neazoi

My vectrex has no image displayed on the screen after replacing two chips in the logic board with the same type. The filament of the tube does not light up. I measured the filament for continuity and it is ok but no voltage on it. It worked before I replaced these chips. Is there any way that the logic board sends commands to light up the filament? I do not think so. Only 6,7 and 8 pins at the output transrofmer have 12v on them. These are in the primary. The secondaries have no voltage. Probably a blown HV transformer? However, I do not hear any sound when powering up the vectrex,shouldn’t I regardless of the screen working or not? Please help