Technics RS-M13 - Page 8

RS-M13
ITEM MEASUREMENT & ADJUSTMENT
Tape speed fluctuation
Make measurements in same manner as above (beginning, middle and end of tape), and determine the
difference between maximum and minimum values and calculate as follows:
Tape speed fluctuation = ee x 100 (%) f:—=maximum value, f2 = minimum value
Standard value: Less than 1%
Note:
Please use non metal type screwdriver when you adjust tape speed accuracy on this unit.
® Playback frequency
response
Condition
* Playback mode
* Tape selector
---Normal position
Equipment
*VTVM — * Oscilloscope
* Test tape» QZZCFM
@ Playback gain
Condition:
* Playback mode
* Tape selector
--» Normal position
Equipment
*VTVM — * Oscilloscope
* Test tape--- QZZCFM
@ Bias leakage
Condition
* Record mode
* Input level controls --- MAX
* Tape selector
-+-Metal position
Equipment
*VTVM
* Oscilloscope
j——
Playback frequency response chart
12.5 kHz
1. Test equipment connection is shown in
fig. 24
2. Place UNIT into playback mode
3. Playback the frequency response test
ape (QZZCFM)
4kHz
63Hz 125 Hz
200Hz — S00Hz | kHz
+4dB
4. Measure output level at 315Hz,12.5kHz, +248 i a oad ae aT +248
8kHz, 4kHz, 1kHz, 250Hz, 125Hz and 0dB F}-~——~-~}€~---~- ------------ — 988
63 Hz. and compare each output level 208
with the standard frequency 315Hz. at
LINE OUT
ake measurement for both channels.
ake sure that the measured value is
within the range specified in the frequency response chart (Shown in fig. 28).
500 Hz
Fig. 28
1kH
63Hz 125 Hz 200Hz : kHz
12.5kHz
oo
ran
Test equipment connection is shown in fig. 24
2. Playback standard recording level portion on test tape (QZZCFM 315Hz, OdB), and using VTVM
measure the output level at LINE OUT
3. Make measurement for both channels
Standard value: around 0.39V |
Adjustment
1. If measured value is not within standard, adjust VR1(L-CH), VR2 (R-CH) (See fig. 22 on page 5).
2. After adjustment. check “Playback frequency response” again
L1(L-CH)
L2 (R-CH)
Record/playback
TPS(L-CH)
TP6(R-CH)
=
Record mode
1. Test equipment connection is shown in fig. 29
Place UNIT into record mode.
3. Adjust trap coil L.1 (L-CH), L2 (R-CH) so that measured
value on VT VM becomes minimum
4. Take adjustment for both channels
© Erase current
Condition
* Record mode
* Tape selector
--» Metal position
Equipment
* VTVM
* Oscilloscope
Test equipment connection is shown in fig. 30.
Press the record and pause buttons
Set the tape selector to metal position.
Read voltage on VTVM and calculate erase current by
following formula
BWNHH
Record mode Use
Voltage across both ends of R301
1 (Q)
Erase current (A) = ee ee
VTVM Oscilloscope
Fig. 30
Standard value: 155+15mA (Metal position) |
5. If measured value is not within standard, adjust as follows.
Adjustment
1. Open the point (A) and short the point (B) on the main circuit board in the wiring connection diagram
(See page 10).