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Full Version: HELP! C700 does not display anything anymore
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jchung
Ok, last night I decided to swap out the G2 screen protector. I always carefully unscrew the panel and insert hte screen protector from there, and there have been no problems.

After swaping out the screen protector the C700 doesnt want to start anymore! :cry:

I think I killed the display.. but how?? I've done this procedure before without problems...

please help!! sad.gif
jchung
I bought this off of ebay from someone that went to japan to get it. Can I send it to sharp to get it fixed? do you think the warranty is still available?
jchung
OK

I looked at it again and it seems like some sort of connection is loose. I can barely see the display but it's still there..
zbones
It sounds like the screen is working but you have no backlight. I have never taken a clamshell apart, and by the sounds of it I don't want to.

The obvious things to check are the wires going to/from the light unit.

Do you have a multimeter?

Peter.
jchung
I could get my hands on one..

what should I be looking for?
zbones
Not really sure, as I don't want to dimantle mine to test a working one.

A simple continuity test to check that there is a connection through the wire to the backlight would be helpfull.

Unless it's been subjected to shock, I think it's unlikely that the light has gone, it's more likely that the wires have come loose, this could be :-

1) dry joint,
2) wire detached (should be obvious),
3) wire broken inside the insulation.

You could also check the resistance of the backlight itself to see if it is "open circuit".

If it can be powered on with the backligh exposed you could check vor a voltage across the backlight to see if the z is supplying a voltage to it.

I am not an trained in eltronic repairs, but I have fixed several devices using the above method.

The other common problems with things not working after they have been dismantled is trapping a wire in the case, putting a screw through a wire, some have mini switches that need to be closed when the case is closed.

Somebody who has dismantled one wil have more of an idea as to what check for.

Peter
jchung
I didnt get a multimeter but I did open it back up. I checked all the wires and they look solid. The unit will turn on if the cover and screw are not on..

there is this one part that I'm a little concerned about. One of the screw threading got stripped so the screw doesnt really hold tight. There is a small PCB board with solder dots aligned in a ring around the screw hole. This looks like it's supposed to contact with a metal piece of the swivel screen. The solder on this is kinda worn out. Would this affect anything?

I'm gonna buy a product called plastex that is supposed to fix threading on plastic products. Hopefully that will work on this stripped thread problem. Should I try to re-solder those dots??

Thanks
zbones
QUOTE
there is this one part that I'm a little concerned about. One of the screw threading got stripped so the screw doesnt really hold tight. There is a small PCB board with solder dots aligned in a ring around the screw hole. This looks like it's supposed to contact with a metal piece of the swivel screen. The solder on this is kinda worn out. Would this affect anything?  


If it turns on when it's dismantled, then it can't be relying on a ground from a screw as an anti tamper mechanism, as it wouldnt work when it's in bits when the contact is disconnected.
At least you know there is no major problem as all the bits work. It still could be a dry joint/broken wire that works when it's in some postions but not others.

Or it could be that when the screws are in place it is shorting out something that shouldn't be.

Without knowing what should be connected (if anything) when the case is closed it is hard to say. I would tend to favor a dodgy wire based on what you have said.

Case point: My mouse worked sometimes but not others. I found it would work if I bent the wire in a certain way while using it. The copper inside the insulation had broken and bending the wire made it connect.

Solution: cut the wire 2 inches from the mouse, and reconect the wires. This resulted with a shorter cable, and a fully working mouse. This was on an Ataris st, when a new mouse cost over £30 ($40 us).

You don't really want to keep taking it to bits as this will probably only make things worse, but if it is still in bits, try and bend the wires into the same position it would be when fully assembled, or waggle the wires one at a time (gently). if the screen goes off you have found your culprit and will need to replace that wire.

What's your soldering like? Replacing a wire is fairly simple, but if you are not used to soldering then you could end up making things worse either by bridging across two components, or "cooking" the joints and damaging the board or other components.

You may find that if you put it back together it will work fine. Once it's all screwed in place things aren't gong to move anymore.

