Rohde & Schwarz R&S SMU200A, Руководство по обслуживанию

Страница: 171 / 294

Troubleshooting R&S SMU200A
1007.9845.82 3.44 E-6
Error messages concerning the module IQOP6
Error message Error correction
Error messages concerning IQOP3/RFM and /LCM These errors have to be cured first,
because of interaction. Levelling circuitry
for IQOP6 is placed on IQOP3 and RF
signals are interchanged between the
modules.
All level related error messages, that appear only at
frequencies >3 GHz
•
Check proper connection of
signals LCON6 and UDET6.
•
Check ALC functionality
•
Check control lines on
motherboard.
Check ALC functionality Result and possible error cause
Signal Generator setting:
Frequency 5 GHz,
Level 0 dBm,
ALC State On
Attenuator Mode Fixed.
Disconnect cable connection LCON6 (W1285) and
UDET6 (W1286) .
Connect IQOP3/X265 to IQOP3/X266. Monitor
voltage on this connection using a T-piece or use
diagnostic system, Testpoint
DIAG_IQOP3_LCM_LCON6.
Now vary the level in 0.1 dB steps using spin
wheel.
•
The monitored voltage has to
vary smoothly between 0 and 2.5
V.
If there is no variation or only
rough steps, LCM does not work
properly and has to be serviced
or replaced first.
Check control lines on motherboard Result and possible error cause
Very low or no output level at f > 3 GHz:
Check the logic states of the control lines from the
motherboard (X281) (Low = 0 V, High = +3 V):
Press PRESET key
Set RF Frequency to 5.8 GHz
Set RF State to On
Check lines
X281.D9 PUM_N = High
X281.C8 LEVATT_20DB = Low
X281.A12 LEVATT_40DB = Low
X281.A8 RFDOWN2_N = High
Incorrect logic level:
Check source modules DAC
Interface and Universal Coder