19 Mar 2021, 01:43
Short answer to your question...no. It's just a variable (cadmium-sulphide) resistor that regulates the width of the pulses enabling the digits (part of the multiplexer circuit), in order to vary the display brightness in changing light conditions. If it's missing, the circuit reads that as low light level, and dims, but does NOT extinguish, the display. So, if your module is not showing any display, the primary problem lies elsewhere.
I guess, if you got the watch cheaply enough, you won't get hurt too badly on this, but, chances are you're going to need a new module. NEVER buy a non-working watch on the assumption that it will be a simple fix...in twenty years, I've managed to do that exactly five times (and, mostly in just the last few years, when I knew much more about what I was looking at). Sometimes, working condition is not a significant factor (like the 18K Tiffany Calculator that just sold for marginally over the "melt" value), but usually, unless it's obviously working, the value just isn't there. I would hate to miss a genuinely good deal because I had expended my resources on bargain-hunts.