Anritsu 682XXB - Manual (Page 218)

5-52 682XXB/683XXB MM
TROUBLESHOOTING
TROUBLESHOOTING TABLES
Error 147 Internal FM circuitry failed
Description: Indicates a failure of the internal frequency modulation
function. The 682XXB/683XXB may or may not provide frequency
modulation of the RF output signal using modulating signals from an
external source.
Step 1. Set up the 682XXB/683XXB as follows:
a. Press SYSTEM , then Reset .
b. Press MODULATION , then FM to go to the Internal FM
Status display.
c. Press On/Off to turn internal frequency modulation on.
Step 2. Using an oscilloscope, verify the presence of a 10 volt peak to
peak sine wave signal with a period of 100
ms at the rear
panel FM OUT connector.
G If present, replace the A11 PCB.
G If not present, replace the A8 PCB.
Table 5-26. Error Message 147
Error 148 Pulse 40 MHz reference circuitry failed.
Description: Indicates a failure of the pulse generator 40 MHz oscilla-
tor circuitry. The pulse generator may still function; however, the
40 MHz oscillator is not phase locked to the 10 MHz reference time-
base. The pulse modulation function may or may not operate. Error 106
(Power Supply not Phase-locked) may also be displayed.
Step 1. Disconnect cable W108 at A6J1.
Step 2. Using an oscilloscope, verify the presence of a 10 MHz at the
end of cable W108.
G If present, replace the A6 PCB.
G If not present, go to step 3.
Step 3. Reconnect cable W108 to A6J1 and disconnect it at A5J4.
Step 4. Using the oscilloscope, verify the presence of a 10 MHz TTL
signal at A5J4.
G If present, replace the cable W108.
G If not present, go to step 5.
Table 5-27. Error Message 148 (1 of 2)