======================VACUUM_TUBE======================

TOTAL                 THERMAL EiuissivITY  OF ELECTRON-TUBE MATEiiIALS.
       Temperature    Thermal
Material          K   Emissivity
Aluminum        450   0.1
Anode graphite 1000   0.9
Copper          300   0.07
Molybdenum     1300   0.13
Molybdenum     1300   0.5   quartz-blasted
Nickel          600   0.09
Tantalum       1400   0.18
Tungsten       2600   0.30

======================COMPONENTS_VACUUM_TUBE===========================

VACUUM_TUBE           DEFECTS TO LOOK FOR IN  ELECTRONICS
                      Thick accumulations of dust or grime.
                      Missing components or mechanical parts.
                      Burn marks on components Particularly resisto~.
                      Deposits of melted wax or oil indicating overheating 
                      Leakage from capacitors or batteries
                      Crumbling insulation on the line cord or chassis wiring.
                      Cold or broken solder joints.
                      Loose or damaged mechanical parts 
                      indicating the unit has been dropped
                      rust indicating storage inh high humidity or
                      Blown fuse or no fuse in a fuse holder...~it it had one.