Repairing a solar desulfating charger.... (unknown diodes)

[ja421]

A friend asked me to look at his solar charger & we figured it would be something had burned up... well;  it turns out it got wet and rusted a bunch of parts out -- the resistors were easy enough to identify (is there a way to tell how many watts a resistor is by it's diameter?  The most like like 1/4w but one is 2.8mm in diameter..)

The problem I have is identifying some diodes.  I was able to get some marks off the diodes, but can't locate replacements...
As you can see by the images, it's pretty rough; still need to pull some jumpers and a couple more resistors; but we got all the broken parts off....

Marks on the broken diodes are "F 41 48" which I could identify, but the other is labeled "5 C3" (or "C3 5")

It's a 12v 15w charging system; any ideas if replacements are easily found or w/o schematics is it just a crap shoot & not worth it?

[edavid]

5C3 is a 5.1V 500mW zener diode.

[ja421]

5C3 is a 5.1V 500mW zener diode.

Thank you.

[CJay]

I'd take a wild stab in the dark and guess the 4148 diodes are 1N4148 (possibly the most common diode in the world?)

[Enigma-man]

The resistor at the top of your pic is a 1/2 watt.  If there were resistors smaller than the 1/4 watt
they would be 1/8 watt and going the other way 1 watt, 5 watt, etc.
You might want to get some 99% Isopropyl Alcohol and Q-Tips to clean any residue from the top of the board.
The diodes are likely 1N4148 as JClay mentioned and it won't set you back much to replace the diodes and resistors.
If it still doesn't work, some of the transistors may have shorted out.

[ja421]

Thanks.  decided to give it a quick try. Going to solder in some diodes & resistors jut at the ends & see if it works.  If it comes back to life, great, if not; I can easily salvage the parts.   I have everything but the 5.1 .5w zener & the 1/2 watt resistor.  I'll use a 5.1v zener & a 1/4 watt resistor to see if it powers on; if it doesn't; I'm most likely giving up on it.  upon using a microscope, just about all the leads are really pitted/corroded, so it may be a fools errand in not replacing everything.  At that point, I don't think it's worth the headache of re-tuning it w/o any info on how.

I appreciate the help; I'll post if it the quick try was a success or not.