I would offer to help, but I doubt you are local to me.

Peter.
jchung
I have no idea what I can do w/ my C700 now.. I still dont know what's causing the problem..

I dont know of any places that sell spare parts otherwise I could buy replacement parts if necessary..


:cry:
zbones
Do you have a local friendly repair shop?

If it is only the baklight that is screwed it may be a simple repair.

The main problems with repairing modern electronic devices is getting hold of custom ic's and manuals.

If the backlight has gone south, then they may be able to substitute it with a simillar unit.

My local friendly repair shop does not charge if they cannot fix something within a reasonable cost, if they can fix it it is a minimum of £25 (about $40)

From what I have read, the sharp repair service is pretty good, but will not ship to/from places outside of Japan.

Sharp USA will not get involved or offer to help you, fortunately faults on these units seem to be very few and far between.

If all else fails, you may get a reasonable offer on ebay from somebody who has toasted the cpu but has a working backlight.

Again, this is a rare problem so advice will be hard to find.

Peter
daffy2405
QUOTE(jchung @ May 4 2004, 02:43 PM)
I have no idea what I can do w/ my C700 now..  I still dont know what's causing the problem..

I dont know of any places that sell spare parts otherwise I could buy replacement parts if necessary..


:cry:


hello, (I'm french,sorry for my very bad english wink.gif )

I have a same problem with my zaurus(SL-C860). I unscrew the panel , and there have been no problems.the display work,but no backlight !!

jchung>Your Zaurus it is repaired ?

Thanks,
daf smile.gif
sebastien79
QUOTE(daffy2405 @ Jul 18 2004, 10:21 AM)
QUOTE(jchung @ May 4 2004, 02:43 PM)
I have no idea what I can do w/ my C700 now..  I still dont know what's causing the problem..

I dont know of any places that sell spare parts otherwise I could buy replacement parts if necessary..


:cry:


hello, (I'm french,sorry for my very bad english wink.gif )

I have a same problem with my zaurus(SL-C860). I unscrew the panel , and there have been no problems.the display work,but no backlight !!

jchung>Your Zaurus it is repaired ?

Thanks,
daf smile.gif
*



Hello, (my old name is daffy2405,my new sebastien79)

I finally repaired (after 6 month !!)my zaurus.The problem came from one defect component (self or fuser ?)
My english is not good thus I will not explain more.
I put a picture.
Click to view attachment

Sebastien79 biggrin.gif (thanks Gilles) biggrin.gif
Nightwing
QUOTE(sebastien79 @ Feb 27 2005, 10:15 AM)
Hello, (my old name is daffy2405,my new sebastien79)

I finally repaired (after 6 month !!)my zaurus.The problem came from one defect component (self or fuser ?)
My english is not good thus I will not explain more.
I put a picture.
Click to view attachment

Sebastien79  biggrin.gif (thanks Gilles) biggrin.gif
*


Hi, just wanted to express my thanks. I had to take the display on my 760 apart to get the old screen protector off (installed by the vendor). Once I was done, I had the same problem -- no more backlight. ohmy.gif After I saw your post, I tried connecting the two points with a screwdriver and the light was back. Long story short, my 760 now has a jumper in the display.

Many thanks for sharing your fix and picture! You helped get me back on my Zaurus and the price was definately right! biggrin.gif

All the best,
alan
sebastien79
QUOTE(Nightwing @ Jul 7 2005, 02:45 AM)
QUOTE(sebastien79 @ Feb 27 2005, 10:15 AM)
Hello, (my old name is daffy2405,my new sebastien79)

I finally repaired (after 6 month !!)my zaurus.The problem came from one defect component (self or fuser ?)
My english is not good thus I will not explain more.
I put a picture.
Click to view attachment

Sebastien79  biggrin.gif (thanks Gilles) biggrin.gif
*


Hi, just wanted to express my thanks. I had to take the display on my 760 apart to get the old screen protector off (installed by the vendor). Once I was done, I had the same problem -- no more backlight. ohmy.gif After I saw your post, I tried connecting the two points with a screwdriver and the light was back. Long story short, my 760 now has a jumper in the display.

