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active battery drain or ???

wrench45us

wrench45us

Guest
Aug 26, 2011
1,325
295
#1
I bought a used Zon RTK with the knockoff no name electronics rather than the early models that had EMG pickups and preamp.

Based on the shape it was in when I got it, it hadn't been played in a very long time, so I wasn't too surprised when the active electronics died after about a month.
I replaced the battery with a battery I took out of a pedal, so it wasn't exactly fresh, but last night about a month after the first die off, the same thing happened again.

Now it's possible the battery I replaced it with was old and so this is just a coincidence or is it possible the battery is being drained when the bass isn't plugged in?
Neither battery was exactly dead when the active electronics faded based on the 9 volt battery across the tongue test. I don't have a voltmeter, but there's still considerable juice in that battery. Another possibility is that circuit requires a high minimum voltage to work.

Anyway to know what's going on?
When it dies, it does fast -- like 5 seconds so there's not much warning.

the other option is to think about replacing what I assume are pretty standard form factors and preamp.
I have opened it up and it's a rather disappointing sloppy soldering job.
 
#4
You'll probably buy a cheap multimeter for not much more than a couple of batteries. Then you can see if it's drawing current while unplugged, and also how much current that is.

You'll also be able to test your batteries to see what voltage it is when the preamp starts to distort.

All this info is a huge help when trouble shooting a preamp.
 
#5
where would I tap to see if current is being drawn when the bass isn't plugged in?

can I plug a cable in and tap the other end?
Given that pedals can drain with just a cable plugged in and not attached at the other end, I'm unsure where to test for drawing current while unplugged.
 
#8
just watched that vid. I'd recommend
using the current setting not voltage otherwise you are measuring the voltage drop through your meter. I guess that still tells you that the circuit is on, but really the current draw is the info you need.

running a chaos pad and a few pedals
from a single 9v is pretty silly tbh. the more current you draw from a battery, the less performance you get. and it reduces logarithmically not linearly.

oh, and resting an alligator clip connected to a positive battery terminal on a piece of shielding (presumably connected to earth) is asking for trouble.

the vid is clearly made with the best intentions but sometimes I wish luthiers wouldn't try to be electronics technicians...
 
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#9
I gave it the visual inspection last night. I'll have a multi meter in a day or two,

Visually I do see three leads coming into the output jack.
None of them are really contacting each other. One wire is white inner wire to the left and the outside is coaxial wrap that goes to the center spade. That wrap is pretty weak and frayed and not the greatest soldering job, but it is connected. The wire opposite from the white is red and that's a good connection.
So visually not great, but nothing readily apparent.

Thanks for the information.
 

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