Tektronix SC 502, Instruction Manual

Page: 60 / 127

CRT Shield
1 8 78-7
Ag. 5-2. CrOll lectlonal view
Ihowlng placement POliti
on of 'ront
crt IUpport, crt shield and crt.
2 . Remove all the k nobs except the
SLO PE. LEVEL
and
horizontal PO S I T I O N .
3 . Rem ove t he two
screws ( 1 7)
which hol d t he circuit
board
assem b l y
to the top rails.
Rem ove
screw
( 1 8)
and
st ud
post
with k nurled n ut
( 1 9) and
rem ove bottom section
frame
( 20).
4 . Remove a n y n uts and washers
holdi ng the
controls
(from
w hi ch the knobs have been
removed)
to
the
front
subpanel ( 1 4)
and
front panel (21 ) .
Discon nect from the
circuit boards those connectors w hose leads go to
t he
front- panel connectors or control s whi ch
s
t
i
l
l have knobs.
5. SI i de t he ci rcuit board assem bly away from the front
subpanel unti l it is
clear.
@ MAY
1 980
Malntenance-SC 502
6. Disconnect the pl ugged-together ci rcuit board
assem bly as
required.
B. I NSTALLATI O N
1 . Reverse the Circuit Board Rem oval procedure. t hen
follow t he
CRT
Repl acement procedure.
Variable Trigger Holdoff/Varlable Sweep Tim e
The knob i n the center of the Time-Div switch i s
norm ally used for varyi ng t h e t i m e per
divi s i o n
setti ngs of
t he sweep generator. Figure 5-3 shows the
jumper change
necessary
f
o
r
changi ng the fu nction of t his knob to a
variable trigger hold-off
adj ustment.
T h i s is usef ul when
tri ggeri ng on irregular waveform s.
For variable trigger holdotl let pin 1
( .. ) end o.
the
jumper
at the HO
marked end.
For variable SECONDS/DIV set pin 1
( ... ) end
o. the
jumper
at the SWP
marked end.
Main Circuit Board.
1 8 7 8 · 34
Ag. 5-3. Variable Trigger Hold Off-Variable Sweep TIme
jumper
placement
5·3