HP 8508A - Page 88

Adjustments
s
5-10 SEARCH & LOCK ASSEMBLY ADJUSTMENTS
Set up the centre frequency of the 1.62 MHz and 32.4MHz Oscillators.
DESCRIPTION
The centre frequencies are set up using an internal test routine.
EQUIPMENT
No external test equipment is required for this adjustment.
PROCEDURE
1, Remove the Input Module from the instrument.
2. Switch on the equipment and allow to warm up for 30 minutes.
Note:
Since
the
Input
Module
is
not
installed
in
the
mainframe,
the
HP
8508A
will
display
the
error
message “Err 601”. This reading should be ignored.
3. Remove the HP 8508A top cover to allow access to the adjustments.
4, Select [PRESET] [SHIFT] [POWER MEAS} to put the instrument into the ‘setup’ mode
The Display will now indicate which setup code is being used. It will appear as:
tSt nonn
tSt indicates that the instrument is in the ‘setup’ mode and ‘nnnn’ is the current setup code.
Use the UP/DOWN ‘Arrow’ keys to set up test code ’0’ in Display 2.
Press [HOLD VALUE} and check that the indicator LED is ON. _
5. Adjust A4R89 slowly until the UNLOCK light extinguishes.
Note:
The
green
LED
(CR6),
across
the
board
from
A4R839,
is
functionally
the
same
as
the
UNLOCK
light
on the front panel.
_ 6, Press [HOLD VALUE] to cancel the function.
7. Use the UP/DOWN ’Arrow’ keys to set up test code °2’ in Display 2.
Press [HOLD VALUE] and check that the indicator LED is ON.
8. Adjust the core of A4L3 slowly until the UNLOCK light extinguishes.
9. Press [HOLD VALUE] to cancel the function.
10. Replace the HP 8508A top cover.
5-12
E1089