Rohde & Schwarz R&S SMU200A, Service Manual

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R&S SMU200A Troubleshooting
1007.9845.82 3.27 E-6
Level Errors
Error Error correction
Output unlevelled at frequencies up
to 3 GHz, I/Q modulation on:
The following, more precise error
descriptions may appear:
gain control on upper limit
gain control on lower limit
gain out of setting range
Switch over to CW mode.
Error message “Output unlevelled” disappears:
Continue troubleshooting on LCM module
(see “
Tests on Submodule IOQOP3 LCM ”).
Error message “Output unlevelled” does not disappear:
Check for correct input signal to IQOP3 from SSYN at
connectors X272 and X273 (see “
Troubleshooting -
Module IQOP3 ”).
With incorrect input signals check cabling and continue
troubleshooting at module SSYN.
Error message “Output unleveled” does not disappear with
correct input : IQOP3/RFM is defective.
Frequencies > 3 GHz, I/Q modulation
on
Check for correct input signal at IQOP6, X284.
Level too low: check cabling and module IQOP3.
Level correct: continue troubleshooting at module IQOP6.
Frequencies > 3 GHz, I/Q modulation
off
The module IQOP3 is not involved here and can be ruled out as
the cause of error. Check module IQOP6.
No output level for CW Check output level of module SSYN, X244.
Output level incorrect: Check SSYN
Check level control using Hardware Debug Page
Select “level” .
Check control lines in “LCM (DSP Status, OK)” block
with RF ON
Pulse = 0
Blank = 0
Levatt0 = Levatt1 = 0
RF_DOWN = 0
If one of bits is incorrect: check control lines on
motherboard.
Measure control voltage of gain control element using Test
Point:
Freq < 3 GHz:
DIAG_IQOP3_LCM_LEVEL_CNTRL > 7.2 V ->
IQOP3/RFM is defective.
Freq > 3 GHz:
DIAG_IQOP3_LCM_LCON6 > 7.5 V -> IQOP6 is defective.