Tektronix 545 Use and care manual

Type 545 Oscilloscope
CALIBRATION AND MAINTENANCE PROCEDURE
Additional copies ay be ordered through Tektronix, Inc. field offices and
overseas representatives. Specify Stock No. 070-282. Price $2.00, postpaid
in the United States.
©Copyright 1961, Tektronix, Inc. Reproduction without written per ission of
copyright owner prohibited. Per ission for li ited reproduction of Section IV
(Calibration Record) will be granted on request.
BMarch 15, 1961

Third Printing, May 1962
Changes:
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Tektronix Type 5^5 Oscilloscope
Calibration & Maintenance Procedure
070-282
Supplement
May, 1962
The enclosed pages contain revisions and corrections to the Tektronix
Type 5^5 Calibrat ion and Maintenance procedure Edition B. Remove and
destroy old pages. You may already have revised page 3*30 (Rev 8-61)
if so, you may throw away the copy enclosed.
dditional copies of this supplement may be obtained through your
Tektronix Field Office or Overseas Representative.
Tektronix, Inc.
Field Information Dept.
Copyright (c) 1962, Tektronix, Inc.

Changes:
Third Printing, May 1962
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BBREVI TIONS
C.F. or cf Cathode-Follower Spec Speci f?cat ion
CRT Cathode-Ray Tube Trig Trigger
CW Clockwi se V. . or V Vertical mplifier
CCW Counterclockwi se VVolts
D.S. or Del 1g Swp Delaying Sweep
D. . or D Distributed mplifier
Ext External
HV High Voltage
1 nt 1nternal
kc Kilocycle (103 cycles)
kkilohm (10^ ohms)
M.S. Main Sweep
nf microfarad (10"^ farad)
Hiaf micro-microfarad (10“ ^2 farad)
|isec microsecond (10"6 second)
me megacycle (10^ cycles)
mm millimeter (10“3 meter)
msec millisecond (10“3 second)
mv millivolt (10“3 volt)
M.V. Multivibrator
nsec or mpsec Nanosecond or millimicrosecond (10“9 second)
aOhms
p/n Part Number
P-P Peak-to-Peak
pf or ppf Picofarad (10“'2 farad)
RMS Root-mean-square
S/N Serial Number
(Revised 5-62)

SECTION 3
C LIBR TION ND M INTEN NCE PROCEDURE
0 GENER L INSTRUCTIONS
0.1 USING THE PROCEDURE: s far as possible, each step in this procedure
is divided into three main parts: Measurement, djustment, and Trouble
shooting. The calibrator needs only to proceed within the step far
enough to secure specified performance, and may skip the remaining portions.
0.2 TROUBLESHOOT ING: The troubleshooting procedure normally is arranged in
order of probable causes: These should be checked out in the order
given. In a few cases, involving high-value or hard-to-replace compo
nents, procedures are arranged as a process of elimination.
0.3 C UTION: Steps are arranged to minimize interaction effects
and the necessity for "backtracking". ny trouble-shooting should
always start with a check of the power-supplies, and a complete
recalibfation should always follow the indicated order so that
calibrations made first are not thrown off by later adjustments.
0.3.1 Example: djusting the low or high voltage power supplies
after calibrating the sweep or vertical will require a
complete recalibration of both sweep and vertical.
O.k USING THE C LIBR TION RECORD S GUIDE: fter the calibrator has
become familiar with the attached procedure, the Calibration Record
Section k can become his primary guide for a complete calibration,
and only occasional reference need be made to the more detailed
and involved test of the procedure.
0.5 ENTRIES IN THE C LIBR TION RECORD: Three types of entries are indicated
for the Calibration Record (Section k) ("Cal Record") in the procedure.
"Note" generally indicates the calibrator should enter "good" "fair"
"poor" "0K" "NG" or other appropriate comment in the space provided.
"Check" usually calls for simply marking the record to indicate the
performance of a step. "Log" calls for the recording of some specific
figure (voltage, time, error, dial setting, etc.) in the appropriate
space. In addition to the entries called for in the procedure, all
parts replaced during calibrat ion and troubleshooting, (perhaps with an
indication of the defect), should be recorded in the right hand margin
in the spaces provided. Generally they can be identified by their
schematic symbol (e.g., V20, V58, R265, etc.).
n index to Section 3 wi11 be found on the reverse of this page.
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3-1

SECTION 3
INDEX
Starts On Page
1. Physical Checkout ........................................ ........ . 3-2
2. Power Supply.......................................................3-3
3. Calibrator (Set).............. .. ........... 3-1^
k. High Voltage Supplies ................ .............. ........... 3-15
5. Miscellaneous Functions ........ . ................................. 3“ 17
6. CRT, Focus and Intensity Circuits ..... ................. .......... 3-18
7. Main Vertical mplifier— Initial lignment ........................ 3-22
8. Calibrator (Divider) ...................................... 3”31
9. Trigger Circuits, Main Sweep .......... .. ......... ............... 3-33
10. Trigger Circuits, Delaying Sweep ............... 3“39
11. Sweep and Horizontal mplifier Calibration ........................ 3-i*3
12. Delay and Lockout System ................................... 3”5^
13. Delaying Sweep Calibration ............ ... .............. . ........ 3-60
1 if. Hoi doff System ................................................ 3-62
15. Vertical mplifier and Delay Line Compensation .......... 3-63
16. Front Panel Waveform............................................... 3“73
17. Z- xis Input............................................. 3~7^
3-1 C LIBR TION ND M INTEN NCE PROCEDURE 5-62

