E8257D/67D, E8663D PSG Signal Generators Service Guide 135
Troubleshooting
Overall Description
Line Module
The line voltage connects to the power supply through the A22 Line Module.
Because the power supply automatically detects and adjusts to different line
voltages, manual line voltage selection is neither necessary nor available.
Power Supply Thermal Sensors and fans
Two thermal sensors prevent the signal generator from overheating. One
sensor is internal to the A19 Power Supply; the other sensor is on the A8
Output. If the signal generator goes into thermal shutdown, the amber and
green LEDs on the front panel blink on and off.
There are two fans in the instrument. One fan cools the power supply. The
other is a variable speed fan that increases and decreases its speed to regulate
the instrument’s internal temperature. For reliability, it is important to operate
the instrument with the covers installed to ensure proper airflow and cooling.
Input/Output Interface
Front Panel
The signal generator accepts inputs through the front panel hardkeys and the
display softkeys, and provides outputs on the front panel display, and through
the RF output connector. Depending on the model, features, and options, the
front panel may have modulation input/output BNC connectors installed but
not operational if the option associated with that connector is not also
installed.
When line voltage is present and the signal generator is in standby mode, the
amber LED above the power switch lights. When the signal generator is in
power–on mode, the green LED (also above the power switch) lights.
Hardkeys/Softkeys
The front panel has two types of keys:
Hardkeys are dedicated to specific functions, entering values for the most
commonly used features, and controlling the display’s contrast and intensity.
The front panel keypad uses a row and column configuration. Pressing a key
makes a connection between a row and column. The row and column
information is routed to the A18 CPU where it is interpreted, and the
corresponding function executed.
Softkeys, located along the display, are used to select the function displayed
to the left of the key (on the display). When a softkey is pressed, the displayed
function changes.
A2 Display
A liquid crystal display (LCD) provides information about the instrument's
settings and condition. The LCD requires a power supply, lighting, and data:
To Next Page
Loading...
Need help?
General
