Vertical Sync Unstable - NEC DPro2070SB Service Manual

3.2.3.2 Vertical Sync Unstable

Check the vertical sync signal.
NG
OK
Check the vertical sync. or Vsync-out at Pin 32 of IC102.
NG
OK
Expected failure point
The vertical oscillation circuit is failure. (See Item 3.4.3)
Check the (V-SYNC) waveform at Pin 33 of IC102 on the
MAIN PWB. (Approx. 5Vp-p)
Check the vertical sync signal.
OK
IC102 on MAIN PWB or peripheral circuits
NG
Check the vertical sync signal.
OK
NG
Expected failure point
Signal cable, IC216 or peripheral circuits
Signal cable, IC102, IC105 or peripheral circuits
Check the (V-SYNC) waveform at Pin 5 of CN103
on the MAIN PWB (Approx. 5Vp-p).
Expected failure point
Check the (V-SYNC) waveform at Pin 15 of CN212 on the VIDEO
PWB. (Approx. 5Vp-p)
Expected failure point
CN103 or FFC cable
Expected failure point
3-6
Vertical
period
Vertical
period