Tenma 72-6802 User manual


30MHz Dual Trace Oscilloscope
Model 72-6802
USER MANUAL

This manual contains proprietary information, which is protected by copyrights. All rights
are reserved. No part of this manual may be photocopied, reproduced or translated to
another language without prior written consent of Tenma Test Equipment.
The information in this manual was correct at the time of printing. However, Tenma
continues to improve products and reserves the rights to change specification, equipment,
and maintenance procedures at any time without notice.
Tenma Test Equipment
405 S. Pioneer Blvd. Springboro Ohio, 45036

TABLE OF CONTENTS
3
Table of Contents
SAFETY INSTRUCTIONS ................................................................................5
PRODUCT OVERVIEW .................................................................................. 10
Product Description .....................................................10
Main Features.................................................................11
Block Diagram ...............................................................12
PANEL OVERVIEW ....................................................................................... 13
Front Panel Overview ...................................................13
Display Controls............................................................14
LCD Display....................................................................15
Horizontal Controls ......................................................16
Vertical Controls ..........................................................17
Trigger Controls ...........................................................19
Input Terminals ............................................................22
Rear Panel Overview ...................................................23
SETUP .........................................................................................................24
Default Settings ...........................................................24
Set up & Probe Compensation....................................26
MEASUREMENT........................................................................................... 28
Single Channel (Basic) Measurement ........................28
Dual Channel Measurement.........................................30
Waveform Addition/Subtraction ................................32
Frequency Measurement.............................................32
X-Y Mode .......................................................................33
Waveform Magnification..............................................34
FAQ ............................................................................................................ 35
72-6802 User Manual
APPENDIX ...................................................................................................37
Line Voltage & Fuse Replacement .............................. 37
Specifications ..............................................................39
Declaration of Conformity........................................... 41

SAFETY INSTRUCTIONS
5
SAFETY INSTRUCTIONS
Thischaptercontainsimportantsafetyinstructions
thatyoumustfollowwhenoperatingandstoring
thisinstrument.Readthefollowinginstructions
beforeoperatingtheinstrumenttoensureyour
safetyandtokeepitinbestcondition.
Safety symbols
Thesesafetysymbolsmayappearinthismanualoronthe
instrument.
WARNING Warning:Identifiesconditionsorpracticesthat
couldresultininjuryorlossoflife.
CAUTION Caution:Identifiesconditionsorpracticesthat
couldresultindamagetotheinstrumentorto
otherproperties.
DANGER:HighVoltage
Attention:RefertotheManual
ProtectiveConductorTerminal
Earth(Ground)Terminal
72-6802 User Manual
6
Safety guidelines
General
Guideline
CAUTION
•Neverconnectahazardouslivevoltagetothe
groundsideoftheBNCconnectors.Itmight
leadtofireorelectricshock.
•Donotplaceheavyobjectsontheinstrument.
•Avoidsevereimpactsorroughhandlingsthat
leadtodamagingtheinstruments.
•Donotdischargestaticelectricityontothe
instruments.
•Useonlymatingconnectors,notbarewires,for
theterminals.
•Donotblockthecoolingfanopening.
•Donotperformmeasurementsatpower
generatingsourcesandbuildinginstallation
sites(Seenotebelow).
•Donotdisassembletheinstrumentunlessyou
aretechnicallyqualified.
•TopreventapermanentdamagetotheCRT
phosphor,avoidexcessivelybrighteningthe
traceorholdingalightspotforanunreasonably
longtime.
•Donotoperatetheinstrumentinaplacewhere
strongmagneticorelectricfieldexistsasitmay
disturbthemeasurement.
•Makesuretheinputvoltagedoesnotexceedthe
followingvalues.
Input Terminal Maximum Input Voltage
CH1,CH2input300Vpeak
EXTTRIGinput300Vpeak

