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
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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:
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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*

7.2.2.3 D. . Balancing; fter selection of tubes (if necessary)
for proper bias, recheck 7.2.2.1. If trace shift is still
greater than 2 mm from CRT electrical center, tubes of a
pair can be "swapped across" to achieve balance. If tubes
are swapped between pairs, or if further tube replacements
are required for balance, repeat 7.2.2.2. Log final balance
point, and reposition trace to this point.
If imbalance persists, check resistances of reverse term
ination network (plate loads) for symmetry (±2%). Check for
opens or shorts in individual suppressor-grid networks, and
for partial short to ground on one side of delay line.
TUBE REPL CEMENT NOTE: Do not reject 6CB6 or6DK6/8136 tubes because
of a slight blue glow (noticeable only in a darkened room) out
side the plate area. This is not necessarily an indication of
gas, but is caused by glass fluorescence where the envelope
is struck by the accelerated electron beam, and is normal in good
tubes. If in doubt, check tube in conventional gas-detection circuit.
Tubes should not be rejected for heater-cathode leakage unless it is
less than a few thousand ohms/These tubes normally show slight leakage.
7.2.2.k Driver Stage Balancing: Use the resistive shorting bar
to jumper the grids of the driver cathode-followers.
Select tubes if necessary for not more than 1/2 cm trace
shift from D imbalance point. In instruments above S/N 9291*
both cf stages must meet this specification. For optimum
balance with minimum tube selection, use Type ECC88/6DJ8 or
E88CC/6922 instead of Type 6BQ7 . If imbalance persists,
check cathode resistors for symmetry (±10%), and check
plate voltages, filament lines, etc.
7.2.2.5 Input Stage Balancing: Position trace to CRT electrical
center, and again jumper input stage grids as in 7.2.1. Trace
shift should be 1 cm or less. Install new checked input
tubes (6 W8's p/n 157”039 or 12BY7 's p/n 157-053 — See
footnote, 7.1.2) if necessary. If imbalance is less than
1/2 cm from driver-stage imbalance point, but more than
1 cm from CRT electrical center, try swapping positions
of the input tubes before replacing with new ones.
If input stage imbalance persists, check values of plate
load resistors for symmetry; also cathode resistors.
Check components in DC Shift compensation networks(tiny
68 k resistors connected to input stage plate loads, etc.).
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3"25

7.3 LINE RITY: Install Dual-Trace plug-in. Free run main sweep at 10 psec/cm.
Position trace to top and bottom of visible scan. If necessary, remove
graticule cover and use white nylon cam to adjust graticule so ruled portion
is exactly centered in area of usable scan.
7.3.1 Compression (linearity) Measurement: Set vertical Volts/Cm to
5, and display exactly 2 cm of calibrator waveform (adjust Variable
volts/cm if necessary), centered vertically. Position the display up
to the top graticule line and note any compression or expansion
(Spec: 0.5 mm max). Now, position the display so it "rests" on the
bottom graticule line, and note compression or expansion. If
within spec, log measured figures on Cal Record.
7.3.2 T roubieshooting:
7.3.2.1 Compression at Top and Bottom; Expansion at Top and Bottom:
Check to see if compression or expansion is the same at
the edges of the graticule as at the center. If not,
reset Geometry (6.3). If compression is uniform across
CRT, recheck D Bias (7.2.2.2) and CRT Deflection Factor
(6.4.3-6.4.4). Recheck regulated power supplies (2.3),
especially +350 v supply. Check DC level at pins 1 and
3 of plug-in connector for 67 ± 1 v.
7.3.2.2 Compression and Expansion: If trace shows compression in
in one direction and expansion in the other, recheck
vertical balance (7.2). Complete steps 7.2.2.1 through
7.2.2.5 if skipped before. If balance and bias are within
tolerance, try swapping CRT Vertical deflection plate
leads for inverted display. If directions of compression
and expansion are reversed, trouble is in vertical amplifier.
