Hitachi V-209 Service Manual

							Then 
connect  the battery  pack connector  to the 
connector  of the  oscilloscope. 
d)  Mount  the plate  with screws. 
e)  Fix the upper  enclosure  on the  oscilloscope  with 
four  screws. 
Fig.  a 
Fig.  b 
  Upper 
enclosure 
, 
Bauery 
Ba  ucry  pack 
Battery pack fi,ing  �crew 
AD-209 
When  mounting  the battery  pack AD-209,  take care not 
to  damage  the connecting  cables and components.  6. 
HOW 
TO PRODUCE  THE BRIGHT  LINE 
Before  turning  0 the  POWER  switch. insure the power 
supply  voltage  is within  the range  of 90-J30V  for AC  IOOV 
set.  180  260V  for AC  200V  set. 
Insert  the plug  of the  power  cord on the  rear  panel  into the 
power  supply  wall socket  and set the  controls  as follows. 
POWER  OFF 
IN  TEN  Counterclockwise 
to the  full 
FOCUS  M1drange 
AC-GND-DC  GND 
�I  POSITION 
Midrange {the knob  is left 
depressed  ) 
V.  MODE  (Ill 
TRIG  AUTO 
TRIG  SOURCE  CHI 
TIME/DIY  0.5 
ms/div 
:::  POSITION 
I Midrange 
Set  all the  levers  of the  switches  to the  upper  side. 
After  ending  all the  setting  mentioned  above. turn 0 the 
POWER  and. 15 second  later, rotate  the INTEN  knob clock­
wise.  Then the sweep  bright line will  appear.  If the  observation 
is  to  be  started  immediately.  set the  FOCUS  control at a point 
where  the bright  line is sharpest. 
17  
						

							If 
the  instrument  is not  used  with  the power  supply  turned 
on.  rotate  the I  TENsity  counterclockwise  to reduce  the 
brightness  and also  blur  the FOCUS. 
NOTE  For  usual  observation,  leave the following  non-calibrating 
function  section set to ''CAL"  position. 
VARIABLE  Rotate 
in the  direction  of arrow. 
In  this  case,  the VOLTS/DIV  is calibrated  to 
its  indicating  value. 
SWP  V AR  Leave 
the knob  in depressed  state. 
In  this  case,  the  TIME/DIV is calibrated  to 
its  indicating  value. 
Align  the bright  line with  the horizontal  scale line at the 
center  of the  screen  by operating  CH J POSIT  ION. In some 
cases,  the bright  line may  be oblique  to the  scale  slightly  by the 
effect  of earth  magnetism.  In this  case.  bring  the bright  line 
until  it lies  on the  horizontal  scale line at the  center  of the 
screen  by properly  adjusting  the semi- Gxed  variable  resistor 
TRACE  ROTATION  on the  front  panel. 
18  GENERAL 
MEASUREMENT 
(I)  In the  case  of observing  a single  waveform. 
Use  CHI  or CH2  when  not observing  the phase  difference 
between  two waveforms  or when  engaging  in a operation 
other  than X- Y  operation.  Make the following  settings 
when  using CHI . 
MODE  Switch  of Vertical  defection  system CHI 
MODE  Switch of TRIG 
AUTO 
TRIG  SOURCE 
CHI 
Under  these settings,  almost all the  repetitive  signals of 
about  30 Hz  or more  applied  to CHI  can be synchro­
nized  and observed  by adjusting  TRIG LEVEL.  Since 
the  MODE  of horizontal  axis is at  AUTO  position,  the 
bright  line appears  even when  no signal  is present  or  when 
input  coupling  switch is at  GND  position.  This means 
that  the measurement  of DC  voltage  can be measured.  The 
following  switching is needed  when observing  low  fre­
quency  signals of about  30 Hz  or less. 
MODE  of TRIG 
ORM 
Synchronization  can be effected  by operating  LEVER knob 
under  this setting. 
When  using only CH2,  use the instrument  after making  the 
following  settings.  
						