SAFETY INSTRUCTIONS
7
Probeinput600Vpeak
ZAXISinput30Vpeak
(Measurement categories) EN 61010-1:2001 specifies the measurement categories and
their requirements as follows. The 72-6802 falls under category II.
•Measurement category IV is for measurements performed at the source of low-
voltage installations.
•Measurement category III is for measurements performed in building installations.
•Measurement category II is for measurements performed on the circuits directly
connected to low voltage installations.
•Measurement category I is for measurements performed on circuits not directly
connected to mains.
Power Supply
WARNING
•ACInputvoltage:115V/230VAC,50/60Hz
•Thepowersupplyvoltageshouldnotfluctuate
morethan15%.
•Toavoidelectricshock,connecttheprotective
groundingconductoroftheACpowercordto
anearthground.
Fuse
WARNING
•Fusetype:T0.63A/250V(AC115V),
T0.315A/250V(AC230V)
•Makesurethecorrecttypeoffuseisinstalled
beforepowerup.
•Toensurefireprotection,replacethefuseonly
withthespecifiedtypeandrating.
•Disconnectthepowercordbeforefuse
replacement.
•Makesurethecauseoffuseblowoutisfixed
beforereplacingthefuse.
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8
Cleaning the
instrument
•Disconnectthepowercordbeforecleaningthe
instrument.
•Useasoftclothdampenedinasolutionofmild
detergentandwater.Donotsprayanyliquid
intotheinstrument.
•Donotusechemicalscontainingharshproducts
suchasbenzene,toluene,xylene,andacetone.
Operation
Environment
•Location:Indoor,nodirectsunlight,dustfree,
almostnon‐conductivepollution(Seenote
below)
•RelativeHumidity:<85%,non‐condensing
•Altitude:<2000m
•Temperature:0°Cto40°C
(Pollution Degree) EN 61010-1:2001 specifies the pollution degrees and their requirements
as follows. The 72-6802 falls under degree 2.
Pollution refers to “addition of foreign matter, solid, liquid, or gaseous (ionized gases),
that may produce a reduction of dielectric strength or surface resistivity”.
•Pollution degree 1: No pollution or only dry, non-conductive pollution occurs. The
pollution has no influence.
•Pollution degree 2: Normally only non-conductive pollution occurs. Occasionally,
however, a temporary conductivity caused by condensation must be expected.
•Pollution degree 3: Conductive pollution occurs, or dry, non-conductive pollution
occurs which becomes conductive due to condensation which is expected. In such
conditions, equipment is normally protected against exposure to direct sunlight,
precipitation, and full wind pressure, but neither temperature nor humidity is
controlled.
Storage
environment
•Location:Indoor
•RelativeHumidity:<70%
•Temperature:–10°Cto70°C

SAFETY INSTRUCTIONS
9
Power cord for the United Kingdom
WhenusingtheinstrumentintheUnitedKingdom,makesurethe
powercordmeetsthefollowingsafetyinstructions.
NOTE: This lead/appliance must only be wired by competent persons
WARNING: THIS APPLIANCE MUST BE EARTHED
IMPORTANT: The wires in this lead are coloured in accordance with the
following code:
Green/ Yellow: Earth
Blue: Neutral
Brown: Live (Phase)
As the colours of the wires in mains leads may not correspond with the
colours marking identified in your plug/appliance, proceed as follows:
The wire which is coloured Green & Yellow must be connected to the Earth
terminal marked with the letter E or by the earth symbol or coloured Green
or Green & Yellow.
The wire which is coloured Blue must be connected to the terminal which is
marked with the letter N or coloured Blue or Black.
The wire which is coloured Brown must be connected to the terminal marked
with the letter L or P or coloured Brown or Red.
If in doubt, consult the instructions provided with the equipment or contact
the supplier.
This cable/appliance should be protected by a suitably rated and approved
HBC mains fuse: refer to the rating information on the equipment and/or user
instructions for details. As a guide, cable of 0.75mm2should be protected by
a 3A or 5A fuse. Larger conductors would normally require 13A types,
depending on the connection method used.
Any moulded mains connector that requires removal /replacement must be
destroyed by removal of any fuse & fuse carrier and disposed of immediately,
as a plug with bared wires is hazardous if a engaged in live socket. Any re-
wiring must be carried out in accordance with the information detailed on this
label.
72-6802 User Manual
10
PRODUCT OVERVIEW
Product Description
TheTenmaModel72‐6802oscilloscopeisaportable,dual‐channel
oscilloscope.Itprovidesmaximum30MHzDCbandwidthand
1mV/DIVsensitivity.Itstimebasereaches0.2μS/DIVandthesweep
speed100nS/DIV.The72‐6802usesa6‐inchrectangularcathoderay
tubedisplaywithredinternalgraticule.Thisisasturdy,easy‐to‐
operate,andhighlyreliabileproduct.The72‐6802alsoincorporates
aseparateLCDDisplay,whichcanshowCH1/CH2VOLT/DIV,
TIME/DIV,X‐YMODE,andFrequency.