If they remain exactly as before, try replacing CRT, following
procedures in 6.4. Try another plug-in.
7.3.2.3 Persistent Troubles: If CRT change does not correct trouble,
try exchanging complete vertical tube complement from known-
good instrument of same serial range. Check screen and filament
circuits, vertical termination network, etc. Check for partial
short to ground in delay line. For instruments S/N 9292-11691»
check to see if modification kit 040-191 has been installed to
accomodate new type 6DK6/8136 tubes. In modified instruments,
R1016 and R1017 (in input stage cathode circuit) will be 3 k and
10 k respectively. See 7.2.2.2 and footnote. Install mod kit if
necessary. In rare cases compression has been caused by a bad CRT
shield. If all else fails, try installing a new shield.
(Revised 5“62) C LIBR TION ND M INTEN NCE PROCEDURE 3-26

7.4 D.C. SHIFT;
7.4.1 D.C. Shift Check: Use battery, or ohmmeter range of VOM to deflect
free-running trace 4 cm. Watch trace closely for 5“10 seconds.
If it drifts from its first stopping point,log amount and direction
of drift in Cal Record under "Initial" (re-check measurement by
noting drift during 5-10 seconds after removal of DC voltage).
If this drift is 1/2 mm or less, proceed to 7.5. If more than 1 2 mm,
complete 7A .2.
7A .2 D.C. Shift Compensation: Locate D.C. Shift Comp, control on main
amplifier chassis. Repeat 7A .1, making small adjustments of this
control. D.C. shift itself is a slow decrease in deflection; over
compensation will result in a slow increase in deflection.
Set compensation for as close to zero shift as possible. Recheck
at slow (2 sec/cm) sweep. Log final shift and direction in Cal
Record under "Final".
7 A A T roubleshooti nq: The D.C. shift compensation network consists
of the small 8.2 k resistors connected to the terminated end of
the output plate lines, the control itself, four 75 pf electrolytic
capacitors, the two 47 k resistors between capacitor sections,
and the small 68 k resistors connected to the plate load resistors
of the input amplifier stage.
7.4.3. 1 Inadequate Range of Control: Check the small resistors
first for correct value: They are likely to be damaged
by any severe power supply aberration.Check the electrolytic
capacitors for leakage or change of value. See that there
are no open spots in the control.
7A .3.2 Trouble Not in Compensation Circuit: If all compensation
network components are within tolerance, it may be necessary
to replace vertical amplifier tubes. If these are replaced,
be sure to repeat step 7.1, 7.2, and 7.3. lso recheck
proper operation of regulated DC supplies and vertical amplifier
filament ci rcui ts.
7A .3.3 Wrong Time-Constant: (S/N 9292 and up): If new General Electric
6DK6/8136‘s are used and DC shift compensation appears
to have the wrong time-constant (irregular drift of trace),
replace 8.2-k resistors with 6.8 k 1/4 watt 10% resistors.
General Electric and other tube brands should
not be mixed in the distributed amplifier.
(Revised 5”62) C LIBR TION ND M INTEN NCE PROCEDURE 3-27

7.7 G IN SET:
7.7.1 Maximum Gain: Install EP53 Gain dj dapter between plug-in
and scope, or install TU-1 (or TU-2 set to 1:1) Test Load Unit.
pply 200 mv of calibrator signal to banana jack on EP53 or to TU-1
or TU-2 input. Turn Gain di control for main vertical amplifier
(facing down on amplifier chassis) full clockwise. Log vertical
deflection. If more than 2.2 cm (10% reserve gain) proceed with
7.7.2. If less than 2.2 cm but more than 2 cm, the scope may be
usable for some purposes, but difficulty may be encountered in
making proper risetime and bandwidth (Step 15). If less than 2 cm
proceed with 7.7.3.1.
7.7.2 Set Gain: If maximum gain is adequate, reduce setting of Gain dj
control for exactly 2 cm deflection with 200 mv calibrator input.