							MODE  Switch 
of Vertical  Axis 
TRIG  OURCE 
(2)  When 
observing  two wavefonns  CH2 
CH2 
Observation  of two  wavefom1S  can be made  easily  by 
setting  the MODE  switch of vertical  axis to ALT  or CHOP. 
When  observing  two wavefonns  of high  repetition  frequen­
cies,  set the  MODE  switch to ALT  and, in the  case  of low 
frequencies,  set it to  CHOP. 
Measu rement  of the  phase  difference  is per formed  after 
effecting  synchronization  with leading  phase signal. 
(3)  When  observing  wavefonn  with X-Y 
Set  the MODE  switch of vertical  defection  system  to CH2 
(X- Y) and  TIM E/DIV  switch to X-Y.  Then  the instrument 
works  as an  X-Y oscilloscope. 
Each  input  is applied  to the  instrument  as follows. 
X-axis  signal (horizontal  axis signal) 
Y  -axis  signal  (vertical  axi� signal)  CHI 
INPUT 
CH2  INPUT 
In  this  case.leave  the horizontal  axis magnification  switch 
(PULL-MAG  x 10  inner  shaft knob)  at depressed  position.  7. 
METHOD  FOR CONNECTING  SIGNALS 
The  first  step of measurement  is to  introduce  the signal 
desired  to measure  to the  oscilloscope  properly. Do it with 
utmost  care. 
(I)  When using  a probe 
Use  the attached  probe, AT-I 0  AK  I  .5, when  measuring  a 
high  frequency  wave with high accura cy. 
It  should  be noted,  however,  that since  the input  signal  is 
attenuated  by this  probe  to 1/10  before  it is input  to the 
oscilloscope,  the use of the  probe  is disadvantageous  for 
low  signals,  and that at  the  same time,  the measuring  range 
is  extended  by that  amount  for high  signals. 
 
o  Do  not  apply  a signal  which exceeds  250V (DC+  peak 
AC  at I kHz). 
o  Bring  the grounding  point of the  earth  lead wire  of the 
probe  close to the  point  to be  measured  when measur­
ing  a rapid  rising  signal  or a high  frequency  signal. Long 
earth  lead wire  may cause  wavefonn  distortions  such as 
ringing  and overshoot. 
19  
						

							Connection 
of earth  lead wire 
20  (a) 
A good  example  (b) 
A bad  example 
For  better  measurement.  it is required  to use  an earth 
attachment  available at option. 
Multiply  the reading ofVOLTS  DIY by 10. 
For  example.  if the  VOLTS/DIY  ts SOmV/DIV.  then 
read  the wavefonn  as 
SOmV/DIV  x 10  = SOOmV/DIV 
o  To  avoid  measurement  error, put the probe  in the  follow­
ing  correction  state and check  it before  measurement 
without  fail. 
Connect  the tip of the  probe  to the  output  tenninal 
CAL  O.SV  of I kHz  calibration  square wave voltage. 
When  this correction  capacity value is at  optimum,  the 
wavefonn  takes the shape  as shown  in Fig.  (a) as follows.  If 
the  wavefonn  is as  shown  in Fig.  (b) or Fig.  (c), 
rotate  the semiftxed  adjusting  screw on the  matching 
box  of the  probe  by using  a screwdriver  until the opti­
mum  state is obtained. 
L Capacitance  correction  trimmer 
JliUlJ1  MJUl  MM 
(a)  Optimum  (b) 
Capacity  too 
small 
(2)  At time  of direct  connection  (c) 
Capacity  too 
large 
When  connecting  a signal  directly  to the  oscilloscope  not 
usmg  the attached  probe AT -10  AK  1.5 (I O·  1 ),  pay  atten­
tion  to the  following  points in order  to minimize  the mea­
surement  error. 
o  When  perfonning  observation  using a bare  lead wire,  no 
trouble  occurs on the  circuit  to be  measured  at low 
impedance  and high level. 
However.  note that,  in most  cases.  measurement  error 
may  be caused  by static  stray coupling  with other  circuit 
and  power  line. 
This  measurement  error cannot  be ignored  even in low 
frequency  region.  
						

							In 
general.  tt tS safe  to avoid  measunng  with non­
shielded  connecting  wire. When  using a shieldmg  wire, 
connect  one end of the  shield  to the  earth  terminal  of 
the  oscilloscope  and the other  end to the  grounding  of 
the  circuit  to be  measured.  It is deirable  to use  a coaxtal 
cable  with B  C  type connector. 
The  following  cautions must be observed  when per­
forming  a wide  band measurement.  It ts necessary  to 
terminate  with the characteristic  impedance of the  cable 
when  measuring  a rapid  nsing  waveform  or a high  fre­
quency  wave. 
Especially  when using a long  cable.  the absence  of a 
terminating  resistor will necessarily  lead to a measure­
ment  error derived  from ringing  phenomenon.  Some 
measunng  circutls require a term  mating  reststor  equal to 
the  charactensttc  unpedance of the  cable  also on the 
measurement  terminal stde. 
B  C  type terminating  reststor (50 Q) ts conveniently 
used  for this  purpose. 
c  In  order  to perform  measurement  with the measuring 
circuit  put in proper  operating  state, it is sometimes 
necessary  to terminate  the cable  with  an impedance 
which  corresponds  to the  circuit  to be  measured. 
o  The  stray  capacity  of the  shield  wire must  be taken  in 10 
account  when performing  measurement  with a long 
shield  wire. Since  the shield  wire normally  in use  has  a 
capacity  of about  I 00  pF  per  meter.  its effect  on the 
circutt  to be  measured  cannot be ignored.  Use a probe  to 
minimize  the cffection  the circuit. 
When  the length  of the  shield  wire is used  or when  the 
length  of the  non-terminated  cable reaches  I  4 wave 
length  or its  multiples  within the band  of V-:!09  type 
(I  4 wave  length  is about  3 meter  when using a coaxial 
cable  at }0  MHz),  oscillation  may be caused  near 5 mV 
DIY  range. 
This  is caused  by the  resonance  between the externally 
connected  high-0 inductance  and the input  capacity 
and  can be avoided  by reducing  the  Q. 
Connect  the cable  or shield  wire to the  input  connector 
by  way  of a  senally  connected  I OOU  to I  n  reststor,  or 
perform measurement  at other  VOLT/DIY  range. 
21  
						

