Removing The Cover; Reinstalling The Cover; Pm9624 (Hf Input); Pm9626B Gpib Interface - Fluke PM6685 Service Manual

The terms in the following figure are used in all descriptions in this
manual.
Left
Front Bottom
Fig. 3-1
Designations used in this manual.
The PM6685 is available with a number of options and accessories.
The labels on the rear panel of the counter identify the options and
accessories included. If there are no labels, the counter contains an
uncompensated crystal oscillator and no options. The following la-
bels exist:
–
PM9624 3.0 GHz HF input
–
PM9691 High-Stability Oven Oscillator
– PM9692 Ultra-High-Stability Oven Oscillator
–

PM9626B GPIB Interface

The location of these optional parts is illustrated in Fig.3-2.
Power
Module
Main board
Front panel
Fig. 3-2
Location of the boards in the counter.
3-2 Disassembly, Removing the Cover
Top
Rear
Right
GPIB interface
Optional
oscillator
G 1
HF input

Removing the Cover

WARNING: Do not perform any internal service or ad-
justment of this instrument unless you are qualified
to do so.
WARNING: When you remove the cover you will ex-
pose high voltage parts and accessible terminals
which can cause death.
WARNING: Although the power switch is in the off
position, line voltage is present on the printed cir -
cuit board. Use extreme caution.
WARNING: Capacitors inside the instrument can hold
their charge even if the instrument has been sepa -
rated from all voltage sources.
–
Make sure the power cord is disconnected from the counter.
–
Turn the counter upside down.
– Loosen the two screws (A) at the bottom and the two screws
(B) in the rear feet.
–
Grip the front panel and gently push at the rear.
–
Pull the counter out of the cover.
A
Fig. 3-3
Remove the screws and push the counter out of
the cover.

Reinstalling the Cover

–
Gently push the counter back into the cover.
–
Turn it upside down.
–
Install the two screws (A) at the bottom.
–
Install the two rear feet with the screws (B) to the rear panel.

PM9624 (HF Input)

–
Disconnect the power cable.
–
Remove the cover from the counter.
– Disconnect the cable from the mini-coax connector (A) on the
HF input.
–
Press the clips (B) apart and lift the HF input pca straight up
and out.
A
B
B