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Old Jan 23, 2004, 5:16 AM   #1
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Default Battery reversal test

Hi,

I accidently made a mistake when loading fresh NiMH AA 2100mAH batteries into my Olympus D-100. I put them with the wrong polarity.
But now, even when putting the batteries correctly, the camera is still dead.
I have no idea how this is possible ... If I remember well, this is not the fisrt time I'm making this mistake. And the camera always survived ... Maybe it is caused by the increased short circuit current available from the newest NiMH AA cells ...
Or maybe it was just casual, the camaera went dead for another reason ...

I have a second Olympus D-100. Alive. Then I decided to repeat the operation with this second one. I deliberatly put the same two NiMH AA 2100mAH batteries with the wrong polarity... and the second camera went dead also. No heating from the batteries. No heating from the camera. Died in silence ... I tried many times putting new batteries with correct polarity ... The second camera remains dead.

So, my stereo setup is now completely dead.

In order to avoid the same disaster to other people, may I suggest to Steve to do a battery reversal survival test. Preferably with freshly charged NiMH AA 2100mAH models.

And I'll appreciate a lot if somebody can tell me if there is a fuse or something approaching to be replaced on their D-100 model. I don't blame Olympus at all. The D-100 model is old and at the time of design, 2100mA cells were not available.

Alternatively, I'll appreciate a lot if somebody can point me a service manual for the Olympus D-100. I have electronics and soldering skills. I already dismantled one of the two D-100, I measured 2,75 Volts on the red/black miniature connector, all to do is to tell me how to get that sleeping beauty alive.

Regards,
Steph from Belgium
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Old Jan 23, 2004, 3:59 PM   #2
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Don't know your camera but here are some thoughts (&guesses!).

I guess your camera uses 2 AA batteries, so the terminal voltage of a pair of charged NiMh's should be around 2.8 volt.

Presumably it's too dead to try a 'reset to factory default'? If you are measuring around 2.8v on the external power jack, I wouldn't expect this when a jack is plugged in because otherwise external chargers will try to put in lots of mA, as well as running the camera. The jack socket usually has a back contact which breaks the batt supply when a plug is put in. So the first thing I'd try is put in an empty plug, are there any volts on the plug, if no can the camera be powered with an external supply? Have you been poking things in the external power jack and damaged the back contact, which carries the batt supply through to the camera?

If no start looking for faulty diodes and circuit fuses. Diodes aren't always used at these low batt. voltages, I think they use a fet and sample the current/voltage, registering a lockout when things go wrong. Have you tried removing the batts completely, shorting out the batt terminals in the box with a croc lead and leaving the camera a day before trying fresh re-charged batts the right way round? If it comes alive you can expect date and any custom settings to be lost. If there is a control fet on the dc side and the camera is deliberately powered off, it might take time for the fet to lose its charge holding it off.

Good luck -VOX
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Old Jan 23, 2004, 4:36 PM   #3
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Hi VOXMAGNA,

I feel you might be right especially about a MOSFET gate-source capacitance that doesn't discharge properly this time. But why this time especially ? Remember that the camera survived battery reversal beforehand ...

And this happened with the two cameras ...

I will try letting the two cameras sleep one full night with the batteries replaced by a short circuit.

I'll tell you tomorrow how the things went ...

Maybe you can help me pointing a web page showing more details about how manufacturers manage to avoid one series diode voltage drop. Yes, indeed I rougly see how a MOSFET can be used, but what about the parasitic drain-source diode ? Still not sure ...

Maybe touching the PCB area with a wet or conductive cloth can help discharging the gate capacitor. The problem is to locate the part of the PCB that is involved.
I'll check twice if I see power MOSFETS close to the red/black connector.

P.S.
***
When I wrote the red/black connector, I wasn't speaking about the external 3V minijack. I was saying about the internal connector that goes from the battery compartment to the camera PCB.


Thank for your reply,

Regards,
Steph
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Old Jan 23, 2004, 5:56 PM   #4
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Yes, indeed I rougly see how a MOSFET can be used, but what about the parasitic drain-source diode ? Still not sure ...

Can't help you with a direct link, I just come across these things, it probably wasn't even a camera, and I thought, so that's how you avoid the diode drop with only a few batt. volts. I vaguely remember also reading about the problems of designing low drop out battery regulator IC's along similar lines. I think switching fets designed for low Rds on was the method.

