Functional Errors; Osm Failure - NEC DPro2070SB Service Manual

3.3 Functional Errors

3.3.1 OSM Failure

Note: See "3.2 Abnormal picture" if a screen is not available even though a video signal input is entered.
Check the OSM signal output.
OK
NG
Check the horizontal sync input of IC212.
NG
R2D5 on the VIDEO PWB, or AFC line
OK
Check the vertical sync input of IC212.
NG
OK
Check the OSM control line (I
OK
NG
Check the user control IC on the MAIN PWB.
OK
NG
SW101-SW107 on the MAIN PWB, R10A-R10G, R10K or R10L
Measure the waveform at Pins 16-19 of IC212 on the VIDEO PWB while the
SELECT button is pressed. (Approx. 5Vp-p)
Expected failure point
IC211, R2D0-R2D2 or R2F6 on the VIDEO PWB
Measure the waveform at Pin 5 of IC212 on
the VIDEO PWB. (Approx. 5Vp-p)
Expected failure point
Measure the waveform at Pin 14 of IC212 on
the VIDEO PWB. (Approx. 5Vp-p)
Expected failure point
IC6A1 or Pin 32 of IC102
Measure the waveform at Pin 7 and 8 of IC212 on
2
C).
the VIDEO PWB. (Approx. 5Vp-p)
Expected failure point
IC212 on the VIDEO PWB
Expected failure point
IC102 on the MAIN PWB
Expected failure point
Measure the voltage at Pins 22 and 23 of user control IC102 on the MAIN PWB.
3-14
Horizontal period
Horizontal period
Pins 17,18, 19
Pin 16
Horizontal period
Vertical period