Many thanks for sharing your fix and picture! You helped get me back on my Zaurus and the price was definately right! biggrin.gif

All the best,
alan
*




Thank you very much! wink.gif

My repaired zaurus always functions very well since February ! No problem with backlight ! smile.gif

it is a pleasure of seeing your zaurus repaired!

Thanks,
Seb
jchung
Wow.. i'm glad someone found a fix to this! I havent check this thread in so long.

I'm going to try this fix this weekend to see if it works! Thanks!
jchung
QUOTE(sebastien79 @ Feb 27 2005, 05:15 AM)
QUOTE(daffy2405 @ Jul 18 2004, 10:21 AM)
QUOTE(jchung @ May 4 2004, 02:43 PM)
I have no idea what I can do w/ my C700 now..  I still dont know what's causing the problem..

I dont know of any places that sell spare parts otherwise I could buy replacement parts if necessary..


:cry:


hello, (I'm french,sorry for my very bad english wink.gif )

I have a same problem with my zaurus(SL-C860). I unscrew the panel , and there have been no problems.the display work,but no backlight !!

jchung>Your Zaurus it is repaired ?

Thanks,
daf smile.gif
*



Hello, (my old name is daffy2405,my new sebastien79)

I finally repaired (after 6 month !!)my zaurus.The problem came from one defect component (self or fuser ?)
My english is not good thus I will not explain more.
I put a picture.
Click to view attachment

Sebastien79 biggrin.gif (thanks Gilles) biggrin.gif
*



Thank you Sebastien79! I tried it today and it works now! I just need to solder it. biggrin.gif
guylhem
Hello

I have a similar problem happenning, although there may be more than one thing happening.

Did you try to mesure the resistance of the "fried component" ? mine has 0 ohms, and the part you suggest to shunt also have 0 ohms.

This should means everything works as expected on that part. Before I make a shunt, I think I should ask

Guylhem
sebastien79
QUOTE(guylhem @ Apr 25 2006, 09:44 AM)
Hello

I have a similar problem happenning, although there may be more than one thing happening.

Did you try to mesure the resistance of the "fried component" ? mine has 0 ohms, and the part you suggest to shunt also have 0 ohms.

This should means everything works as expected on that part. Before I make a shunt, I think I should ask

Guylhem
*


Hello ,

My solution is perhaps not ok for all the problems of display....

There is perhaps another problem ?...

my "fried componant" was open (not 0 ohms)...

You see that the screen is ok without backlight ??

@+
Seb
PS:Sorry for my very bad english.... unsure.gif
guylhem
On peut continuer en français si tu veux. Comment as-tu diagnostiqué le problème ? Pourrais-tu me donner un avis sur ce problème de backlight ? Je ne connais pas assez ce genre de trucs.

Je suis à Toulouse, mais je passe la fin de semaine à Paris si tu veux voir le Zaurus en question

Guylhem
sebastien79
QUOTE(guylhem @ Apr 25 2006, 11:28 AM)
On peut continuer en français si tu veux. Comment as-tu diagnostiqué le problème ? Pourrais-tu me donner un avis sur ce problème de backlight ? Je ne connais pas assez ce genre de trucs.

Je suis à Toulouse, mais je passe la fin de semaine à Paris si tu veux voir le Zaurus en question

Guylhem
*


ah ça fait du bien de parler français wink.gif wink.gif

Comment ton problème est apparu ?

Est-ce que tu vois quand même si l'écran fonctionne bien sans le backlight ?

C'est qui c'est passé dans mon cas.Je voyais bien que l'écran fonctionnait en le mettant à lumière.J'ai donc commencé à vérifier les nappes etc ...sans succès.

Ensuite j'ai démonté l'écran.Avec une alim j'ai mis une tension aux leds de rétro-éclairage pour voir si elles fonctionnaient.

J'ai vu que les leds étaient OK.J'ai donc suivi le signal à l'envers :des leds vers la carte où arrivent les différentes nappes de la carte mère du zaurus.

