Just to clarify the bulb does 2 things
1) limit the current to HOT to protect it. If something
is drawing to much the bulb drops the voltage to the HOT.
If you do it with a shorted HOT or damper the bulb will have
all the 125 V across it & it lights normal but fuses wont blow.
2) trouble shooting aid. Some sets like GE used one of the
white caps instead of five. If it opened the HOT will blow in
milliseconds. Other things also could. you usually WILL NOT
find the bad cap with simple test equipt. The bulb trick allows
you to "unload" one thing from the FBT at a time till you
get a dim bulb with some HV.
73 Zeno