PRODUCT OVERVIEW
11
Main Features
High intensity
and
acceleration
CRT
TheCRTincorporateshighbeamtransmission,
highintensity,anda2kVhighaccelerationvoltage.
TheCRTdisplaysclearlyreadabletracesevenat
highersweepspeeds.
Wide
bandwidth and
sensitivity
InadditiontotheDC‐30MHz(‐3dB)wide
bandwidth,theoscilloscopeprovidesa1mV/DIV
highsensitivity.The30MHzfrequencyrangeis
obtainedbyanimprovedtriggering
synchronization.
Frequency
Counter
Abuilt‐in5‐digitfrequencycounteroffers±0.02%
accuracybetween1kHzand30MHz,and±0.05%
between50Hzand1kHz.
Automatic
timebase
adjustment
PressingtheAUTOTIMEBASEkeyautomatically
adjuststhesweeptimetoanappropriaterange.
Alternate
triggering
Evenwhenobservingtwowaveformsindifferent
frequencies,bothwaveformscanbestably
triggeredusingthealternatetriggeringmode.
TV sync
triggering:
Theoscilloscopehasasyncseparatorcircuitfor
theTV‐VandTV‐Hsignaltriggering.
CH1 output TheCH1signalisoutputfromarearpanel
terminal,whichcanbeappliedtoexternaldevices.
Z-axis input DisplayintensitycanbecontrolledviatheTTL
compatiblez‐axisinputontherearpanel.
X-Y mode TheX‐YmodecomparestheCH1andCH2signal
amplitude.Itisusefulforcomparingthephase
difference.
Buzzer alarm Incorrectoperationgeneratesawarningbeep.
72-6802 User Manual
12
Block Diagram

PANEL OVERVIEW
13
PANEL OVERVIEW
Front Panel Overview
Detaileddescriptionsofeachblockstartfromthenextpage.
Main Display Showsthewaveformsofinputsignals.
Display
Controls
Controlspoweron/off,displayconfiguration,and
theprobecompensationoutput.
LCD Display Showstheverticalscale,horizontalscale,X‐Y
displaymode,andwaveformfrequencies.
Horizontal
Controls
Controlsthehorizontalscale,horizontalposition,
sweeplength,andx10magnification.
Vertical
Controls
Controlstheverticalscale,verticalposition,display
mode,CH2inversion,andalternatedisplaymode.
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14
Trigger
Controls
Controlsthetriggermode,triggerlevel,trigger
couplingsource,triggerslope,andalternate
triggeringmode.Acceptstheexternaltriggerinput.
Input
Terminals
AcceptstheCH1andCH2inputsignalsandground
wire.Controlstheinputsignalcouplingmode.
Display Controls
654321
1 CAL Output Generatestheprobecompensationsignal;2Vp‐p,
1kHz,positivesquarewave.Forprobe
compensationdetails,seepage26.
2 INTEN Knob Controlsthebrightnessofalightspotortracein
thedisplay.
3 FOCUS
Knob
Controlsthefocus(sharpness)ofthewaveformsin
thedisplay.
4 TRACE
ROTATION
Point
Controlsthealignmentofthehorizontaltracein
parallelwithgraticulelines.
5 AUTO
TIMEBASE
Key
Automaticallyadjuststhehorizontalscaletoan
appropriaterangeaccordingtotheinputsignal.
6 POWER
Switch
Turnsonorofftheoscilloscope’smainpower.
Whenthepowerison,theLEDlights.

