TroubleshootingProcedures
WFM90D and WFM91D ServiceManual 6-53
Arethe
sync
pulses
OK?
Replacethe Top board.
Checkfor vert ical and horizontal sync pulses:
(J9is on Top Board.)
J9-18= TTL level V-rate sync lockedto the input signal.
J9-19= TTL level H -rate sync locked to the input signal.
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
Usethis proc edure when
theWaveform display
modesweep is not
triggered.
Checkthe R EF IN signal:
(J14is on Bottom Board)
J14-9= 1.2 Vpp, +1.3 VD C
blankinglevel.
Isthe REF
INsignal
OK?
Yes
Replacethe Bott om board.
No Replacethe
Inputboard.
Figure6 -28: Flowchart for untriggered waveform display