TroubleshootingProcedures
6-54 WFM90D and WFM91D Service Manual
Usethis proc edure when
theVector display is
unlocked.
Removethe D isplay module. (For instruments with serial
numbersbelow BO20100, rem ove the Display module and
Backlightboard.) C onnect the AC Adapter and power up the
instrument. Select INT REF using the CONFIGURE menu.
No
Yes
Isthe
Waveformdisplay
triggered?
Checkthe Subc arrier Regenerator Oscillator
(SRO)control volt age:
(J9is on the Top board)
J9-12= approximately 1VDC
Isthe SRO
controlsignal
aDC
voltage?
No
Thisproblem can be c aused by either the Topor Bott om
boards,and can only be det ermined by replacing these
boardsone at a time.
Replacethe Top board.
Goto Figure 6--28.
Checkthe IF sc signal:
(J9is on the Top board)
J9-43= 300 mV filtered
squarewave.
No
Yes
Yes
Replacethe Bott om board.
Isthe
IFscs ignal
OK?
Figure6 -29: Flowchart for unlocked vector display