Shruthi LCD Intermittent

I’ve just completed my first Shruthi 1 and it all works except the LCD sometimes becomes fainter or goes blank. The audio and general functionality is unnaffected. Is this a poor solder joint somewhere? Anyone suggest how I start problem solving it?

It’s very likely to be a weak solder joint on the LCD contrast trimmer.

Redone the trimmer connections and all seems to be working well. Thanks very much!