[wa2ise]

That 4KV ceramic cap is the sort normally used in the horizontal deflection circuitry. Doesn't seem likely to be used in the sound detector. As Chad points out, it's likely 100pF and thus would look to be open with your ohm meter. Does it look like original equipment, or a repair part? In either case, it might have been a case of a lack of regular 100pF caps either in production or the shop, and were used to get the TVs shipped or back to the customer. Sure, the 4KV part would be expensive, but holding up production would be more expensive yet.