The Battery Leaked in this Electronic Tuner

I picked up a stack of these for ten bucks at a local music store.  They were all returned by customers who had problems with them.  Figuring a guitarist can’t have too many tuners, I sorted through them and got them all running.  Except this one:

The battery had leaked.  The ‘stuff’ that makes alkaline batteries work is (wait, wait, get ready for this…) alkaline in nature.  The caustic stuff, left on cadmium plated iron, was too much and the iron rusted.

Pretty nasty stuff.  Applying power directly to the circuit board, this tuner worked, so all I had to do was fabricate a new battery terminal.

This is a nickel-steel B string from an electric guitar.  It was too short to use anyway, but would be just fine as a springy, solder-able raw material to fabricate a new battery terminal.

With a little fiddling, I got it about the right shape and size.  Here, my handiwork is compared to the undamaged terminal at the other end of the battery stack.  My new terminal was shaped (crudely) as a cone-shaped spring, or close enough.

Here, we’re checking the newly-repurposed B string for a fit into the slot that will hold it when the batteries are installed.

The new battery terminal will be soldered to both sides of the circuit board here.

This is the solder joint on the other side of the board.

I think this crazy idea might actually work!

Tiny Phillips screws hold the circuit board against the LCD.  Connections to the LCD are made with Zebra strips.  What’s a Zebra strip?  Google it, if you’re interested.  And it has nothing to do with animals.

A fresh set of batteries are installed and the unit is checked.  WooHooo!

I had enough of these repaired that I gave them to other musicians, and I kept one in the guitar setup tool box as a spare.

This post just reinforces the old story about the electrical engineer who is the only person in town who will pull a five dollar transistor radio out of the trash and spend all day fixing it.  This project rates right up there with the transistor radio project, but at least it didn’t take all day!  I thought it was fun.

CONTACT INFORMATION – David Latchaw EE    281-636-8626