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Model 181A/AR
fully ecw.
Slowly rotate INTENSITY control cw to a
point where
no trace
blooming
appears.
Depress
NORMAL
push button;
do not increase. INTENSITY
while in NORMAL.
H sweepspeedis changed, always
check for proper intensity using the above procedure.
When not actively using the oscilloscope,
switch
to STORE
or VIEW mode,
thus
. turning off the write gun and eliminating
the possibility of burningthe storage mesh.
Whenin WRITE,
NORM,
or MAX W mode,
any
visible
trace
may
cause permanent
damage to the CRT if display is left for
prolonged periods oftime.
Topreventthis
from happening, periodically erasethe dis-
play or switch to STORE mode if you wish
to retain the image.
b.
For variable persistence operation, press the
WRITE
push button.
Use minimum INTENSITY
and
maximum
PERSISTENCE
compatible with display.
c.
UseMAX WRITE
mode only for fast sweeptime,
single
shot display,
or to improve the uniformity of
trace intensity.
The MAX W, mode causes more rapid
positive fading onthe CRT and persistence or storage
time of the display is thus reduced.
d.
To store a display,
pressthe WRITE push but-
ton, adjustthe INTENSITY and PERSISTENCE
for the
desired display,
and press the STORE
push button.
e.
Toviewastoreddisplay,
press thé VIEW push
button.
f. Tostore more than one display,
press the WRITE
push button,
set PERSISTENCE
fully clockwise
and
INTENSITY as required; allow first display to be writ-
tenontheC RT.
Set INTENSITY fully counterclockwise
andconnect the second signaltobe stored.
Reset ver-
tical POSITION
if second
display is not to be super-
imposed onfirst.
Slowly rotate INTENSITY clockwise
until second display appears.
Press theSTORE push
button.
g.
A display which is stored when the Model
181
A/AR power
is turned off will remain stored for sev-
eral days.
To redisplay the stored waveform, press
the STORE pushbutton,
turn POSITION controls fully
cew before turning power on.
Apply power to Model
181A/ARandallow 5 minute warm-up.
If stored sig-
02612-4
'Section HI
Paragraphs 3-44 to 3-47
nal was
written
in
WRITE
mode,
depress WRITE
pushbutton.
Ifstored in MAX W mode,
depress
MAX
W pushbutton.
Depress VIEW pushbutton to observe
waveform.
h.
To eraseall persistent or stored displays,
set
modetoWRITE
( or Max Write ) and then the ERASE
push button for approximately 2 seconds, thenrelease.
i.
If only a portion of a slow sweep display is de-
sired, press
the STORE
push button when the trace
has been writtentothe desired point; the write gun is
blanked and the written portion is stored.
j.
Use
a viewing
hood,
if desired,
to improve
sereen-display contrast.
3-44. SINGLE-SHOT OPERATION.
3-45. To write or store single-shot phenomena, a trial
setting of INTENSITY is the best approach.
The amp-
litude of the phenomena and the sweep-time required
todisplay itwillaffectthe persistence.
For example,
with maximum
PERSISTENCE
and some settings of
INTENSITY,
a single-shot straight-line may bloom.
A single-shot signal withamplitude variations may not
cause bloom.
To determine the best INTENSITY. set
ting, connect a signal which approximates the sweep
time andamplitude of the single-shot signalto be writ-
ten,
Set PERSISTENCE fully clockwise and trigger a
single
sweep ofthe test signal.
Set the INTENSITY
as far as possible without causing blooming.
Repeat
this procedure, varying the INTENSITY, until the proper
display is obtained.
This setup should give maximum
persistence to the single-shot display.
After the sig-
nal has been written,
press the STORE
push button to
retain the display.
3-46. Single-shot signals which require a sweep time
faster than 20 microseconds per division can be writ-
ten with more brightness by switching tothe Max Write
mode.
The screen will be unevenly illuminated after
erasing when in Max Write,
Figure 3-2B; however, IN-
TENSITY can be set high enough to make the display vis-
ible throughthe illumination.
A display writtenin Max
Write will be more rapidly obscured by positive fading
than a signal written in NORMAL.
3-47, Single-shot signals which require a sweep time
between 200 and 20 microseconds per division may
have low brightness at the center of the screen.
Fire
a single-shot test signal with INTENSITY and PERSIST-
ENCE fully clockwise and press the WRITE push but-
ton.
If center screen brightness is low, wait for one
to three minutes for the low brightness areato become
brighter.
Likewise,
if the entire display brightness
appears below a usable level,
or the display is not
visible at all, waitforonetofive minutes for the dis-
play to appear.
3-5
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