Sharp DV-NC70U Service Manual - Page 43

DV-NC70U/C DV-NC72U 43 FLOW CHART NO.13 The capstan motor fails to run. NO Is the voltage more than about 2.6V DC given out of pin(29) of IC701? YES NO Is the supply voltage of 5V fed up to pin(3) of AC connector? YES Is the voltage more than 2.6V DC sent in pin(9) of NO AC connector? YES Is approx. 3.5V applied to the pin(5) of NO AC connector? YES Is 29V applied to the pin(2) of AC connector NO normally? YES Replace capstan motor. FLOW CHART NO.14 The drum motor fails to run. Is the voltage more than about 2.6V DC given out NO of pin(30) of IC701? YES NO Is the supply voltage of 5V fed up to pin(3) of AC connector? YES Is the voltage more than about 2.6V applied at NO pin(12) of AC connector? YES Is the supply voltage of 12V fed up to pin(8) of NO AC connector? YES Check or replace drum motor. FLOW CHART NO.15 The drum motor runs only for a few seconds. Is drum PG/FG signal given out of pin(11) of NO AC connector? YES Is drum PG/FG signal given out of pin(65) of NO IC701? YES Is V-H.SW.P pulse given out of pin(23) of IC701? NO Replace IC701. YES Check IC701. Check PC 5V line. Check between the pin(9) of AC connector and all the way up thru to pin(29) of IC701. Check the pin(91) of IC701. Check AT 27V line. Check IC701. Check PC 5V line. Check between pin(30) of IC701 and all the way up to pin(12) of AC connector. Check PC 12V line. Check or replace capstan motor or drum motor. Check line between pin(11) of AC connector and all the way up thru to pin(65) of IC701. Check IC701. FLOW CHART NO.16ɹɹɹɹɹ No head switching pulse. NO Is the drum motor rotating? YES Is the drum PG signal and drum FG signal present on pin(65) of IC701, respectively? YES NO D-FG See FLOW CHART NO.14, 15. Replace IC701. D-PG Are the drum PG/FG signals present on pin(11) of NO AC connector? YES Check or replace capstan motor unit and drum motor unit. About 5Vp-p About 5Vp-p Check line between pin(11) of AC connector and all the way up thru to pin(65) of IC701. FLOW CHART NO.17 Drum servo does not function. Is there 14.3MHz oscillation at pins(37) and (38) of IC701? YES In PB mode Is there drum PG/FG signal at pin(65) of IC701 present? YES NO Is the head switching pulse at pin(23) of IC701 present? YES Is the drum APC output at pin(34) of IC701 and drum AFC output at pin(32) of IC701 present? YES Is the drum control voltage applied to pin(12) of AC connector? YES Replace capstan motor or drum motor. NO Check peripheral circuit of X701. In REC mode YES Is there V-SYNC signal (reference) at pin(50) of IC701? NO Check peripheral circuit of C715, C716 and R708. Check drum PG/FG signal line. NO See FLOW CHART NO.16. NO Replace IC701. NO Is pin(30) of IC701 in high impedance?