(If TU-2 is used, set toggle switch to "250:1" and apply 100 v from
calibrator. Reduce setting of Gain dj for exactly 4 cm deflection).
7.7.3 T roubleshoot i ng:
7.7.3.1 Insufficient Gain: Check stage gains with a regular voltage-
measurement plugin in the instrument under test, to assure
even phase-splitting ahead of the main vertical amplifier in
put. Measure ampli tude at each grid, compari ng gai n agai nst
the table below.
mpli fier Stage Gain
12BY7 or 6 W8 Input mp (Gain dj Mi n Normal
Clockwi se) 4 - 4.5 5.5 - 6
6BQ7/6DJ8 CF Stage* 0.7 0.7
Distributed mp (6CB6's or 6DK6's) 20 - 22 22 - 24
* bove S/N 9292, 0.7 gain is total for both CF stages.
If both input and output stages are at or near minimum gain,
tubes in one or both stages may require replacement.
If overall amplifier gain is 70 or more, the trouble is probably
not in the amplifier, and may be in CRT sensitivity. Recheck HV
supplies (4.1) and Deflection Factor (6.4).
If V tubes are changed, be sure to repeat all parts of Step 7.
If tube-change does not provide correct gain, check plate load
resistors, screen potentials, decoupling networks, filament lines,
etc. lso check calibrator accuracy (Step 8), and input DC level
(7.1.2).
7.7.3.2 Gain Setting Unstable: Check Gain dj control for intermittency.
Check for changes in input stage grid DC level. Check decoupling
circuits, electrolytic capacitors and DC shift network components
(7.4.3). Monitor for power supply fluctuations, and intermittent
plate or cathode resistors. Try using Calibrator signal from
test scope, in case intermittency is in calibrator. Check V tubes
for gas (but see note in 7.2.2.3).
C LIBR TION ND M INTEN NCE PROCEDURE 3”30
Revised 8-21-61

9.2.3.k Trigger Sensitivity — continued; If a bright burst of sweeps
occurs as the spot passes slowly over the triggering point, or
if sweep is triggered on both upward and downward passes for
either slope setting, Trigger Sensitivity setting is too high.
dvance Stabl1i ty control until sweep just free runs with no ver
tical input, then back off just slightly. dvance Trigger
Sensitivity if necessary, until double-triggering or burst
triggering occurs, as described above. Now, back off Trigger
Sensi ti vi ty until neither aberration occurs as spot is positioned
past triggering point on either slope setting. Then back off
10-15° further.
Reapply 60 cycle waveform, reduce intensity (and reduce Time/Cm
setting if desired) and touch up Trigger Level Centering as in
9.2.3.3.
9.2.3.5 Preset Stability: In instruments equipped with this feature,
turn Stabi1ity control counterclockwise into "Preset" switch
position, turn Trigger Slope to +Line and Main Sweep Time/Cm
to 10 psec/cm. With no vertical input, a dim trace will appear
if circuit is already in adjustment. Locate Preset Stabi1i ty
control on sweep deck just behind front panel. Rotate this
control throughout its range and note the settings for no trace
(lockout), dim trace (triggerable) and bright trace (free-run).
Set the control to the middle of the "triggerable" range.
9.2.3.6 utomatic: Set front-panel Stabi1ity control to "Triggerable"
range (not necessary in later instruments with "preset" feature),
turn Triggering Mocfe to utomatic (or " C uto"), Trigger Slope
to +lnt, and Time/Cm to 10 psec/cm. dim trace should appear,
and should brighten very slightly when Trigger Slope is changed
to +Line. Return to internal triggering and 1 msec/cm sweep,
and apply 1 v of calibrator waveform to vertical input with
vertical Volts/Cm at 10. stable 1 mm display should result.
See that stable triggering on the proper slope occurs in +lnt
-Int slope settings.
