The interesting thing about accutron watches is that they won't run until you replace the case back. You won't hear the typical tick tick of a standard watch but rather a humming sound comming from the tuning fork. Try putting the chase back on and screwing it down and then look at the sweep seconds hand to see if it is moving. If it isn't, listen for the humming of the watch. If you hear that then you will need to take it to a Bulova accutron trained watch maker for service. What ever you do, do not take it to a normal watch shop because it takes special training to repair one of these watches.
It is well worth spending the money to have it repaired if that is what it needs because it is a piece of your family history and should be passed down to the next generation family member along with some of the history of your grandfather. PRICELESS.
It is a lovely watch and something to be proud of.
In reply to I'm with bobbee, 1. Make by FifthAvenueRes…
You have a very unusual cased Accuquartz watch. I have the exact same watch. The case takes a special steel insert into which the movement is set. There is an o-ring gasket under the steel insert as well as a flat gasket under the case back. It really isn't necessary to close up the watch to make it run after installing a new battery but it is good to at least snug up the back so the movement is covered and protected. If the watch has not run in many years, the lube oil may be stiff. A slight, gentle tap of the side of the case at the 9 o'clock position to a counter top may persuade the tuning fork to vibrate. BTW, the stepped side of the battery must face up in an Accutron, unlike other battery operated watches. If the fork does not starrt to hum after a few taps, it will most likely need service. The Accuquartz movement is different from all other Accutron movements and most watchmakers who work on Accutrons won't work on the Accuquartz. I use a watchmaker in Bulgaria who has all parts and equipment to service tha movement. Again, that case is rare for an Accutron. It is large and heavy as are more modern watches. Gold plating of 20 microns is reasonably thick but not the thickest used. Let me know if you have other questions.