HP 416A - Maintenance

Maintenance
Cabinet Removal - -
1.
At the back of the i nstrument , remove the four screws which fasten
the rear cover to the chassis. Remove the rear cover.
2 . Turn the instrument on its back . Remove the two large Allen set -
screws on the bot tom, next to the control paneL Lift the cabinet off the instru -
ment .
Replacement
Tubes - Any tube in the Model 416A may be replaced with a tube having
corresponding RETMA standard characteristics. Whenever a tube is replaced,
the following table should be consulted to determine whether or not the charac -
teristics of the replacement tube will ne c essitate circuit adjustments. The
procedure for performin g such adjustments will be found below in the Adjust -
ment section.
Tube
Vl
V2A :
V2A/B
V2B :
V3
V4
V5
V6
V7A :
V7A/B
V7B :
Function
Input Amplifier, Incident/Refer enc~
Channel,
Constant Voltage Control Tube , Incid-
ent / Reference ChanneL
Constant Current Control Tube, Re -
fleeted/Probe Channel.
Input Amplifier , Reflected/Probe
Channel,
Intermediate Input Amplifier , Re -
fle ct ed / Probe Channel.
Variable Ga i n Tube , Del aye d AVC ,
In ci dent/Referen ce ChanneL
Amp l ifier , Delayed AVC , Incident /
Referen ce Channel.
Cathode Follower , Delayed AVC ,
Incident/Reference Channel.
Cathode Follower, Multi ar Amplitude
Comparator , I n ci dent/Re f erence
Channel.
Required Circuit Adj.
Not critical
Not critic al
Not critical
Not critical
Not critical
Not critic al
Not critical