Your cameras might just be very simple. I wonder if they invert the dc batts up to say 5 volt, or have you got really lean and mean low voltage circuits? Sounds like you could still try the external supply then? I've read a few posts where cameras that only worked tethered were found to have faulty back contacts on their dc in connector. If the cameras work on external then you definitely know you've got a battery supply steering problem or an internal fuse somewhere looking like a normal surface mount device.

You won't find service manuals for cameras. The brave jump in with their magnifying glasses, microscopes and sub miniature tools in a clean environment, taking macro shots at each step ( for others to benefit) then if success follows, become hero's for all owners with similar cameras. Of course if you are brave enough to admit failure, can't even get inside, break even one part or lose something, they'll say 'we told you it was impossible' you should have returned it for repair!

http://www.digsys.com.au/S602Z/S602Z.html

Who Dares Wins!

VOX
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Old Jan 24, 2004, 2:49 PM   #5
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Hi VOXMAGNA,

... I will try letting the two cameras sleep one full night with the batteries replaced by a short circuit....

No luck ! None of the two cameras went alive.

Without a service manual, I feel this repair quite difficult.


Summary :

Olympus D-100 Digital camera (branded as C-1 in Europe). Designed to wishtand battery reversal, but two cameras died after battery reversal. 128Mb smart media was present. No heat. No visible damage on PCB. Smartmedia still OK. Backup battery disconnected to ensure total "reset". Left one full night with batteries replaced by short circuit. Also dead if powered from external DC jack.

Still dead ...
Any help or idea welcome.

Steph
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Old Jan 25, 2004, 6:44 AM   #6
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..........Also dead if powered from external DC jack.

That suggests its upstream from the power 'in' then.

I doubt you'll ever get a manual, manufacturers don't encourage DIY repair - they like to keep their secrets good and bad inside the box. There's a favorite phrase over here 'no user serviceable parts inside'!

If you've managed to get to the circuit board level then try to identify components connected to the batt. connector and external jack. On most cameras the on/off switch (because of current demand) is often not a simple switch at all, but a dc voltage ladder sending signals for each function to a simple voltage decoder across a ribbon to a solid state switch.

Sorry, but cunning and perseverence might win, also see what you can get from sending some emails. But first write: 'I reversed the batts and the camera refused to work again as per the specification' What's wrong?

If you are very lucky, they might say something like 'hold down this button whilst switching on the camera and all will be well' (unless the default menu on repower becomes Japanese!) Regards VOX
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Old Jan 25, 2004, 3:53 PM   #7
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Hi VOXMAGNA,

... as per the specification ...

Well, people from Olympus Belgium tech tell me "it should resist battery reversal", but they want me to send the two AA NiMH cells and also the charger ...

Cells are 2100 mAH from GP POWER BATTERIES (Gold Peak Group) and charger is the GP POWERBANK SMART 2 (Gold Peak Group). To me they are first quality products, well designed, and to me there is no question about compatibility.

Olympus tech in Belgium tell me that they will extensively test this combination and if it doesn't get approved, they will issue a service bulletin about AA cells and chargers.

What do you think about ?

Regards,
Steph
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Old Jan 26, 2004, 7:39 AM   #8
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............Cells are 2100 mAH from GP POWER BATTERIES (Gold Peak Group) and charger is the GP POWERBANK SMART 2 (Gold Peak Group). To me they are first quality products, well designed, and to me there is no question about compatibility...........

I think they are clutching at straws, to give you the run around, More info on how the battery supply gets to the camera circuitry is what you really need. But then they want to see the whole picture and not leave anything to chance. I don't suppose there's some physical means to stop power up when the batts are put in wrong way round? I have found some batts physically a tight fit compared to others - this is a bit of a long shot.

If you really want to test their claim, find a shop with the same camera and try AA Alkaline non-rechargeables - That's real 1.5 volts! The only thing I can think of, is if they are sensing batt reversal BEFORE controlling a switch on device, it might have a lower threshold and might not work if the batts were in a low state of charge - BUT you said yours were fully charged.

Can you try them out on one camera first and ask for a full report on the fault?
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Old Mar 31, 2004, 11:35 AM   #9
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Hi,

This post is to inform that I've sent one Olympus A-100 back to the Olympus Technical Centre here in Belgium.

It came back one week later with a delivery note saying that a fuse was replaced and that the battery compartment was changed.
They don't say if the repair they have made makes the camera survive to a battery reversal ...
Surely not, as the new battery compartment has a new sticker explicitely showing where to put the negative side of one of the two batteries ...
Apart from this, the camera was cleaned, it looks like new, and (but maybe I'm wrong) the white balance is more accurate. Could it be they upgraded the software ?

Techs at Olympus, you are are serious guys. Thanks !
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