Technics RS-TR474 Service Manual page 24

PLAYBACK FREQUENCY RESPONSE (DECK 1/2)
1. Playback the frequency response portion (315Hz, 12.5kHz~
63Hz, —20dB) of the test tape (QZZCFM).
2. Assure that the frequency response is within the range
shown in Fig. 4 for both L-CH and R-CH.
LINE OUT
ERASE CURRENT ADJUSTMENT
1.
With no tape loaded in the deck, press the Record button.
2. Check if the output at this time between the erase current
confirmation point TP1 and GND (chassis) is within the
standard value.
The voitage will vary
depending on the
ground Srovided.
CONFIRMATION OF THE OVERALL GAIN AND OVERALL Normal Overall frequency response chart (NR OUT)
FREQUENCY RESPONSE
1.
In the Record Pause mode, load a normal biank tape (QZZCRV)
into the deck, and apply the reference input signal (1kHz,
—24dB) to the Rec. input. Adjust the output to 320mV with
the attenuator, and start recording.
. While playing back the reference signal just recorded, verify
that the output level falls in the following range.
SOHz 100Hz 200Hz SOOHz kHz 2kHz
CrO, Meta! Overall frequency response chart (NR OUT)
. Afterwared, apply a signal (frequency at the measured point in
the range from 50 Hz to 10kHz), whose level is 20dB lower than PT TT
the reference signal level (1kHz, —24dB=approx. 63mV), to ee Sian
the Rec. input. Then start recording with a normal blank tape nt TT oth 1a
(QZZCRA).
Ni
|
i : Tia mnie
levels at the test frequencies fall in the ranges specified in CH
Fig. 5 with respect to the reference signal level. oe a
. Repeat steps 3 and 4 above for CrO, blank test tape (QZZCRX1) SOHz 100H2 200Hz SOOHZ 1kHz 2kHz 12.5kH2
and Metal blank test tape (QZZCRZ5), in these cases raising Fig. 6
the upper end of the test signal frequency range to 12.5kHz.
Verify that the signal levels at the test frequencies fall in the " LINE IN LINE OUT
ranges specified in Fig. 6 with respect to the reference signal
level. '
Steps 1 through 2 above are concerned with overall gain; —agosemator ATT "EVM. Oscilloscope
steps 3 through 5 pertain to overall frequency response.
. If outside the standard value, data in EEPROM should be written again by taking the following procedure and there
therafter section 1-5 should be carried out again.
(1) (2) (3) (4)
Step 1 on page 19 Step 5 on page 20 Step 9 on page 21 Step 10 on page 21