9.3 FIN L CHECKOUT: REMOVE JUMPER installed in 9.2.3.1, and increase Calibrator
output to 2 v. Set Triggering Mode to C Slow and adjust Triggering Level
if necessary to obtain triggered display. t some Triggering Level setting
near "0", it should be possible to switch back and forth from + to - slope and
obtain stable triggering. Log the minimum size signal which can be displayed
trigged on either slope without readjustment of the Triggering Level. Switch
to C Fast and repeat procedure. Switch to DC mode and reposition display as
required for switchable triggering as above (minimum signal here will be
larger than for C slow because of the DC divider circuitry). Touch up circuits
again if necessary, to meet the following specs:
Internal (Calibrator Wave-form):
C Slow and C Fast: 2 mm signal anywhere within graticule, switchable
with Triggering Level at "0".
DC Mode: 2 mm signal within 2 mm of graticule center,
switchable with Triggering Level at "0".
External (Calibrator Wave-form):
C Slow, C Fast: 200 mv signal, switchable with Triggering Level at 0.
DC Mode'j 200 mv signal, switchable with Triggering LeveT
slightly clockwise from 0.
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3-35

ll.l.U Sweep mplifier Check: With the Magni fier on and sweep positioned as
in 11.1.3, rap sharply on the scope with your hand, watching for
horizontal microphonics. Now, turn Magni f ier off and on at about 5 sec
ond intervals, watching for slow drift after switching (DC Shift).
Repeat with sweep positioned far to the left. If microphonics or DC
shift appear, see 11.2.5. Check Cal Record if O.K.
11.1.5 Main Sweep Timing:
11.1.5.1 Calibration Check: Turn Horizontal Display switch to Main
Sweep Normal and obtain a triggered display of 1 mi 11isec
markers. Check timing over middle 8 cm as in 11.1.1.1, and
log any timing error at 9 cm mark in Cal Record.
11.1.5.2 Main Sweep Vernier (R99M) di: With display as in 11.1.5.1,
locate R99M on the Main Sweep Time/Cm Multiplier bracket.
C UTION: The screwdriver slot in this control is
at -150V. Use tool with insulated shaft for adjustment.
djust this control for exact Main Sweep timing over middle
8 cm of display. Note any adjustment in Cal Record.
11.1.6 Main Sweep Length: Remove vertical input and free-run Main Sweep
at 1 msec/cm. djust Sweep Length control (on bracket above main sweep
deck) for 10.5 cm sweep length. Log in Cal Record.
11.1.7 Sweep mplifier Fast Sweep Check: Free-run Main Sweep again, with
Horizontal Display Switch on Main Sweep Normal. Observe sweep length
as Time/Cm is turned to 0.1 psec/cm. If horizontal amplifier is func
tioning normally, sweep will lengthen appreciably to the right at the
fastest sweep rates. If sweep remains at 10.5 cm length or shortens at
fastest sweep rates, horizontal amplifier tubes may be too weak to
permit calibration of fast sweeps or CZkO and C25*+ are far out of adjust
ment. For either difficulty see 11.2.7.1.
11.1.8 Delaying Sweep Length; Turn Horizontal Display switch to Delaying Sweep
and turn off Main Sweep. Free-run Delaying Sweep at 1 msec/cm. With
Delaying Sweep Length control (concentric with D.S. Time/CM knob) clock
wise, check for 10.2 to 10.8 cm sweep length. Log in Cal Record. Now
turn Length control CCW, and check for 3.2 to 3.8 cm length. Log
actual length in Cal Record.
11.1*9 Sweep mplifier Gain: Turn Horizontal Display switch to Ext Sweep.
turn Magni fier on, and turn Stability Or Ext Sweep tten clockwise.
With tten toggle switch at XI, patch 1-volt Calibrator output to
Ext Sweep In and check for two-dot display. Dots should be spaced at
least 5 cm apart. Divide cm deflection into 1 and log in Cal Record
(volts per cm).