PANEL OVERVIEW
15
LCD Display
1 CH1
Vertical
Scale
ShowstheCH1verticalscale.
2 Horizontal
Scale
Showsthehorizontalscale.
3 X-Y Mode Whenturnedon,indicatesthattheX‐Ymodeis
activated.ForX‐Ymodedetails,seepage33.
4 Signal
Frequency
Showsthewaveformfrequency.Forfrequency
measurementdetails,seepage32.
5 CH2
Vertical
Scale
ShowstheCH2verticalscale.
72-6802 User Manual
16
Horizontal Controls
1 Horizontal
POSITION
Knob
Controlsthehorizontalpositionoftracesandlight
spots.
2 ×10 MAG
Switch
Magnifiesthehorizontalscalebyafactorof10.For
horizontalmagnificationdetails,seepage34.
3 SWP VAR
Knob
Adjuststhehorizontalscale.
Attheminimumposition,thehorizontalscale
becomes2.5timeswiderthantheoriginalvalue
selectedbytheTIME/DIVknob.Forexample,ifthe
originalscaleis1mS/DIV,theadjustedscale
becomes2.5mS/DIV.
Atthemaximum(CAL)position,thereisno
changeinthehorizontalscale.
4 TIME/DIV
Knob
Controlsthehorizontalscalefrom0.2μs/divto0.5
s/divin20steps.
When“X‐Y”isselected,theoscilloscopeworksin
theX‐Ymode.ForX‐Ymodedetails,seepage33.

PANEL OVERVIEW
17
Vertical Controls
1 VOLTS/DIV
Knob
ControlstheCH1/CH2verticalscalefrom
1mV/DIVto5V/DIVin12steps.
2 Vertical
POSITION
Knob
Controlstheverticalpositionoftracesandlight
spotsforCH1/CH2.
3 ALT/CHOP
Switch
SelectshowtheCH1andCH2signalsappear inthe
display,intheDUALtracemode.
CHOP
Thetwosignalsarechoppedand
displayedsimultaneously(generally
usedinslowsweep,1ms/DIVor
slower).
ALT
Thetwosignalsaredisplayed
alternatively(generallyusedinfast
sweep,0.5ms/DIVorfaster).
4 Vertical
MODE
Switch
SelectsCH1andCH2displaymodes.
CH1/CH2TheCH1orCH2signalisdisplayed
independently.
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DUALTheCH1andCH2signalsaredisplayed
simultaneously.
ADDTheCH1andCH2signalsareaddedor
subtracted,andthentheresultis
displayed.ForCH1/CH2
addition/subtractiondetails,seepage32.
5 VAR Knob Adjuststheverticalscale.
Attheminimumposition,theverticalscale
becomes2.5timeswiderthantheoriginalvalue
selectedbytheVOLTS/DIVknob.Forexample,if
theoriginalscaleis1mV/DIV,theadjustedscale
becomes2.5mV/DIV.
Atthemaximum(CAL)position,thereisno
changeintheverticalscale.
6 CH2 INV
Switch
InvertstheCH2inputsignalvertically.Whenthe
verticalmodeswitchisintheADDposition,CH2is
subtractedfromCH1insteadofbeingaddedto
CH1.ForCH1/CH2addition/subtractiondetails,
seepage32.

