Hickok 539C - Switch and Sensitivity Adjustments; Shorts Test Switch Contact Check; Shorts Light Sensitivity Adjustment; Leakage Resistance Meter Test Setup

4.1 Adjustment
No adjustment. Failure to read a short on any switch position means the switch contacts are dirty or damaged.
Clean ing and de-ta rn ishing the contacts may help.
5 SHORTS LIGHT SENSITIVITY
Set the CATHODE SWITCH to position 8 and the PLATE switch to position 3. Connect a 300K, 1/2W, 5% resistor
between pins 3 and 8
of the octal socket. Rotate the SHORTS switch counter clockwise to position 4. The SHORTS
lamp should be glowing or flickering dimly. Rotate the SHORTS switch to the TUBE TEST" position and discon nect
the 300K resistor.
5.1 Adjustment
If the lamp fails to light, replace the lamp and/or perform the test again and adjust R45 until the SHORTS light just
comes on.
6 LEAKAGE RESISTANCE METER TEST
Connect a 1M, 1/2W, 5% resistor between pins 3 and 8 of the octal socket. Rotate the SHORTS switch clockwise to
position D. The main meter should be reading approximately 1M ohms on the resistance scale. Rotate the SHORTS
switch backto the TUBE TEST position and disconnect the 1M resistor.
6.1 Adjustment
No adjustment. Ifthe reading is wrong check resistors R46/ 1M, R47 /36Kand R48 /330K. Also checkthe main
meter movement sensitivity
as described in section 16 (MUTUAL CONDUCTANCE READING TEST) below.
Set up the tester for the remainder of the tests by setting the switches to the following positions (6L6):
NORMAL/SELF BIAS = NORMAL
VR VOL TS & MILS CONTROL = COUNTERCLOCKWISE
BIAS RANGE = 50V
BIAS VOL TSNR VOL TS & MILS (toggle switch) = BIAS VOL TS
BIAS VOLTS CONTlWL = COUNTERCLOCKWISE (Zero volts)
MEITR =NOR~L
SELECTORS:
FILAMENT
FILAMENT
GRID
PLATE
SHORT TEST
SHORTS
CATH.ACr
SHUNT
FILAMENT
=H
=S
=5
=3
PLA TEVOLTS
FUNCTION SWITCH
SCREEN =4
CATHODE =8
SUPPRESSOR = 1
= OTHER TUBES
= TUBE TEST
= NORMAL
=0
=6.3
=NOR~L
=C (15,000)
24