3-M*
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE

11.2.6 Timing Problems;
11.2.6.1 Delaying Sweep Won't Time: Try replacing Vl90, VI80 and/
or VI50. Recheck -150 v supply for correct voltage. If
Max Sweep Length (11.1.6) is off, recheck Horizontal Gain
(11.1.9). Try setting up basic timing on 2 msec/cm (timing
component check). If timing is not consistent, try replacing
R190 , B, C, before changing timing capacitor.
11.2.6.2 Main Sweep Won't Time; If R99M has insufficient range to
match Main Sweep to Delaying Sweep timing, the error may be
in Delaying Sweep timing, used to set Sweep Cal. See if
indicated Main Sweep timing error is substantially the same
in all ranges from 500 msec/cm to 100 psec/cm. If so, the
error is probably in the Delaying Sweep (see 11.2.6.1 above).
If not, try replacement of V90, V80 and/or V85 before changing
Main Sweep timing resistors or capacitors.
NOTE: Frequently, timing problems that seemingly
can be traced directly ,to specific timing resistors
are actually due to leakage or gas in sweep generator
tubes. lways try tube replacement first before
changing timing components.
11.2.7 Sweep Shortens at Fast Rates: If a free-running sweep fails to
lengthen at faster sweep rates, try replacing V265 and V272 (see
TUBE REPL CEMENT NOTE, previous page). If tube replacement does
not produce an increase in fast sweep lengths, C240 and C254 are
probably far out of adjustment, and will have to be preset before
fast sweep timing. Replace original tubes, and proceed with 11.2.7.1.
11.2.7.1 C240, C254 preset: Free run Main Sweep at 10 psec/cm.
Check probe compensation of test scope, and set test scope
to 50 psec/cm. Use test scope and probe to observe 150 v
sawtooth waveform at R.H. deflection plate of scope under
test (green/white coded lead from pin 8, V272 to deflection
plate).
djust C240 and C254 (located at the rear of the sweep
chassis) for optimum square corner at the start of the
holdoff portion (See Fig 11-2.7 ) of the sweep waveform.
Final adjustment will be made in Step 11.4.2.
2 OOv
. Scope under Test,10 psec/cm
Test Scope, 50 psec/cm
mplitude approx 155 v
B. Scope under
test,1 psec/cm
Test scope, 50
psec/cm. mpli
tude approx 160 v
C. Scope under test,
0.1 psec/cm. Test Scope,
5 psec/cm. mplitude
approx 190 v
Fig. 11-2.7 F ST SWEEP W VEFORMS
3-47
( Rpv i *f»H ^-62 3 C LIBR TION ND M INTEN NCE PROCEDURE

TIME/CM MULTIPLIER V RI - TIME M RKERS CORRECT COMPONENT (S)
Setti nq Setting BLE From 1
I80 DISPL Y Being checked
100 psec X 1 100 lisec 1 mark/cm C99C & D
100 psec X 2 100 lisec 2 marks/cm R99E & F
100 psec X 5 500 lisec 1 mark/cm R99D
100 psec 2.5-1 CW 100 lisec 1 mark/cm R99L
100 psec 2.5-1 CCW 500 lisec 5 (min) in 10 cm R99K, R99L
100 psec 5 - 2 CCW 500 lisec 10 (min) in 10 cm Swi tch
100 psec 12 - 5 CCW 1 msec 12 (min) in 10 cm Swi tch
Check for smooth Variable action in al1 ranges R99L
10 msec X 1 10 msec 1 ma rk/cm C99B
100 msec X 1 100 msec 1 mark/cm C99
1 sec X 1 1sec 1 mark/cm* R99C
1 sec X 2 1sec 2 marks/cm* R99B
1 sec X 5 5sec** 1 mark/cm* R99
*Pos i t i on base-line down <
off-screen to avoid burning phosphor while making measure-
ments at the 1, 2, 5 sec/cm sweep speeds.
