Sometimes at rehearsal with my band, we’ll play with a click to focus on rhythm. We use an old BOSS DR-770 drum machine set to a simple accented rimshot pattern. This certainly works better than running a metronome app on the phone. All good, until the DR-770 battery dies…
The crappy picture quality here reflects my state of mind at the time.
In this low battery state, the unit is unusable. The battery is only there to retain user data, so the unit could have been designed to still function with a low battery. But no, they chose to brick the machine until the battery is replaced. Yay BOSS!
According to the BOSS knowledge base, the battery is not user replaceable. However, it uses a standard CR-2032 battery in a simple clip-mount, so it is really quite trivial to replace. No soldering required, just a screwdriver and a steady hand.
First, flip over the unit and remove all six screws on the back, and lift off the back.
Then, gently pull the I/O board forward (so the jacks are free of their holes in the chassis), and then pull up to expose the battery hidden underneath.
A thin strip of black retaining tape holds the battery in its clip. Peel this tape up on one side, but don’t remove it all the way, since it can be reused after installing the new battery. Then use a spudger or other prying tool to push forward on the battery from the back, and remove the battery from its clip.
The battery is a standard CR-2032. I bought a 5-pack on Amazon for a few bucks. Slide it into the clip at the front, and then press down on the back of the battery to seat it in the clip.
With the new battery installed, fix it in place with the retaining tape, and then lay the I/O board back into its original position (feeding the jacks back through the holes in the chassis). Replace the back and the screws, and you’re done.
On powering up, you’ll find that the unit will be reset to factory state. You’ll need to rebuild any custom patterns.
If you are a Dr. Rhythm power-user and create your own custom content, then be sure to back up your data regularly via MIDI dump
Good thing our needs are pretty simple and we didn’t lose much!