Damaged LCD display

[eluminator]

One of the seven segment digits on my C Crane charger lost 3 of the segments. I cleaned the charger by wiping with a slightly damp paper towel with a small amount of soap. I wiped it again with a slightly damp towel with plain water. When I plugged in the wall wart, the three segments were missing. The rest of the display is fine.

Unplugging it for a while has no effect. I tried a "lamp test". I found if I pressed anywhere on the display with my finger, the icons and segments near my finger would all become visible momentarily, except the three missing segments. They seemed to vanish forever.

Does anyone have any ideas?

I'm not too happy about buying another one, because I own more chargers than I can count. Unfortunately this one is indispensable because it's the only one that displays the status of all my batteries from AAA to D.

 

[JSWrightOC]

Most LCD displays utilize either an elastomeric connector interface between the glass substrate and the PCB or a plastic ribbon with conductive carbon traces, glued or clamped to the PCB and the glass. If yours is of the elastomeric type, you might try carefully disassembling the LCD from the PCB (typically using a metal retaining bracket) and cleaning the glass substrate, elastomer, and PCB connection with alcohol, then reassemble. Make sure you squeeze the parts together when reassembling, or else it won't make proper contact.

Again, this is only from experience with LCD displays of this nature. The C. Crane charger might use a completely different method...

 

[eluminator]

Thanks JS. I'll take a look at it when I get the time. I hope the 91% isopropyl alcohol from the drug store will do.

 

[eluminator]

Well I tried and failed. The LCD unit was held to the board with a steel frame. I disassembled it, cleaned everything, and reassembled. No change. I even flipped the rubbery strip from end to end. Still no change.

I suspect the LCD itself, though it could be the PCB. I cleaned the whole PCB and I cleaned the whole LCD. With a toothbrush and alcohol.

The LCD is a 4 layer sandwich. The middle two layers are no doubt glass. The two thin layers on the outside seem to be plastic. They are all glued together somehow. Maybe some water seeped in there. There are some kind of conductive traces on the glass ledge that make contact with the rubbery strip. Where some of these conductive traces enter the glass sandwich I see something that might be corrosion, but it's where I can't get at it.

I'm pi$$ed. If I had dropped it or abused it, that would be different. Apparently I can't clean it without destroying it. And as far as I know, there is no other brand that can replace it.

 

[Saaby]

Call C Crane...

 

[JSWrightOC]

there are actually five layers of material, plus the LC fluid in the middle. Starting from the top you have the front polarizing filter, top glass substrate, LC fluid, bottom glass substrate, back polarizing filter, than the reflective backing.

It sounds like the LCD itself is damaged (judging by the mention of the corrosion) and yes, that is very thin vapor deposited metal on the glass. That forms the conductors and electrodes for the segments. It is possible your overall cleaning of the charger etched the few-atoms-thick metal right off the glass. /ubbthreads/images/graemlins/frown.gif

Sorry man.....hope you have some luck with C Crane...

 

[TheFire]

Is it a standard connection? You might be able to find a drop in replacement for the LCD if you looked around.

 

[eluminator]

I believe these LCD's are custom made. They have lots of icons that are just for this charger.

Actually I've just ordered the Saitek charger that Saitek sells directly. Here's my reasoning, which I think you will find unassailable.

1. It costs twice as much as the C Crane.
2. It seems to work just like the C Crane according to the specs I once saw on the web, but can't seem to find now.
3. I'm stupid.

You can't argue with that, can you?
Actually I'm hoping they fixed the spring anchor problem, and maybe they made a few minor improvements. This one will also charge 9 volt batteries, though I've never been able to figure why I'd want a 9 volt rechargeable.

 

[vcal]

The Saitek charger is exactly like the one sold by Rad.Shack about 4 years ago for $49.95 Unfortunately, R.S. discontinued it. I still use it today (along with my CCrane unit)..and yes they are electronically the same.

p.s.-the rechargeable 9V. works well with the Pal series of pocket lights and a few other things.

 

[JSWrightOC]

I too have an old RS charger. After taking it apart, I noticed that hte printed circuit boards have the "Saitek" logos printed all over them. /ubbthreads/images/graemlins/grin.gif

One note though, the positive contacts are recessed too much for some cells which have short button tops. A blob of solder on each fixes this, however. /ubbthreads/images/graemlins/smile.gif

The LCDs are custom made. Even if you determined the original manufacturer (Varitronics Limited, Optronics, etc.) they probably would not be able to sell you a display. I tried this with a vacuum fluorescent display made by Futaba in an RCA VCR. It was a valid Futaba P/N, but it was for an internal run destined to the manufacturer of the VCR.

 

[eluminator]

I guessed it was like the Radio Shack.

After thinking about it, I remember noticing quite a bit of rust on the metal frame that holds the LCD to the PCB. The charger sits on the kitchen counter for months at a time, and I'm guessing it's been unknowingly splashed with water in the past. Cleaning it may have been the straw that broke the camel's back.

I have some generic green 4500 mAh C cells bought from an outfit north of the border that have short buttons that won't make contact in any of my chargers. C Crane, Rayovac PS3, etc.

That pi$$es me off too. The overall length is about standard, but the cell itself is longer and the button is shorter. So they could squeeze a few more mAh in there and win the capacity race. Then suckers like me that wanted to buy the highest capacity get stuck with unusable cells.

By the way I've noticed my NiCad D cells are a tiny bit longer overall than my alkalines, and my NiMH D cells are a tiny bit longer that the NiCad. Just enough to make me modify the C Crane charger to allow them to fit in.

I guess there is no end to this oversize cell madness. Only if everyone returned theirs would the manufacturers quit doing this. And that won't happen. I'm too lazy.

 

[JSWrightOC]

Sorry to hear you are having troubles.

The mod I did on my RS charger works perfectly. Even some of their own AAs have too-short nipples that make charging unreliable. The only problem is, depending on the height of the solder mound, you might defeat the reverse-polarity protection. I always look at the cells anyway (and I'm sure every other CPFer does too) to make sure I'm putting them in right, but things like this are there to protect people who don't know any better. /ubbthreads/images/graemlins/jpshakehead.gif /ubbthreads/images/graemlins/twakfl.gif /ubbthreads/images/graemlins/whoopin.gif