**|f Type 1
180 is used, use 1 sec markers and check for 5 marks/cm.
T BLE 11-1
11.3.2 Troubleshooting:
11.3.2.1 One Calibrated Sweep Off: Check value of
component indicated in right-hand column.
11.3.2.2 Error Increases on Slowest Sweeps: Try replacing
V90, then V80 (possible leakage or gas). Check
for possible leakage across tube sockets, switch
wiring, etc. 500 meg ohms leakage will throw
5 sec/cm timing off by over 10%. Slow sweep
(1, 2, 5 sec/cm) timing can also be introduced
by emission from cathode to shield of V80. If
the V80 shield (pin 6) is grounded in your instru
ment, remove the ground connection, and connect
pin 6 (shield) to pin 2 or 7 (plate).
11.3.2.3 11 Sweeps Checked Show Constant Error: Recheck
11.1.4. If OK, measure R99F (can be measured
on switch if V90, & V80 removed) and C99C.
11.3.2.4 General: Check for correct voltages and wave
forms throughout timing circuits; try removing
V73; check for malfunction of V85 or neon bulb
B95. Recheck Horizontal mplifier; try Step
11.5.1 for severe waveform aberrations with
both sine and square-wave displays.
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3-49

13.2.2 5 psec/c Range; (Continued)
Log 1 c and 9 c dial readings for 10 psec/c and
2 psec/c sweeps. Difference between readings, as
before, ust be 8.00 ± 0.05, for each sweep rate.
13.2.3 Troubleshooting:
13.2.3.1 Excessive Ti ing Error: Exa ine Delaying Sweep display closely,
and see if direct display error corresponds to error indicated by
Helidial. If not, try replacing Delay Pickoff tubes, starting
with V I95, V I96 and V228. If error is confir ed^try tube
replace ent in Delaying Sweep generator, starting with V I90,
V I50, andV180. Ti ing co ponents are probably OK, unless
50 psec or 5 psec/c sweeps cannot be brought in with C190D
and Cl90F respectively.
13.2.3.1.1 Excessive Display Error, 2 usec/c : If 2 psec/c ti ing
is O.K. according to the Delay Ti e Multiplier and
* using the Main Sweep Delayed ode, but the Delaying
Sweep display itself indicates excessive error (± 2 to 4%),
C240 ay have been is-set (Step 11 .4.2.1). Try setting
C240 to correct the delaying sweep display error, then
repeat step 11.4, but without readjusting C240 again, if
possible. A co pro ise adjust ent ay be necessary
to keep both sweeps within display tolerance.
13.2.3.2 Excessive Sweep-Start Delay: Sweep-start delay involves Delay
Pickoff, Trigger-Gate and Main Sweep Gating Multivibrator
circuits as well as Delaying Sweep Trigger and Sweep circuits. It
is only partially co pensated for in the Main Sweep Delayed ode
by the vertical a plifier delay syste . Try changing oldest tubes
in these circuits first. If trigger-pickoff syste in vertical a plifier
is suspect, try triggering Delaying Sweep externally directly fro
180 (A). Recalibrate sections affected by tube changes before
proceeding. Failure of C197 (in V195 grid divider circuit) will
cause both non-linearity of fast sweeps and excessive "sweep
start delay". Failure of co pensating capacitor in any ulti
vibrator grid divider circuit will slow down action and add to delay.
13.3 LINEARITY CHECK: Check linearity at 50 psec/c and 5 psec/c as in 12.5.3.
Maxi u linearity error, 2 s all divisions on Helidial (.02). Log axi u error,
and point at which it occurs for each Sweep rate in Cal Record.
13.3.1 Troubleshooting: Linearity proble s ay be caused in either sweep generator
or delay pickoff circuits. Try replacing V I90, V I50 or V I80 in generator;
V I95, V I96 or V228 in pickoff circuit first. Check C197 (to grid of V I95)
and C l87 (to grid circuit, V150B) for possible open.