7.1.3 Cathode Interface Check: Install Type (53/54) P Plug-in and pre-set front-panel
controls as follows:
Stability
Triggering Level
Ti e/C
Multiplier
Magnifier
Triggerable
0
. 1 psec
2
Off
Horizontal Display
Trigger Slope
Triggering Mode
Coil Current
A plitude
Main Swp Nor .
+lnt
AC Fast
On
3 O'clock
Install viewing hood. Adjust Triggering Level control for stable display with trigger-
point about l/2 c ahead of rising portion of wavefor (See Fig 7-2). Adjust
A plitude control for about 3 c display, and position leading edge near center of
graticule.
7 .1.3 .1 Driver Stage Check: Exa ine the wavefor for a sharp dip i ediately
following the leading edge (See Fig 7-3), indicating possible defect
in driver-stage tubes. Adjust line voltage to 105 v for 10-15 seconds,
then to 125 v. If the "notch" appears to change a plitude with changing
line voltage, try replacing the driver stage tubes (in early instru ents,
V I050 and V I052; in later instru ents above s/n 9291, V I033 and V I043).
Return line voltage to 117 v.
Fig. 7-2 P Unit Display
at 0.2 psec/c . Fig. 7-3 Effect of defective
driver-stage tubes, 0.2 psec/c .
7.1.3.2 Input Stage Check: Reduce sweep speed to 0.5 psec/c . Exa ine wavefor
for slope in first c following leading edge (Fig. 7-3). Check for effect of
line-voltage change on slope. If line-voltage affects slope, try replacing
input a plifier tubes (6AW8's or l2BY7A's) with aged and checked tubes
fro sa e subgroup. If tubes are replaced, repeat Step 7.1.
Fig. 7-4 Effect of "cathode Fig. 7-5 Rolloff defect in
interface" in V.A. 0.5 psec/c . D.A. tubes. 0.5 psec/c .
7J .3.3 Distributed A plifier Tube Defects: If tube replace ent in 7.1.3.2 does
not eli inate changes in slope (Fig. 7-4 or 7-5) with line-voltage change,
distributed a plifier tubes (6CB6's or 6DK6's) will require replace ent.
(Do not ix tube brands.) Use of 6DK6's is no longer reco ended
(SN 9292 - up). Replace with type 8136 (Tektronix p/n 154-367).
See page 5-0.
Now, turn P-Unit "off". Center the trace and check voltage at each
suppressor grid in the distributed a plifier for +175 v. Replace any tube
which does not read at least 165 v at the suppressor grid. (If tube re
place ent does not correct voltage, check suppressor bypass capacitors.)
(Revised 5-62) CALIBRATION AND MAINTENANCE PROCEDURE 3-23

7.2 VERTIC L B L NCE:
NOTE: It will be necessary (where specified) to use a
"resistive shorting bar", consisting of a ^ -ohm 1/2
watt composition resistor attached to some convenient
insulating handle, for shorting grids together. Use
of clip leads or wires will introduce enough inductance
to cause oscillation, usually at a frequency far beyond
the amplifier bandpass. These oscillations are rectified
in the amplifier and appear on the CRT as DC level
changes, making balance measurements impossible. The
resistor lowers the Q of the inductive circuit below
the point where oscillations can occur.
7.2.1 Overall Balance: Free run the main sweep at 1 msec/cm or faster.
Locate CRT electrical center by shorting the vertical deflection
plate pins together (NOT to ground). Note graticule position of
electrical center and remove jumper. Now position the trace
back to CRT electrical center, using vertical position control.
Now, use the resistive shorting bar (if test load unit is used,
press "zero reference" button) to jumper the main amplier input stage
grids together. Connect the shorting bar between pins 1 and 3 of
the plug-in interconnecting socket. Log trace displacement from
CRT electrical center in Cal Record. If 1 cm or less, skip
7.2.2 for the moment (it may be necessary to come back to this later).
If more, complete 7.2.2.
7.2.2 Vertical Balancing:
7.2.2.1 Distributed mplifier Stage: Use a short cliplead to jumper
the distributed amplifier grid lines together (the two
distributed lines running outside the rows of tube sockets,
connecting with pins 1 of the D tubes).
(C UTION: Do not short to ground).
If trace-shift from electrical center is 2 mm or less, log
in Cal Record and proceed with 7.2.2.4. If more , complete
7.2.2.2-7.2.2.3.
7.2.2.2 D. . Bias: gain jumper D grid lines. Use DC voltmeter to
measure grid-to-cathode bias for each tube pair. For each
pair, measure from jumper to either cathode (pin 2) of each
pair. For S/N 101-9291 (and 9292-11691 with original tubes*)
bias should be O.9-I.6 volts. For later instruments, 1.0 v
minimum to 2 v max. Replace one or both tubes of each out-
of-tolerance pair. For S/N 101—9291> use checked 6CB6's,
Tektronix p/n 157-037. For S/N 9292-up, select "raw" Type 8l3$is
but see* below. Log high and low bias values in Cal Record.
*6DK6 design changes in late 1958 require modification of instruments S/N 9292-11691
to use the new-style tubes. Modification kit 0^0-191 ($1.80) changes cathode
resistors in the 12BY7 stage to provide 1.0 v minimum bias on output stage, and
permits use of old or new 6DK6's or 81361s. To check doubtful instrument, examine Ri
& R1017— if 3k (5w5%) and 10 k (8w 5%), the instrument has already been modified.
For discussion of type 8136 tube, see page 5“0.
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3-21*