PANEL OVERVIEW
19
Trigger Controls
1 Trigger ALT
Switch
Whenpressed,theTRIGALTswitchconstantly
togglesthetriggersourcebetweenCH1andCH2
signal,sothatbothsignalscanbeclearlyviewed.
TheTRIGALTswitchworkswhenthevertical
modeisintheDUALpositionandalsothetrigger
sourceisintheCH1orCH2position.
Note
•TheTRIGALTswitchdoesnotworkwhenthe
ALT/CHOPswitchisintheCHOPposition.
•ThefrequencycounterintheLCDdisplaydoes
notworkwhentheTRIGALTswitchispressed.
2 Trigger
MODE
Switch
TheTRIGGERMODEswitchselectswhenthe
oscilloscoperespondstothetriggerconditions.
AUTO Theoscilloscopesweepsregardlessof
theexistenceoftriggerconditions.
NORM Theoscilloscopesweepsonlywhena
triggerconditionoccurs.
72-6802 User Manual
20
TV-V Theoscilloscopetriggerswhena
verticalvideosynchronizationsignal
appears.Fortriggeringonthefield,
select2ms/DIVasthehorizontalscale;
fortriggeringontheframe(two
interlacedfields),5ms/DIV.
TV-H Theoscilloscopetriggerswhena
horizontalvideosynchronization
signalappears.Fortriggeringonthe
line,select10us/DIVasthehorizontal
scale.UsetheSWPVARknobto
controlthenumberofwaveforms.
Note
•ForTV‐VandTV‐Htrigger,the
oscilloscoperespondsonlyto
negativepolaritysignals.

•Theoscilloscopecannottrigger
inputsignalswhentheir
frequenciesarelessthan25Hz.
3 Trigger
LEVEL Knob
Changesthetriggerlevelvertically.
ThetriggerlevelmovesupwhenthetriggerLEVEL
knobisturnedclockwise.
Thetriggerlevelmovesdownwhenthetrigger
LEVELknobisturnedcounterclockwise.

PANEL OVERVIEW
21
4 Trigger
SLOPE
Switch
Selectsthetriggeringslope.
Wheninthe“+”position(),theoscilloscope
triggerswhenthepositiveslopeofthetrigger
sourcesignalcrossesthetriggerlevel.
Wheninthe“–”position(),theoscilloscope
triggerswhenthenegativeslopeofthetrigger
sourcesignalcrossesthetriggerlevel.

5 Trigger
SOURCE
Switch
Selectsthesignalonwhichtheoscilloscopesweeps.
CH1CH1signalbecomesthetrigger
source.
CH2CH2signalbecomesthetrigger
source.
LINEACpowerlinesignalbecomesthe
triggersource.Usefulwhentheinput
signalsynchronizeswiththepower
linefrequency.
EXTTheexternaltriggerinput(TRIGIN
terminal)signalbecomesthetrigger
source.
6 TRIG IN
Terminal
Acceptsanexternaltriggersourcesignal.The
signalbecomesactivewhenthetriggerSOURCE
switchisintheEXTposition.
Inputimpedance:1MΩ//25pF
72-6802 User Manual
22
Input Terminals
1 CH 1 (X)
Input
Terminal
AcceptstheCH1inputsignal.InX‐Ymode,the
CH1inputsignalbecomestheX‐axis.
2 AC/GND/
DC Switch
Selectsthecouplingmodefortheinputsignal.
AC TheoscilloscopeblockDCcomponents
includedintheinputsignal.
GND Showstheground(zerovolt)levelon
thedisplay.Thismodeisonlyfor
checkingthereferencelevel;input
signaldoesnotappearonthedisplay.
DC Theoscilloscopedisplaysallofthe
inputsignal.
3 GND
Terminal
Acceptsagroundwire.TheGNDterminalis
connectedtotheoscilloscopemainframe.
4 CH 2 (Y)
Input
Terminal
AcceptstheCH2inputsignal.InX‐Ymode,the
CH2inputsignalbecomestheY‐axis.
•ForX‐Ymodedetails,seepage33.

PANEL OVERVIEW
23
Rear Panel Overview
1 FUSE & Line
Voltage
Selector
HoldstheACmainsfuseandselectstheACline
voltage,115Vor230V.
2 AC Power
Input
Connector
AcceptstheACpowercord.
3 CH1
OUTPUT
Terminal
OutputstheCH1signal;approximately20mV/DIV
whenterminatedwith50Ω.
4 Z AXIS
INPUT
Terminal
Acceptsanexternalintensitymodulation(Z‐axis)
signal;1kHzsquarewave,DC–2MHz.Positive
goingreducesintensity.Fordetailedspecifications,
seepage39.
•ForAClinevoltageselectionandfusereplacement,seepage37.
72-6802 User Manual
24
SETUP
Default Settings
Beforepoweringuptheoscilloscope,setupthefrontpanelas
follows.
POWER Switch
Off
INTEN Knob
Center
FOCUS Knob
Center
Vertical MODE
Switch
CH1
ALT/CHOP
Switch ALT()
CH 2 INV
Switch
Released(Inversiondisabled)
CH1/CH2
Vertical
POSITION
Knob
Centerofthedisplay
CH1/CH2
VOLTS/DIV
Knob
50mV/DIV

