Sanyo M9998LU Service Manual

Adjustment of record/playback frequency response(Bias adjustment)Feed input signal of 5 mV (—46 dB) 1 kHz into the lineinput terminal. Turn the input control knob until theoutput at measuring test points (see above) becomes 40mV. Under this condition, turn SVR701 and SVR702 untilthe difference between record output playback outputbecomes 0 whether the signal is 1 kHz or 10 kHz.NOTE:When adjusting, set the signal of line input at “OFF” state.ARO OGLWfi ATTENUATORa)) Ss4= ;giAdjustment of record and playback levelsFeed input signal of 50 mV (—26 dB) 1 kHz into the lineinput terminal. Turn the input control knob until theoutput at measuring test points (see above) becomes 0.58V. Record, Adjust SVR802 and SVR902 so that the recordinput becomes equal to the playback output.NOTE:When playing back, set the signal of line input at “OFF”state.|~ |~\\ i ATTENUATORJo cH) ad Hl-<oeolBBSQO-Adjustment of ALC balanceTurn on ALC switch.Feed input signal of 500 mV (—6 dB) into the tine inputterminal. Set in record mode. Adjust by turning SVR703until levels at measuring test points become uniform.Adjustment of tuning meterFeed input signal of 98 MHz, 66 dB into the set. Tunein the reception frequency of the set. Adjust SVR301(10 kB) so that the meter swings up to graduation 9.5.(1) If the meter swing becomes larger as the input is beingincreased, adjust after raising the input until the meteris stabilized.(2) If the maximum point of meter swing does not coin-cide with the maximum output point, turn off AFCswitch (to short-circuit TP4 and shield case), and tunein to the maximum point of meter swing. In this set-ting, adjust T303 to obtain the maximum output. Atthis time, keep the input at 50 dB,Adjustment of FM MPX (multiplex)(1) Set SVR501 (10 kB) in the central position.(2) Apply modulation input into FM SG through stereomodulator. (* Modulation frequency is 400 Hz.)Pilot signal 7.5 kHz dev. (10% mod.)Stereo signal 22.5 kHz dev. with “‘main’’ signal(30% mod.}NOTE:Since the method of adjusting the modulation differsfrom one instrument to another, learn the method forthe instrument you are going to use.(3) Keeping thé output signal switch of stereo modulatorat MAIN (L + R), set the radio’s reception frequencyto 98 MHz, and tune in with FM SG. (* Output of FMSG is 66 dB.)(4) 19 kHz adjustment (V.C.O. adjustment)in FM stereo mode, connect frequency counter to TP6,and cut the output of stereo modulator to set in no-modulation state. Turn SVR501 (10 kB) to adjust to19 kHz + 50 Hz.* No-modulation state: Turn off PILOT and MAIN &SUB of output signal switch.Adjustment in no-input state is difficult because19 kHz signals fluctuate due to noise component,but it is possible to adjust in away that the averageof indications be 19 kHz + 50 Hz.