1-10
Initial Troubleshooting and Overall Block Diagram
Initial Troubleshooting
Step 5: Measure the Individual Voltage Supplies
The voltages supplied as inputs from the power supply via J6 to the motherboard are +15V (TP502), +15V
standby (+15_STBY),
15 V (TP503), +12V (TP505), and +5.2V (TP302). DGND (TP301) is associated
with these supplies.
The
6V (TP508) and 5.2 (TP509) supplies receive their input from the +5.2V digital supply (5.2VD -
TP506). The +5.2V digital line is filtered to prevent the switching power supply noise from being induced
onto the
+5.2VD supply lines. The
6V is a bias voltage for circuits on the output board and other RF
circuitry.The
5.2V is used by the emitter coupled logic (ECL) digital ICs. The LCD display driver voltage
(VLCD), a
14V to 24V source, also receives input from the +5.2VD supply.
The input to the +32V supply (TP504) is the +12V supply. The +32V supply is used by the synthesizer/
doubl
er assembly. This supply also includes an LC noise filter.
The +12.5V regulated supply (TP510) originates from the +15V input. The
12.5V regulated supply
(TP511) originates from the
15V input. These two supplies are used by the solid-state attenuator and the
reverse power protection (RPP). The +10V reference (TP501) originates from the +15V input. The +9V
supply (TP507) originates from the +10V reference and the +12V supply.
1. Unplug the signal generator and turn it upside-down.
2. Expose the motherboard by removing the bottom cover. It is secured by 15 screws.
3. Plug in the signal generator.
4. Measure the voltage of each supply to verify the
y are within the tolerances listed in Table 1-2. The voltage supply
test point locations are shown in Figure 1-4. If all the voltages are within tolerance,
proceed to Step 7: Check for
Basic CPU Functionality.
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