Coincidence or did I fix this battery charger?

[Tim R]

My neighbor asked me to look at the battery charger for her leaf blower. It was dead, no lights came on and the battery wouldn't charge. I don't have electronics skills but I guess I could take it apart and look for a fuse or something obvious. It was an 18V Ridgid, if that matters.

So find my tamper proof Torx set, open it up and look. Youtube says the transformer is weakly attached and these always break the solder joint to the board. Nope. But the board looks like it has a hairline crack - no, it rubs off, it's like a very fine line of spider silk. I pulled several of these off.

Then I plugged it in thinking I might be able to trace voltage but it started working again and it charged the battery fine.

I know it's always better to be lucky than good, but did that material make a difference, or was it just coincidence that taking it apart and handling it did some good?

[ohg...@gmail.com]

It's intermittent which means it will quit again. Could still be bad solder, a PC crack, or an intermittent controller IC or other component.

[Peter W.]

> I know it's always better to be lucky than good, but did that material make a difference, or was it just coincidence that taking it apart and handling it did some good?

Ridge Tools tends to make decent stuff - however, they have their fair share of cheap Chinese crap as well. Some wild thoughts in no particular order:

a) That 'spider silk' may have been some sort of incipient Tin- Whisker. Cleaning it off may have removed a current bridge interfering with the proper function of the charger.
b) You jostled the innards just enough such that an intermittent/cold-solder/damaged trace/broken connection remade itself.
c) The receptacle where it was plugged in at her house was off. I have come across any number of receptacles on a wall switch next to an entry door to turn on a lamp or some-such. People forget and blame the device. We have three such in our summer house.

I expect that you should go back to the board and check *EVERYTHING*, and re-solder anything even faintly suspicious. And anything with any weight on it, depending only on solder to be secured, might do with a dab of epoxy or similar (NOT RTV silicon, unless rated for electronics!) to reduce strain.

Peter Wieck
Melrose Park, PA