							8. MEASURING  PROCEDURE 
The  first  things  to do  are  as follows. 
o  Bring  the brightness  and FOCUS  at optimum  positions 
for  easy  read out. 
� 
Display  the waveform  as large  as possible  to minimiLe 
the  read  error. 
Check  the capacity  correction  when using a probe. 
(Refer  to paragraph  (I) "When  using a probe"  of Sec­
tion  7. "Method  for connecting  signals" for correcting 
capacity.) 
(I)  DC  voltage measurement 
Set  input  coupling  to G  D  and decide  the zero  level prop­
erly. 
Set  VOL  TS/DIV  appropriately  and set AC-G  D-DC  to 
DC.  Since  the bright  line shifts  here by the  amount  of 
DC  voltage,  the DC  voltage  of the  signal  can be obtained 
by  multiplying  the shift  width  by the  indicated  value of 
VOLTS/DIV.  When VOLTS/DIY  is 50  mV/DIV,  then 
SO  mV/D IV  x 4.2  = 210mV  (However,  if the  probe  AT-
10  AK  I.S (10:1)  is in  use,  the true  value  of the  signal  be­
comes  10 times  of the  value,  or SO  mV/DIV  x 4.2  x 10 
=  2.1V.)  DC 
voltage  (after shifting) 
Zero  level (reference  line) 
(2}  AC voltage  measurement 
The  same  as paragraph  8 (1).  "DC  voltage  measurement", 
but  here  there  is no  need  of align  the zero  level  with  the 
scale  line. Set the zero  level  to the  position  that can be 
easily  observed. 
In  the  drawing  as follows,  VOLTS/DIV  is IV/DIY,  IV/ 
DIY  x S =  S Vp-p  (SOVp-p  at time  using  the probe  AT-
10  AK  1.5(10 : 1)).  When  magnifying  and observing  a small­
amplitude  signal, superimposing  on a high  DV voltage, 
set  the  input  coupling  to AC.  The  DC voltage  is cut  off and 
AC  voltage  can be observed  by increasing  sensitivity.  
						

							r/f\ ----�ff\ --
1\ I 1\ 
\17  1\ 
H--+--f--t-1-t-+---+-_+=1_  -- ---
(3)  Measurement  of frequency  and period 
This  will be explained  with the following  figure. 
One  period  covers the time  A and  time  B, which  are  sepa­
rated  from each other  by 2.0  DIY  on the  screen. 
When  the sweep  time is I ms/DIY,  the period  is given  by 
1  ms/DIV  x 2.0  = 2.0  ms 
=2.0  X 10-3  S 
Accordingly,  the frequency  is 
1/(2.0  X J0- 3)=  500Hz 
(However,  when the knob  MAG  x!O is at  pulled  out posi­
tion,  TIME/DIY  must be converted  to I /10  since  the sweep 
is  magnified.) 
I-+--1--I-�. *  • 
--
- ----
--7 1\ f/ l 
I-
T\ II\ 7 1\ 
1/ 
I\ rr ., u 
-- - -
Time  A Time 
B 
II \ 
- -
-
1-
-lh__: 
v � 
I-
(4)  Measurement  of time  difference 
Triggering  signal source  ''SOURCE"  is selected  as an  offer­
ing  reference  signal when measuring  the time  difference  be­
tween  two signals.  Assume  that pulse  trains  as shown  in (a). 
Then  (b) shows  the case  when  CHI is taken  as the  triggering 
signal  source  and (c) the  case  where  CH2 is taken. 
I  I 
CHI� 
CH2�­�- (a) 
(b) 
I 
I 
-_I 
,- +-.:::.CH:..:...:..I 
__ _ I 
CH2 
(c)  23  
						