13.4 JITTER CHECK: Set up as for Pickoff Drift (Step 12.4.1), with Main Sweep Ti e/C
1000 ti es faster than Delaying Sweep. Adjust Delaying Sweep Stability and Triggering
Level controls for ini u jitter of Main Sweep Delayed display. Jitter at 1.00 c
delay should not exceed 2 ; at 9.00 c , 4 . Log actual jitter if within spec.
Otherwise, proceed with 13.4.1.
13.4.1 Troubleshooting: Try replacing Main Sweep and Delaying Sweep Holdoff tubes
7V54, V I50, V I40); re-check for excessive power-supply ripple. Try replace
ent of Delay Pickoff tubes. Repeat calibration sections involving any tubes
replaced. If tube replace ent fails to correct jitter, check R195, R208 and R209
for excessive noise; try replacing V37, V43, V190, V180, V155, and/or
Delaying Sweep trigger tubes.
(Revised 5-62) C LIBR TION ND M INTEN NCE PROCEDURE 3-61

15.6 TROUBLESHOOTING; Most common malfunctions and aberrations in the vertical .
amplifier circuitry will have been cleaned up by tube and component replace
ments in Steps 7 and 15.1. Listed below are some of the unusual and in
frequent failures causing effects only noticeable during fast-rise obser
vations.
15.6.1 Risetime Too Slow for Correction by djustment: Open suppressor
bypass capacitor(s) in distributed amplifier. Open compensating
capacitor across 47 or 33 ohm series resistor in cathode of driver
stage. Increase in plate-load resistor in input amplifier stage.
Change in input or D stage cathode or screen resistors. Possibly
open 0.68 pf “speedup1' (series) capacitors in delay line.
15.6.2. Excessive Spiking. More than 30 me “Bandwidth1.1: Open Capacitor in
plate 1i ne.
NOTE: Be sure that “spiking" is not overshoot due
to cathode interface (See Step 7.1.3 and Fig 7-4).
In instruments below S/N 9292, try removing slugs
from LI041 and L1022: These may have been added
in error.
15.6.3 Excessive “Termination Bump": Failure of the fixed or variable
capacitors or heat damage to R L components in the termination
network wi 11 cause uncorrectable wrinkle about 1/2 psec from the
leading edge. Replace any out-of tolerance or damaged components.
15.6.4 Oscillations, Severe Single-Frequency Ringing: Check for open by
pass capacitor, particularly on filament line or at plate of CF.
Failure of 150 pf inter-cathode coupling capacitors in D may
cause oscillations in the 100-200 me range. Be sure that the
(white) trigger pickoff lead is dressed away from signal circuits
near the 16 pin interconnecting socket.
NOTE: Certain instruments in the serial range 10,000
to 13,000 tend to oscillate when used with some Type
53/54C and C plug-ins, sometimes only at extreme positions
of the vertical position control. Check the location
of Cl 054, the .005 bypass disc capacitor from the D
common plate supply to ground. If this is located at
pin 5 of VI054, remove it and instal1 it between the
load end of Rl054 (167 fi, 5 watt) and the ground lug
on C1005 adjacent to this terminal. This should eliminate
the oscillations. In some cases (S/N 9292-up) a .01 pf
600 v discap from the B+ end of LI064 to the ground lug
on the adjacent 12BY7 socket elimi nates the prob1em
completely.
15.6.5 Miscellaneous bberations Not Correctable by djustment: Possible
failure of components in RC balancing networks in delay line.
15.6.6 Step Waveform Tilts Downward to the Left: If the first 1/2 psec
of the waveform tilts downward to the left, giving the appearance
of serious “undershoot" at about 5 psec/cm, it may be due to
defective D. . tubes. (Figure 7-5). Try a new set of tubes.
(Revised 5“62) C LIBR TION ND M INTEN NCE PROCEDURE 3-72