Q: The LCD display on my Symphony talkback base is blank after someone fiddled with it. What can I do?

The LCD contrast is set in the factory. The user can adjust it further using the Symphony’s front panel controls and LCD display prompts (if visible!). However, if the front panel contrast is adjusted and left in a condition where the LCD contrast is so weak, the display becomes blank and nothing is visible. This makes subsequent front panel correction near enough impossible. So what do to do?

If your Symphony is still within its 12 months warranty period please contact Technical Support at W&D for advice before proceeding..

The following is a description of a method to make the display visible enough to allow front panel contrast correction.

1)      Remove the mains supply to the Symphony.

2)      Take the top lid off the Symphony base.

3)      Locate the front panel PCB. (It doesn’t need removing).


4)  Solder a wire to this point. The other end of the wire will be used to ground the connection in the next step. (Top pin of this inter-PCB connector).


Note: The “’Danger 110V AC’ refers to the internally-generated low current bias supply for the LCD backlight, not a.c mains.

5)      Re-apply mains supply to the Symphony and ensure that safe workshop practices are employed.

6)      Ground the wire end by touching it to chassis. The LCD display should become visible to some extent.

7)      Use this temporary LCD visibility to adjust the contrast to a suitable level using the front panel controls. Remove the wire’s ground connection periodically to check your adjustments.

8)      Once LCD contrast has been corrected, the wire can be unsoldered remembering first to remove the mains supply.


Finally, consider activating the Symphony’s front panel ‘password’ function to prevent future adjustments by well-meaning fiddlers!

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