SHARP VC-AH990A
Manual de Servicio

FLOW CHART NO.20 PLAYBACK MODE TROUBLESHOOTING Although picture playback is possible, colour does not appear in PAL or NTSC Playback picture does not appear (E-E mode is possible).

NO there FM signal (approx. 0.4Vp-p) input line between (79) and (78) Is voltage 5V applied to the chroma power Check peripheral circuit pins (61) of IC201

VC-AH975W VC-AH990A/W VC-AH770A/L/M/Ru

the (78) IC201. terminal at pin (61) of IC201? and Y/C 5V line.

YES

FM 0.4Vp-p) Is there chroma signal (approx. Check line between pins (60) and (46) of output from the pin (79) of IC201? 156mVp-p <PAL mode> or IC201 (C512).
NO NO YES

298mVp-p<NTSC mode> /burst) input in the pin (46) of IC201?
YES (81) IC201? Check whether the pins(73) and (75) of

Is the supply V-H.SW.P signal fed to pin For PAL/MESECAM mode.
NO

IC201 oscillate 4.43MHz. For NTSC mode. Is there chroma signal (approx. whether the pins(73) and (71) of Check V-H.SW.P line. 197mVp-p <PAL mode> or NO IC201 oscillate 3.58NHz. 375mVp-p<NTSC mode>/ burst) input to the pin (58) of IC201? Is there luminance signal (approx. 0.25Vp-p) NO

Check peripheral circuit of pins (13), (14) and (17) of IC201. For PAL/MESECAM mode.

NO input output in the pins (13), (14) and YES (17) of IC201?

Check parts arround of X501. Check parts arround of X502.

YES For NTSC mode.

Is there luminance signal (approx. 0.5Vp-p) NO Check line between pins (18) and (19) of inputted to pin (19) of IC201? IC201 (C206). Is there chroma signal (approx. 300mVp-p <PAL mode> or YES Check line between pins (58) and (35) of IC201 (R505, C515).
NO Check line between pins (21) and (42) of input to the pin (54) of IC201? Is there luminance signal (approx. 0.3Vp-p)

YES 286mVp-p<NTSC mode>/burst)

44
IC201 (C208). inputted to pin (42) of IC201? NO Is there chroma signal output from pin (55) 197mVp-p <PAL mode> or
YES

YES

YES

Is there chroma signal (approx.

Is there luminance signal (approx. 0.5Vp-p) NO Check line between pins (39) and (26) of IC201? 375mVp-p<NTSC mode>/ burst) inputted to (26) IC201 (C212). input in the pin (35) of IC201? Check line between pins (55) and (54) of IC201 (C514).
NO

NO YES

Is there luminance signal (approx. 0.5Vp-p) output from the pin (39) of IC201?

Replace IC201. Is voltage 5V applied to the CCD section power terminal at pin (36) of IC201?
NO

Is CCD control voltage approx. 5V normally to the (37) from pin (57) of IC201? Is clock signal (approx. 8.86MHz<PAL mode> or 7.16MHz<NTSC mode>/0.5Vp-p) for CCD applied normally to the pin (44) from (69) of IC201?
NO

Is there luminance signal (approx. 0.5Vp-p) inputted to pin (23) of IC201? Check line between pins (24) and (23) of IC201 (C210).

YES

Is there video signal (approx. 2.0Vp-p) outputted to pin (52) of IC201?

NO

Replace IC201.