SMARTFADE 1248 channel faders unresponsive

We have a Smartfade 1248. Suddenly and without any noticeable reason the faders for all channels became unresponsive.

The Bump Buttons Work for each channel.

The faders work for all previously saved memory channels.

However, when switching from the memory channels to the individual channels (1 through 48), there is no response, not even on the LCD panel.

Can anyone help solve this mystery?

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