Kala KA-SCGE flattening 2032 batteries

Hi everyone. This is my first time here as new ukulele player.

Just before Xmas 2020 I treated myself to a new Kala Concert KA-SCGE ukulele. This has a tuner/pre-amp module labelled UK-300TR. It uses two CR 2032 cells.

After a couple weeks of playing using just the tuner, the tuner started playing up and the LB (low battery) light came on, so I installed some new Duracell 2032 button batteries. All was well. I'm always careful to turn off the tuner before putting the instrument away. Currently I'm only playing acoustically, not plugged in to an amplifier.

Now, after about three weeks, the LB light is coming on again, and my voltmeter tells me that the combined voltage of the two cells is 4.6v, instead of 6v. The tuner still works but surely the batteries should last much much longer than this?

I presume that even when off, the electronics module consumes some current, but I'm unable to confirm/measure this with my meter.

Obviously, I could take it back to the shop where I bought it, but I wouldn't want the whole instrument replaced, since it's set up exactly as I want it and I like the sound. Besides, we're in lockdown right now so there would be logistical difficulties.

Right now, I'm removing the batteries when I'm not playing, but even that is awkward and only an interim measure.

Please does anyone have any information, suggestions, or ideas?

Thanks, Bob

I don't have that instrument, but most of my guitars and ukuleles with pickup and preamp have a micro switch in the output jack. When you jack in, the switch powers up the preamp. Sometimes the switch gets stuck on (depressed position) and it draws power. I usually mess with it and clean the jack, the switch pops back out. Once I had to replace the jack (micro switch jammed due to rust) but that is rare.

On the other hand, I own clip-on flip on tuners that run down the 2032 battery after several months of not being used, so it could be the dad burn tuner as well.

Thanks for an excellent suggestion.

I used an endoscope to look into the socket and the microswitch seems ok, but it could still be making a permanent connection to the power. I guess I'll have to figure out a way to connect my meter in series with the batteries so I can see how much current gets drawn with the tuner on and off, and a lead plugged and unplugged. Sigh.

With four mandolins and now a uke, none of my clip-on tuners ever get left unused for months!