How do I repair a battery maintainer?

[Lonesome7.3]

I think I may have hooked the positive and negative leads on the wrong posts. So, I am guessing I blew something inside. It happens to all of us at some point. Anyhoo, I would rather repair than replace. Any idea what I should check first? How do I check it? I figured this would be a good chance to try out my new multimeter. It would be a good learning experience.

[JSchuricht]

Start with the simple things, look for anything that is burned or smells burnt also look for a fuse. Beyond that, you probably won't find a schematic so your not going to be able to see what connects where and calculate the circuit value. There aren't that many components so isolate each component and test it's value. The picture isn't vary good but the blue things are resistors, they have a color code on them that translates into a value. The black things are diodes, they allow current to flow in one direction only like a check valve. It looks like a pair of voltage regulators in the top left, everything else is too blurry to make guess. The transformer looks like it has 3 taps which are normally different voltages.

[Lonesome7.3]

Thank you for explaining that. I have a much better understanding now. Now, how to I check the other parts? The breaker checked out good.

[JSchuricht]

For resistors you need to use the resistance/ohm function on your meter. It looks like a horseshoe. Put a lead on each end of the resistor and compare the value to the value in it's color code. The issue you will run into is other components that can affect the resistance. The easiest thing I can explain is to just desoldier one side and test it. Same goes for the diodes but testing is slightly different. The diodes will only flow one way. Use the diode check function, bar and triangle on your meter. connect the leads to each end of the diode. One way you will get a reading the other you will not get a reading. If you get a reading in both directions or no reading at all then it is bad. For the voltage regulators you need to check the manufacturing info printed on them then build a test circuit.

It would be much easier with a schematic. You would plug it in and check various points from the AC in to the DC out and see where the calculated value was wrong.

[Lonesome7.3]

That was pretty easy to understand. Putting it to use might eb different but I loved the way you explained it. Thanks, I will give it a shot tomorrow.