[quote="vpn"]I've searched on the forum about a possible retrofit, seems that only MSA modules could be fitted, since the ESA ones have a small plastic "tooth" at 12 'o clock that allows them to not move inside the case. I hope the watch works, otherwise I'll have to search for a working MSA module, used by various brands (such as Nepro, Bulova and Candino).
MSA modules are recognizable by the layout of batteries: they have a "+ +" layout instead of the "- +" one seen in ESA modules, and they were available both with light (which required two LR41 batteries) or without (requiring only one). Here's a picture of the MSA module without light, fitted in a Nepro LCD (picture source Flickr):

I have the Nepro LCD watch that has the same module thats from Flickr here, the MSA module...does anyone know what year that watch came oput? My best research says 1977....