Actually I did that a while back, it measured 8.45 volts without the bulb in place, so it is an 8 Volt bulb. These are not too common, but the original bulb manufacturer apparently doesn't make then any more; a second source makes 6 Volt and 12 Volt versions, or at least those are the ones stocked at Mouser, who doesn't carry the 8 Volt version if still available. I did manage to get an 8 Volt fuse bulb out of a Sony AM/FM Stereo Receiver that had gone bad, and about a week later ordered a couple of dozen 8 Volt fuse bulbs on the net as backup. I also managed to finally find the KW-8077 Service Manual in Germany, and ordered it.