OT:- charging camera batteries

Modern battery charging circuits monitor temperature to tell when the battery is charged and adjust charging rate so that might be the purpose of the T terminal. It might be possible to build a circuit that will charge without using that by keeping the charge current low enough to avoid battery damage even when it's fully charged but this increases the charging time dramatically.

Your assumption on cost of repairs is not a safe one. I have a Fuji camera. I was quoted £130 for repairs and I could buy the same model (by then superceded) from Fuji's website ex dealer stock for £90 or brand new for £110 I think. In the end I repaired it myself as I had nothing to lose by trying.

Russell

Based on my experience with Sony, it would be cheaper to buy a new camera in most cases. They offer repair but usually at a price near MSR.

Many makers do sell stand alone chargers for charging the battery outside the camera. Buying one of those would be your best choice.

Wes S

Tim Fuji do a fixed price repair on digital cameras, it sounds expensive at first (a friend was quoted £130 for a 6900) but they refurbish it and give a year's warranty on it (not just on the repaired part) so if you particularly like the camera, it's worth having it done. Martin

Thanks Martin, I'll look into that. Funnily enough, I have a 6900 which has gradually lost all its functions, & now just works as a basic point & shoot job. I was quoted that sort of money by a local shop a couple of years ago to get it sorted, decided not to bother. This is an F810, nice little camera but I'd look at what an equivalent replacement would cost before spending much on it.

Cheers Tim

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Unlike NiCad and NiMH, there is no safe 'trickle charge' current level for a fully-charged Li-Ion battery. You must use a voltage limit (4.2V per cell, give or take a tenth to trade off lifetime cycles against power per charge). Charge termination is based on current dropping below some threshold after it's been held at 4.2V for a while, or in cheaper models based on a timer (terminate an hour after reaching 4.2V, say). You need a current limit as well - around 0.25 to 0.5 C is typical (0.25 to 0.5 A for a 1 Ah battery).

If you're lucky, constant-current with no voltage limit will just ruin the battery capacity; if you're not so lucky it'll get hot, puff up and then 'vent with flame'.

Use a proper Li-Ion charger for similarly sized batteries or a circuit designed specifically to charge them. RC model shops should have "universal" chargers for Li-Ion which let you set the current level to something appropriate for your battery, but not all support charging single cells.

Tim

No2 Son bought a Sony Mavica CD-300 in Amsterdam last year, and the dealer sold him an all-singing charger for Li-Ion batteries with various adaptors etc., as the original charger wasn't with it.

I took it over and I have a Sony bench charger for M and L batteries so no problems.

The universal types are still on the market (mine sold) look out for:

Ansmann Digi Charger or on ebay:

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Thanks Tim

I didn't check that Li-ion were the same as Nicad and NiMH - it looks like I should have done.

Russell

Tim Aut> Russell wrote:

Thanks Peter and others. I was on the point of ordering something of that nature, then just thought I would check the box the camera came in - 'just in case'. There was no charger, but there was a cradle which takes power and USB via a single socket into the base of the camera. I've never bothered with it, as I use a card reader to get the pics onto the computer. Thought it was worth a try, so plugged the charger unit into it, dropped in the camera and...hey presto, the charging light came on, and has now gone off (hopefully) indicating a full charge. The fault must, it seems, just be a broken wire between the coaxial power socket and the internal charging circuit.

Thanks again

Tim

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I went back to the 6900 while the little camera was out of action, and played with it a bit more. The problem was/is that anything other than auto point & shoot was totally unpredictable, and especially the macro function was unavailable. There are little buttons for things like Macro, Flash mode, delay timer, sequence shooting etc. You could press any one of these buttons and it might do nothing, or it might activate that function or a totally different function. I did wonder whether the symptoms could be a result of one of tese push buttons malfunctioning, maybe always 'on'. After some fairly dedicated button pushing it seemed as though things were getting back nearer to how they should be, I could even fairly consistently call up the macro mode - until pressing something else confused the system again. Does anyone here know roughly how these things work, and could suggest whether this sounds like an electrical (switch) problem, or a faulty chip etc? If the former, I might even have a go myself. The latter, I'll leave well alone.

Thanks

Tim

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I would suspect that the buttons work by having a grid of PCB tracks that are polled by rows and columns by the imp inside the camera. The buttons themselves will have conductive rubber ends that short two tracks together when pressed. So that the imp sees that when he puts volts in on row 1 he gets volts out on column 3 and that means go into macro mode etc.

If the camera has ever got wet, it's possible that there is crud on the tracks. Taking it all apart and carefully cleaning the PCB with alcohol and doing the same with rubber contacts on the buttons, may well restore functionality.... or not.

It's worked for me with television remote controls.

Mark Rand RTFM

Thanks Mark. I've not been aware of it ever getting wet, but there's a little chromed trim on the lens which is showing signs of rust, so maybe it has. I've come to the conclusion that the main culprit is a thumbwheel under the main mode selector knob. This is supposed to give fine adjustments to various things, dependent on mode, but it behaves erratically & won't give the full range in any mode. Whether the thumbheel drives a pot, or a ring of switches, or a little 'generator', I've no idea, but operating it is almost guaranteed to upset all the other buttons.

Cheers Tim

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FWIW, having attempted to disassemble compact cameras in the past, your chances of successfully re-assembling the beast afterwards is likely to be small even if you do get to and fix the fault. They cram the bits in extremely tightly. So I would recommend either taking up the Fuji fixed-fee repair service(as mentioned elsewhere in this thread) or flogging it on the Bay and getting a new one (I never cease to be amazed by the prices that cameras sold for spares or repair fetch!)

Worth noting that a cheap replacement option is to buy refurbs from Fuji themselves - see:

Thanks Tony, that's actually where I got my little Fuji after deciding not to spend the money on repairing the 6900.

My experience of DIY camera repairs is a bit like yours , I'd only try if I thought there was nothing to lose. The 6900 is actually an 'SLR style' camera, so there might be slightly more room to play with. As it is, some fairly persistent messing about with it has brought it back to a more useable state, whereas last time I messed with it it seemed to get steadily worse.

Cheers Tim

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