Hello golyo79,
The lamps you require are a type 73 1watt 14 volts, more than likely the substitute ones you used will have been the incorrect voltage or wattage.
Use of these may have effected your sound to light unit, I would check out that there is no dry joints (called cold joints in the USA) on the sound to light lanp connection sockets.
Regards
Alan Hood
ami-man
UK