load of them, then we can send them out to whoever needs them. Likewise if I find a source I'll post it here.

Hi Cgrieves, I was wondering if you've managed to find the fuses - I'm in Woking and desperate to get my hands on them too... I can't for the life of me find anything on the Koa Speers / Littelfuse websites    Could you guys let me know where you got the fuses or perhaps post a direct link on where they are on those sites? Pretty pleeeaaaase .

[seinfield]

I have an idea, you can buy a normal fuse (a cristal fuse) of 630 ma or 500ma (if you dont find the 630ma fuse).
Break the cristal being carefull to dont miss the conductor, then solder both sides of that conductor to your zaurus where the small fuse goes, taking care to dont touch any other pice of metal or circuit around.

I think that can works!!!

Regards

[mle]

Hi Cgrieves, I was wondering if you've managed to find the fuses - I'm in Woking and desperate to get my hands on them too... I can't for the life of me find anything on the Koa Speers / Littelfuse websites    Could you guys let me know where you got the fuses or perhaps post a direct link on where they are on those sites? Pretty pleeeaaaase .
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Nataliya, you can find correct fuses from [a href=\"http://www.koaspeer.com]Koaspeers[/url] website:
Products -> Circuit Protection -> Thin Film Chip Fuse (TF) -> And there they are, TF16SN0.63 and TF16SN2.00

You can use the link "order samples" directly, and use those part numbers I gave.

I also got my samples from Koa Speers, I ordered them about ten, so please let me know if you need, I have few extra here which I could send.

mle.

[mle]

I have an idea, you can buy a normal fuse (a cristal fuse) of 630 ma or 500ma (if you dont find the 630ma fuse).
Break the cristal being carefull to dont miss the conductor, then solder both sides of that conductor to your zaurus where the small fuse goes, taking care to dont touch any other pice of metal or circuit around.

I think that can works!!!

Regards
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Hi Seinfield, I was thinking this way also when I was quite desperate to find correct fuses. Problem is that those fuses are 0603 size, 1.6x0.8 mm and the layout is quite tight, so adding self-made fuses there may not be easy...

Anyway, I got some samplefuses from Koa Speers, and I also have few extra fuses of both of them, so if there is a need, I can send those extrafuses.