							24 This 
means  that CHI  is used  as the  triggering  signal  when 
investigating  the length  of time  by which  the signal  of CH2 
is  delayed  from the signal  of CH 1.  C H2  is  used  in the 
reversed  case. In other  words,  the signal  leading  in phase  is 
selected  as the  triggering  signal source. 
If  this  process  is reversed,  the portion  to be  measured  may 
sometimes  not appear  on the  screen.  Thereafter,  equalize 
the  amplitudes  of the  two  signals  appearing  on the  screen  or 
superimpose  one on another. 
Read  the time  difference  between 50% amplitude  points 
of  the  two  signals. 
Sometimes  the superimposing  method is more  convenient 
from  the point  of view  of procedure. � it'----� Time 
=>  difference  Equalize 
"' 
��amplitud es 
- - ---
J _-:;-by  V AR 
( a)  Equal  amplitude 
measuring  method 
  (b) 
Suerposition 
measuring  method 
Since  the pulsed  wave contains  many high-frequency  wave 
components  (higher harmonics)  depending on its width  or  period, 
pay the same  attention  as given  to high  frequency 
signals  when handling  it. Accordingly,  use a probe  or coax­
ial  cable  and shorten the  earth lead wire  as much  as possible. 
(5)  Measurement  of rise  (fall)  time 
To  measure  the rise time,  pay attention  not only  to the 
abovementioned items  but also  to measurement  error. 
The  following  equation is provided  for the  relation  among 
the  rise  time  Trx of the  wavefom1  to be measured,  the rise 
time  Trs of oscilloscope,  and the rise time  Tro displayed  on 
the  screen. 
Tro  =../  Trx2  + Trs2 
When  the rise  time  of the  pulse  going  to be  measured  is 
sufficiently  longer than the rise time  of the  oscilloscope 
(17.S ns in our  case),the effectofthe  rise  time  of the  oscil­
loscope  on the  measurement  can be neglected.  However, if 
both  are close  to each  other,  measurement  error may be 
caused. 
The  true  rise time  is given  by 
Trx  = 
.../  Tro2  - Trs2 
Moreover,  in general,  in a circuit  free from  waveform  dis­
tortion  such as overshoot  and sag,  the following  relation­
ship  is established  between frequency  band and rise time.  
						

							f
c  x  tr  =  0.35 
Where,  f
c :  Frequency  band (Hz) 
tr:  Rise  time  (s) 
The  rise time  and fall  time  are determined  by the  time 
elapsed  between  the I 0'1  to 9Qc,r  \'a lues  of pulse  width. 
(6)  Synchronization  of complexed  waveform 
In  the  case  shown  in the  Fig.  (a) below  where  two wave­
forms  have difference  in amplitude  alternate. the wave­
form  is doubled  if the  trigger  level is not  set properly.  In 
the  case  where  the trigger  level is selected  as Y line  two 
waveforms.  one starting  with A and  advancing  to B.  C.  D,  E. 
F ....  and the other  starting  �ith E and  advancing  to F, 
G.  H, I  ....  will appear  alternately  on the  screen.  They 
will  be doubled  as shown  in Fig.  (b),  for which  no synchro­
nization  can be taken. 
In  such  a case,  rotate  LEVEL  clockwise  until the trigger 
level  comes  to Y'  line.  Then  the waveform  on  the screen  be­
comes  the one  shown  in F1g.  (c)  above  wh1ch  starts with 
B  and  advances  to  C,  E.  r, ...  and  which  allows  synchro­
niLation.  \/TC\ .. 7\ h/"'-� 0\ �� 
� v J.......,. L� p= 
(a) 
Signal  waveform  Y' 
Trigger  level 
y  �Lting  line 
(b)  When  the uiggc r  (c) 
When  the uigger 
...:ning  level •� Y  selling 
level i' y· 
Synchronization  of complexed  waveform 
(7)  How  to use  TV  exclusive  synchronization 
CD  On the image  waveform  of TV 
In  the  work  concerned  w1th TV. comple:-.ed  signals con­
taining  video signal.  blanking  pedestal signal. and syn­
chronizing  s1gnal are often  measured.  llowever,  since 
the  waveform  is complexed,  a special  circuit IS needed 
10  effect  a stable  syncrhonization  with vertical  waveform. 
Synchronizing  signal  pulse 
(SYNC  pulse)  IV 
(vertical)  ------� 
25  
						

							26 Q) 
Difference 
in the  circuits 
Exclusive  circuit for conventional  oscillograph 
General  circuit 
Video  �ignal 
To  trigger  circuit 
Hard  to synchronize,  because 
video  signal  is applied  directly 
as  trigger  signal.  Simple 
synchronizing 
circuit 
To  trigger  circuit 
Synch ronization  is more  easily 
effected  than  in the  circuit 
shown  at left,  because  the 
signal  is integrated  to remove 
high  frequency  components.  Exclusive 
circuit for this 
instrument 
(Principle  drawing) 
TV  exclusive  synchronizing 
separator  circuit 
To trigger 
cucuit 
After  picking  up the  SY  C pulse, 
the  vertical  synchronization  is 
separated.  Then, the stable  syn­
chro nization  is obtained.