I thank Owner-Manuals.com for providing the necessary manual very quickly, and it was very helpful in repairing my personal Audio System and I once again thank them for the wonderful customer's service satisfaction.
Thanks.
Very usefully, I could find the trouble clearly with that manual.
Text excerpt from page 66 (click to view)
10-9. VCR VIDEO CIRCUIT
A. TROUBLE SHOOTING OF PREAMP IN THE PLAYBACK MODE.
IY04 : LA70001
IS THE SIGNAL FROM HEADS FED TO PIN1 AND PIN3 (LP MODE) OR PIN 5 AND PIN 7 (SP MODE) OF PAY01. OK IS ON/OFF 5V FROM PIN 76 OF IY01 SUPPLIED TO PIN 13 OF IY04 AT 5VOLTS ? NG CHECK ON/OFF 5V NG CHECK DRUM AND DECK MECHANISM.
OK IS REC (H) FROM PIN 19 OF IY01 SUPPLIED TO PIN 11 OF IY04 AT ZERO VOLTS ? NG CHECK REC (H)
OK IS H.AMP SW FROM PIN 16 OF IN01 SUPPLIED TO PIN 3 OF IY04 ? NG CHECK H.AMP SW
OK IS VIDEO SW FROM PIN 18 OF IN01 SUPPLIED TO PIN 4 OF IY04 ? NG CHECK VIDEO SW
OK IS TRICK(H) FROM PIN 21 OF IY01 SUPPLIED TO DN07 AT ZERO VOLT ?� NG CHECK TRICK (H)
OK IS THE SIGNAL FROM PIN1 AND PIN3 (LP MODE) OR PIN5 AND PIN7 (SP MODE) OF PAY01 FED NG CHANGE IY04
OK IS THE SIGNAL FROM PIN7 OF IY04 FED TO C354 ? NG CHECK PB EQ
OK CHECK VIDEO CIRCUIT
REC(H) : "HIGH" IN THE RECORD MODE
H.A SW : "HIGH" IN THE LP MODE "LOW" IN THE SP MODE TRICK(H) : "HIGH" IN THE TRICK PLAY
