E8257D/67D, E8663D PSG Signal Generators Service Guide 111
Troubleshooting
Troubleshooting Unlevels
3. If the RF signal levels are good, most likely the problem is either a
detector, ALC, or modulator. Before proceeding, turn ALC On and set the
signal generator to maximum leveled power for the model and options you
have and note the frequencies where the unleveled condition occur. Later,
when troubleshooting in ALC Off mode the unleveled indication is turned
off.
4. For each of the failed conditions listed, always start with the following
signal generator settings:
— ALC Mode ALC Off
— Amplitude +30 dBm (max.)
— Attenuator Hold Mod On (if Option 1E1 is installed)
— RF On
— Modulation Off
Conditions:
5. Unleveled only between 250 kHz and 2 GHz. (Applies to all frequency
options)
If the unleveled problem only occurs between 250 kHz and 2 GHz, the
problem is most likely the
A23 Lowband Coupler/Detector.
a. Checking the A23 Lowband Coupler/Detector:
— Set the signal generator to 1.9 GHz or an unleveled signal
generator frequency.
— Connect a power meter or spectrum analyzer to the A23
Lowband Coupler/Detector output.
— Set the signal generator to 1 GHz. Using the RPG, adjust the
amplitude level so the detected voltage on cable J5 of A10
ALC (W14) is –0.117 Vdc. Using a power meter, measure the
signal level at the end of the cable going to J3 of A30
100 kHz to 3.2 GHz
w/UNX + 1EH
b
+12 +23 +15 +23
>3.2 GHz to 9 GHz +15 +23 +14 +22
a. Always check data sheet for updates to specifications
b. With Option 1EH Low-pass Filters below 2 GHz switched off. With fil-
ters on, this specification applies above 2 GHz.
Table 1-17 E8663D Maximum Leveled Power (dBm)
a
Frequency All Models
Std. 1EU 1E1 1E1+1EU
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