I have a Heath Digital Floor Clock, model #GC-1195. Over the years, 25 of the 26 lightbulbs burnt out. The bulbs (#412-621) were 12 volt. All of my local part distributers say that those lightbulbs have not been made for years. Does anyone know where I might obtain some? Is it possible to use 13.8 volt lightbulbs in their place? Thanks in advance. Timeless, Mark