Technics RS-M215

RS-M215
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:
_ _ fi—fe
Tape speed fluctuation = 3,000 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
1.
Test
equipment
connection
is
shown
in
Playback
frequency
response
chart
fig. 4.
2. Place UNIT into playback mode.
3. Playback the frequency response test
tape (QZZCFM).
4. Measure output level at 315Hz, 12.5kHz,
8kHz, 4kHz, 1kHz, 250Hz, 125Hz and
63Hz, and compare each output level
with the standard frequency 315Hz, at
LINE OUT.
5. Make measurement for both channels.
6. Make sure that the measured value is
within the range specitied in the frequency response chart (shown in fig. 10).
Fig. 10
@ Playback gain
Condition:
* Playback mode
* Tape selector
-+-Normal position
Equipment :
*VTVM_ * Oscilloscope
« Test tape ---QZZCFM
@ Erase current
Condition:
* Record mode
* Tape selector
--»Metal position
Equipment:
*VTVM * Oscilloscope
© Overall frequency
response
Condition:
* Record/playback mode
* Tape selector
«+ Normal position
«++ CrO2 position
-+- Metal position
* Input level controls --- MAX
1. Test equipment connection is shown in fig. 4.
2. Playback standard recording level portion on test tape (QZZCFM 315Hz), and using VTVM measure
the output level at LINE OUT.
3. Make measurement for both channels.
Standard value: 0.4V+1dB [around 0.42V: at test points TP5 (L-CH) and
TP6 (R-CH)]
Adjustment
1. If measured value is not within standard, adjust VR1 (L-CH), VR2 (R-CH) (See fig. 2 on page 3).
2. After adjustment, check “Playback frequency response” again.
1. Test equipment connection is shown in fig. 11.
2. Press the record and pause buttons.
3. Set the tape selector to metal position.
4. Read voltage on VTVM and calculate erase current by
following formula:
Erase head
‘2 Voltage across both ends of R101
1(Q) TP4
Standard value: 160139 ma (Metal position)
5. lf measured value is not within standard, adjust as follows.
Erase current (A
VTVM Oscilloscope
Fig. 11
Adjustment
1. Open the point (A) and short the point (B) on the main circuit board in the wiring connection diagram
(See page 8).
2. Make measurement for erase current.
3. Make sure that the measured value is within the erase current of 140mA to 170mA.
4. If it is beyond the value, carry out the following adjustments:
* If the erase current is less than 140 mA, short the point (A).
* If the erase current is more than 170mA, open the points (A) and (B).
Note 1: Overall frequency response chart (Normal)
Before measuring and adjusting, make sure of
the playback frequency response (For the
method of measurement, please refer to the
——-
Okt
Hz 4kHz 8kHz
+ +
1dBE~__10OH2z 200H2 — 500H2 "kHz AkHz BkHz B
playback frequency response). fe a at a Me “aye
Note 2: —AdBp---77 = tbt8
Test tape QZZCRA to be supplied after July —708
1980 has higher recording sensitivity in the
middle and high frequency range.