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Electronic Theatre Controls Inc

Express - How to Fix Intermittent Switches


The information in this post is provided to assist in troubleshooting. Perform work at your own risk. ENSURE ANY POWER FROM DEVICES HAS BEEN DISCONNECTED BEFORE SERVICING ANY EQUIPMENT. 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.


Express buttons are not responding or are intermittent. 

Description/Explanation of Issue

The cause of the problem is a bad connection inside the switch, usually corrosion on the hinge side of the internal switch mechanism.


  1. Test the Face Panel using the Diagnostic Disk to confirm which switches are bad and later confirm that they have been fixed.
    1. Use a computer with a floppy drive to copy the face panel diagnostic file (FACE.BIN​) to a floppy disk.
    2. Turn off the console, and then insert the disk.
    3. Turn on the console and low the disk to load.
    4. Select the "Face" test and press [Enter].
    5. Test all of the buttons and faders.  Wiggling can help find intermittent issues.​​​​​
  2. Press the button several times.  This often will break through the corrosion and allow the switch to work correctly.
  3. If the switch is still intermittent or non-responsive,  cleaning the switch with rubbing alcohol is the next step. 
    1. Turn off the Express console.
    2. Remove the black plastic keycap using a thin tool with a L-shaped end.
    3. Put a generous amount of rubbing alcohol over the exposed white switch surface and then press the switch many times so that the rubbing alcohol gets into the switch and reaches the corroded parts.
    4. Use forced air to clear out the liquid rubbing alcohol. (Eye protection and proper ventilation are recommended)
    5. Turn the console back on and test.
  4. If the switch is still intermittent or non-responsive, the best solution is to replace the switch:  S278 (no LED), S281 (with LED)
  5. If a new switch cannot be obtained or the switch must work, the switch might be made functional by scraping off the corrosion from the inner switch mechanism.
    1. Follow this link for procedure with pictures - EXPS Cleaning Intermittent Buttons.docx
    2. Turn off the console.
    3. Remove the white plastic switch cover.
    4. Remove the copper contact. (CAUTION: It may fly out in your face)
    5. Clean / Scrape away the corrosion on the copper spring contact and the contact points inside the switch.
    6. Re-assemble the switch.

If no switches fail the face panel test, a bad Trackpad could be the cause of the data entry or control issues.  Run the Trackpad test (TRACKPAD.BIN) following the same steps as the Face Panel diagnostic disk.

  • Once the Trackpad test has been loaded, press [Track] and [Record] to track and record the input of the Trackpad.
  • A bad Trackpad will have a false press holding when pressure is removed, and/or it will not track finger motion accurately.
  • A bad Trackpad should be replaced by an experienced technician, but it can be unplugged internally in an emergency.
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