HP 8508A - Page 82

Adjustments
5.9 IF ASSEMBLY ADJUSTMENTS
_ Set up the centre frequency of the Channel A and B Bandpass filters.
DESCRIPTION
The 20 kHz centre frequency for Channel A and B is 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, Adjust the cores of A3L1 and A3L2 to the top of the coils.
5. Select [PRESET] [SHIFT] [POWER MEAS] to put the instrument into the ‘ =e mode. The Displays will now
indicate which setup code is being used. This will appear as:
tSt nnnn
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 °2’ in Display 2. ,
Press [HOLD VALUE] and check that the indicator LED is ON.
6. Adjust the A3L1 core to obtain a maximum reading in Display 2.
7. Press [HOLD VALUE] to cancel the function.
8. Use the UP/DOWN "Arrow keys to set up test code ’3’ in Display 2.
Press [HOLD VALUE] and check that the indicator LED is ON.
9. Adjust the core of A3L2 to obtain a maximum reading on Display 2.
10. Press [HOLD VALUE] to cancel the function.
11. Replace the HP 8508A top cover.
54 : E1089
B
i
=
e
a
2
7
ry
ez
Hi
.
=
a
B
|_|
a
.