View Full Version : LCD/flash problem w/ EX-S2

10-22-2006, 06:14 PM
I've got a 2 year-old EX-S2 that has quit working... sortof. It seems the high-current electronics aren't working. It turns on ok, all the software works ok, and with a bright angled light I can see the LCD is working, but the backlight LED isn't coming on. Also, the flash doesn't work and no images get recorded when a picture is taken. It seems like anything high-power (LCD LED, photoarray, flash) isn't working right. Occasionally, everything will work perfectly for a while (1-10 min). Then it won't. That is to say, all the problems are closely related (all or nothing).

I did some preliminary diagnostics:

The flash capacitor is charging ok, but the flash still doesn't work.
The battery is rated 3.7V, and has 3.79V across the +/- terminals, but the "T" terminal drops to 1.56V under load... whatever that means. The "T" terminal appears to have an internal resistance of 8.9kOhm.
The LCD backlight power terminals have 0V across them, as expected.

Anyway, I've checked a bunch of connections, but can't figure out the power circuit. I can't find any connection to the + terminal of the LED backlight, but I don't know where it is supposed to connect to anyway. Casio of course is no help. I was wondering if anyone has seen this before or has any ideas what to try. Does anyone know what the "T" terminal is on the battery? The battery is a Casio NP-20. Any help is greatly appreciated...

The "T" terminal is just a thyristor for overheat shutdown.
The LCD backlight power terminals are getting 3.29V
Does anyone know how to get datasheets on white LED backlights?
Do LED arrays fail short?
With LED backlight disconnected and removed, flash and photoarray still fail.