I recently started using my 430EX11, here is what transpired over the course of 24hrs
I took my 430 flash unit out of the drawer opened the battery port to make sure it had fresh batterys, upon opening, I found some white corrosion build-up, I immediately discarded the batterys, cleaned the metal contacts and installed fresh set of batteries, turned the unit on and took about 15 shots, it worked great, I turned off the camera, turned off the flash unit, removed it from the camera.
Next day, I turned on my flash and noticed just a flicker, but no RED pilot light and unit was not working, I replaced another set of fresh batteries, just to be sure, tried turning it back on and again just a quick flicker and then the screen went blank, Im puzzled, is the unit damaged, no longer any good, or it it something I can either fix, or have someone fix, any help would be appreciated?
I would use a good, plastic and rubber safe, contact cleaner and be sure to clean the contacts that are inside the battery compartment and hard to reach. White ink erasers would well they are abrasive but will not harm the contacts It is possible the batteries leaked and have corroded an internal connection to the battery compartment unless you only saw corrosion on the battery door.
John, Thanks for the eraser idea, what i did was squeeze some lemon juice in a cup, applied it with a Q-Tip, I kept changing out the Q-Tips for fresh ones, as I could see the brown corrosion on the swabs, after about 8 swabs, I no longer had any corrosion comming off, so I let it dry over night, then I used an eraser very carefully for about 5 minutes, all the while cleaning the eraser head, it did the trick, been working ever since!
WD-40 on a cotton swab is very good at removing corrosion from leaking batteries and I have used it for that many times. Use plenty of WD-40 and allow it to work on the corrosion to loosen it, you do NOT want to apply a lot of pressure and bend the contacts causing them to lose their normal tension.
Position the flash in such a way that anything that comes off of the contacts will fall out of the battery compartment instead of getting somewhere else it shouldn't.