Replacing The Oven Triac - Agilent Technologies 7820A Service Manual

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Agilent 7820 GC Service
towards the front of the GC until it releases from the switch on
the board.
Rotate the mounting thumbscrew counterclockwise until an
audible "click" sound is heard. Then slide the board slightly
towards the center of the GC and lift it off its standoffs.
In reassembly, pay attention to the following:

Do not forget to reconnect the power switch push rod.

Make sure the new board is located on its standoffs.
Then slide it slightly away from the center of the GC such
that the mounting thumbscrew is properly positioned.

Engage the thumbscrew threads by pressing it
downwards gently while rotating clockwise.

Transfer the jumper wires from the old AC board to the
new one. For details on how to configure AC board power
using the jumper wires, see Converting the power
option ( 258).

Replacing the oven triac

1 Cool down the oven.
Turn off the GC main power switch and disconnect its power
cord.
Hazardous voltages are present in the
mainframe when the GC power cord is connected.
Avoid a potentially dangerous shock hazard by
disconnecting the power cord before removing
any GC panels.
Components can be damaged by static electricity:
be sure to wear an ESD strap grounded to the GC
chassis while performing this procedure.
Remove the AC board. See Replacing the analog and power
board ( 220).