En suivant le signal je me suis aperçu qu'après ce composant plus rien !! J'ai donc essayé de le shunter et la suite tu la connais...

En fait je pense que c'est soit un fusible ou une petite self anti-retour.

Le problème m'est arrivé en voulant nettoyer l'écran du zaurus en le démontant sad.gif au remontage plus de backlight , c'est soit un problème d'éléctricité statique ou un truc du genre car j'ai touché la carte avec les doigts...

Voilà,
PS:Je suis en Vendée , donc à moins que tu viennes en vacances dans le coin.....
RE-PS:T'es Guylhem de pdafrance ?
@+
Seb.
guylhem
C'est apparu subitement, en remontant le zaurus. J'ai fait comme toi, vérifié les nappes etc. Pour ce qui est de l'alimentation des leds de l'écran, combient leur faut-il ? j'ai mesuré qu'il y a 0, et en suivant le signal j'ai bien vu un composant juste a coté de la prise (petit marron) avec 6v de ddp à ses bornes, mais lorsque je le shorte, la led de charge clignote en orange, c'est tout...

Je vais essayer de balancer du courant au leds , mais j'aimerais savoir combien d'abord :-) et quelle pola, etc...

Idéalement, tester avec un inverter qui marche pourrait bien aider...

PS: oui je suis guylhem de pdafrance :-) D'habitude je joue + avec les 6000 mais la je voulais faire un nouveau hack...
sebastien79
Si ma mémoire est bonne tu peux mettre 12 volts sur l'ensemble (pas sur une !!)des leds sans risques.J'ai pris une alim stabilisé et j'ai monté progressivement jusqu'a temps que les leds s'allument.

Pour la polar si tu as un multimètre avec testeur de diode c'est l'idéal , sinon suis ta polarité en partant de la nappe sur la petite carte.

Si je me souviens bien le six pattes à côté de la capa (voir photo) est le convertisseur CC-CC multiplicateur de tension qui permet à partir de la tension de base du zaurus d'obtenir une tension assez forte pour les leds (je sais plus quel voltage mais ça doit être de l'ordre de 30-40V)

Par contre tu dis que quand tu shunt le "fameux" composant la led de charge clignote ??

@+
Seb.
guylhem
Salut

Pas de testeur de diode sous la main, mais je bricolerai ça pour tester le backlight.

Pour le composant que je shunte, ce n'est pas celui de ton schéma mais celui qui est tout à côté du connecteur de cable venant du zaurus. Ensuite, exactement, il fait clignotter la led de charge batterie, ce qui confirmerait son role de capa et qui mettrait le problème plus loin.

Puis-je te demander un grand service : ouvrir ton zaurus et faire quelques mesures de tension sur les composants entre les 2 connecteurs (celui qui vient du zaurus et celui qui alimente les leds) qui sont sur la photo , en deux temps : *lorsque l'écran fonctionne* (des voltages) et lorsqu'il ne fonctionne pas (des résistances)

Je n'ai pas la documentation du convertisseur CC-CC multiplicateur de tension. Si je pouvais avoir quelques mesures de tension, ça pourrait me donner une idée sur son rôle dans l'histoire...

Guylhem
sebastien79
Bien que ça m'enchante pas trop de réouvrir la partie écran sad.gif , je veux bien prendre quelque mesures smile.gif . Par contre vu mes dispos actuelles ce sera pas avant la fin de la semaine prochaine...

Envois-moi par mp ton mail.

@+
Seb.
frank7d
Hi Sebastien

ton travail m'a aid beaucoup. J' ai un sl c1000 akita et j'ai russi de trouver le fusible pour le backlight. (plus facile, mme "1.25A" imprim cot du fusible".

your work helped me a lot. I have got an aktita sl c1000 and I managed to find the fuse. (There is even printed 1.25A on the board)

frank
sebastien79
Salut frank ,

Heureux que cette astuce puisse encore dpanner du monde wink.gif !!

@+
Seb.
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