U-20 ZONE
U-20 ZONE
Battery DamageNote: In addition to the U‑20, these parts and procedures may also be applied when replacing the internal battery for the U‑220, U‑110, D‑70, Rhodes Model 660 and Rhodes Model 760 Synth

Well...... I finally replaced the internal lithium battery in my U‑20. I've owned my U‑20 for a looooong time and I've never had to replace the battery. I thought I would stay one step ahead of the game and replace the battery now before it leaks and causes any circuit board damage.

You can test the voltage of the internal battery without opening the case on the U‑20, U‑220, U‑110, D‑70, Rhodes Model 660 and Rhodes Model 760. How cool is that?!?



[ Warning: Test Mode does a 'Soft Reset'. Backup your internal Patches and RAM Card Patches before testing!! ]

U-20 Battery Test
   1) Enter TEST MODE by pressing [ PART ] + [ RHYTHM ] simultaneously to enter ROM Play Mode
   2) While holding [ MARK ] + [ JUMP ], press [ ENTER ] and the ROM version is displayed
   3) Hold down [ JUMP ] and press [ BANK 3 ] and the the BATTERY CHECK screen will appear
   4) If the battery voltage displayed is in the range from 2.8V to 3.5V, the battery is OK
   5) To exit TEST MODE, while holding [ MARK ] + [ JUMP ], press [ EXIT ]

U-220 Battery Test
   1) Enter TEST MODE by pressing [ JUMP ] + [ VALUE △ ] simultaneously to enter ROM Play Mode
   2) While holding [ MARK ] + [ JUMP ], press [ ENTER ] and the ROM version is displayed
   3) Hold down [ JUMP ] and press [ DATA ] and the the BATTERY CHECK screen will appear
   4) If the battery voltage displayed is in the range from 2.8V to 3.5V, the battery is OK
   5) To exit TEST MODE, while holding [ MARK ] + [ JUMP ], press [ EXIT ]

U-110 Battery Test
   1) Enter TEST MODE by holding [ DEC ] + [ INC ] while turning on the power (ROM version is displayed)
   2) Press [ DEC ] + [ INC ] simultaneously four times until the BATTERY CHECK screen appears
   3) If the battery voltage displayed is in the range from 2.8V to 3.5V, the battery is OK
   4) To exit TEST MODE, press [ DEC ] + [ INC ] simultaneously to cycle through the remaining tests

D-70 Battery Test
   1) Enter TEST MODE by holding the number button [ 7 ] while turning on the power (CHECK MODE is displayed)
   2) Press [ USER ] and the BATTERY & PROTECT SWITCH screen appears
   3) The battery voltage is displayed in Hexadecimal. A new battery = 53 and a faulty battery = 43
   4) To exit TEST MODE, power OFF the synth and power ON again

Rhodes Model 660 / Rhodes Model 760 Battery Test
   1) Enter TEST MODE by pressing [ EDIT ] + [ TUNE ] simultaneously to enter ROM PLAY MODE
   2) While holding [ PART1 ] + [ PART2 ], press [ WRITE ] and the TEST MODE screen is displayed
   3) While holding [ EDIT ], press [ BRASS ] and the BATTERY CHECK screen appears
   4) If the battery voltage is good, the message "OK" will appear
   5) To exit TEST MODE, while holding [ PART1 ] + [ PART2 ], press [ WRITE ]


PARTS
I buy all of my coin cell batteries from mouser.com
The battery is a CR2032 Lithium Battery (Mouser Part Number: 658-CR2032)

Luckily, there is already a battery holder installed. Less work! But... out of 12 synths, samplers and other devices, replacing the battery on a U-20 was one of the most difficult replacements I have encountered to date

I recommend buying a name-brand battery like Panasonic. Saving fifty cents to purchase an off-brand is, in my opinion, a bad idea. This battery is going to last a very long time so get a quality one without the need to worry about a cheap-o brand leaking and ruining your circuit board


PROCEDURE
Before you start, make sure you have saved all of your patches and tones to an external device like your computer.
* * * All of the internal patches and tones will be erased when the old battery is removed! * * *

Make sure you are wearing eye protection, are properly grounded and working on a static-free workbench or table.
* * * Please don't ignore the advice of eye protection, grounding and a static-free area * * *
The chances of finding new circuit boards or a new eye...... slim to none ;)

The replacement took me about 90 minutes from start to finish. I was taking extra time and being extremely careful to avoid any ESD nightmares. If you use care, it's possible to replace the battery without unplugging any cable assemblies.

(Refer to the images below)

1) Unplug the synthesizer!

2) Remove all screws on the bottom panel (five small screws and fifteen large screws). Leave the four rubber feet attached

3) Looking from the back of the keyboard, push the bottom panel forward about 25mm, lift upward and place aside

4) Remove four screws from the back panel which hold the MIDI circuit board in place (Remember the screw locations)

5) Remove one screw from the MIDI circuit board housing on the inside. Move the MIDI circuit board to the side

6) Remove seven screws from the main circuit board which is covered by an aluminum panel. Set the aluminum panel aside

7) Push the main circuit board forward about 25mm and flip it 90 degrees upward to access the battery and battery holder. Replace the battery with P/N: CR2032

8) When putting the main circuit board back in place, you will need to align it with the plastic RAM card housing attached to the back panel

9) When powering on, garbage will appear on the display after selecting a Patch so initialization is needed

10) Press [ PART ] and [ RHYTHM ] simultaneously to enter ROM Play Mode

11) While holding [ MARK ] and [ JUMP ], press [ ENTER ] for Test Mode

12) While holding [ JUMP ], press [ NUMBER 7 ]

13) Press [ ENTER ]

14) Press [ VALUE Δ ] to confirm

15) While holding [ MARK ] and [ JUMP ], press [ EXIT ] to exit Test Mode

16) Press [ KEYBOARD ] and [ SOUND ] simultaneously to return to Play Mode

17) Load internal Patches using a MIDI SysEx file with the Factory Presets


U-20 SMALL LOGO

U-20 Bottom Panel Removal
U-20 Cover Removal
* Leave the four rubber feet attached

U-20 Cover Removal

Remove seven screws from the main circuit board which is covered by an aluminum panel. Set the aluminum panel aside
U-20 Cover Removal

Push the main circuit board forward about 25mm and flip it 90 degrees upward to access battery and battery holder
U-20 Cover Removal




U-110 SMALL LOGO

U-110 Cover Removal

Unplug the synthesizer and remove 11 screws from the top cover (8 screws from sides - 3 screws from back).
A vertical battery holder is already installed... Hooray!

U-110 Cover Removal
U-110 Battery Location

U-110 Battery Location     U-110 Battery Location



U-220 SMALL LOGO

U-220 Cover Removal

Unplug the synthesizer and remove 11 screws from the top cover (8 screws from sides - 3 screws from back).
A vertical battery holder is already installed... Hooray!

U-220 Cover Removal

The U-220 battery location is nearly identical to the U-110. Refer to the U-110 battery location images above.



Safety Precautions and Disclaimer:
Modifications made to any factory stock equipment will always pose an element of risk. Sometimes mistakes are made which are irreversible. Improper soldering and handling of electricity can cause serious injury and damage the synthesizer. Use caution when handling static sensitive devices and the PCB. Make sure you are properly grounded, working on a static-free workbench or table and wearing eye protection during any soldering tasks. The author is not responsible for any damage or injury resulting from this DIY info. Use this DIY information at your own risk. And, I can't stress enough, the importance of wearing eye protection while soldering. That stuff flies everywhere sometimes!



U-20 ZONE