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Electronic Theatre Controls Inc

Changing the SRAM Battery in Expression 3 while the Console is On


The information in this post is provided to assist in troubleshooting. Perform work at your own risk. If you do not feel comfortable performing the work, please contact us or your local service center. Be aware that ETC and its Affiliates are not responsible for any damage or injury caused by service of our products by anyone other than us or our authorized service providers, and such damage is excluded from the product’s warranty.


Can I change the SRAM battery in my Expression 3 while the console is running?

Description/Explanation of Issue

Yes, the SRAM battery, which is a CR2477 battery (ETC part number: BT137) can be changed while the console is powered on. If you suspect your SRAM battery is dead, you may lose your show file if your console loses power or gets turned off. This is especially important if you do not have a backup of your show file.


  1. Open the Expression 3 by turning the bottom two knobs on each side of your console, and then lifting the face panel.
  2. Find the CPU tray, which will be located in the center of the console, and unscrew the five screws holding the top of the tray. Inside will be the CPU board. The battery will be located near the edge of the CPU board closest to the front of the console.
  3. Remove the old battery, and replace it with the new one.
  4. Place the top of the tray back in it's original position and screw it down using the five screws that we removed in Step 2.
  5. Close your console by lowering the face panel and tightening the knobs on each side of the console.
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