SETUP
25
CH1/CH2
VARIABLE
Knob
CAL
CH1/CH2
Coupling
Switch
AC
Trigger
SOURCE Switch
CH1
Trigger SLOPE
Switch
+(Positiveslope)
TRIG ALT
Switch
Released(alternatingtrigger
disabled)
Trigger MODE
Switch
AUTO
TIME/DIV
Knob
0.5ms/DIV
Horizontal
SWP.VAR Knob
CAL
Horizontal
POSITION
Knob
Centerofthedisplay
x10 MAG
Switch
Released(x10maginification
disabled)
72-6802 User Manual
26
Set up & Probe Compensation
Followthesestepsandproperlysetuptheoscilloscope,makesureit
isfunctional,andcompensatetheprobe.
1 Power on PressthePowerswitchandturn
ontheoscilloscope’spower.The
LEDlightswhenthepowerison.
Thetracelinestartstoappearafter
20–30seconds.
2 Intensity
and focus
adjustment
UsetheINTENknobandFOCUS
knobtoadjustthetraceline
appearancetothebestcondition.
3 Probe
connection
Connecttheprobebetweenthe
CALoutputandtheCH1input
terminal.Selectx10(attenuation)
ontheprobe.
Selectx10(attenuation)ontheprobe.
4 Probe
attenuation
x1
0
x1
5 Coupling
mode
selection
SelecttheACpositionintheCH1
AC‐DC‐GNDswitch.Asquare
waveformappearsinthedisplay.

SETUP
27
6 Vertical
adjustment
UsetheCH1VOLTS/DIVknob
andCH1verticalPOSITIONknob
toadjusttheverticalscaleand
positionofthewaveform.
7 Horizontal
adjustment
UsetheCH1TIME/DIVknoband
CH1horizontalPOSITIONknobto
adjustthehorizontalscaleand
positionofthewaveform.
Adjustthecompensationpointontheprobeso
thatthewaveformbecomessquare.
8 Probe
compensa-
tion
Under compensation Right amount Over compensation
9 Completion
Nowsettinguptheoscilloscopeiscompleted.For
moreadvancedmeasurements,seepage28.
72-6802 User Manual
28
MEASUREMENT
Single Channel (Basic) Measurement
Steps 1. Connecttheinputsignaltothe
CH1orCH2terminal.
2. Selecttheverticalcoupling
betweenAC(DCcomponents
areblocked)orDC(allsignal
componentsappear).
3. Configurethetriggersettings.
Fordetails,seepage19.
4. UsetheVOLTS/DIVknoband
verticalPOSITIONknobto
adjusttheverticalscaleand
positionofthewaveform.
5. PresstheAUTOTIMEBASE
keytoautomaticallyadjustthe
horizontalscaleaccordingto
theinputsignal.

MEASUREMENT
29
6. Ifnecessary,usetheTIME/DIV
knobtoadjustthehorizontal
scalemanually.Usethe
horizontalPOSITIONknobto
adjustthepositionofthe
waveform.
72-6802 User Manual
30
Dual Channel Measurement
Steps 1. ConnectbothCH1andCH2
signalstotheinputterminals.
2. Selecttheverticalcoupling
betweenAC(DCcomponents
areblocked)orDC(allsignal
componentsappear)forboth
channels.
3. Configurethetriggersettings.
Fordetails,seepage19.
MakesurethetriggerSOURCE
switchisineithertheCH1or
CH2position.
4. SettheverticalMODEswitchto
theDUALposition.
5. BoththeCH1andCH2signalsappearonthe
display.

MEASUREMENT
31
6. UsetheverticalALT/CHOP
switchtoselecthowthetwo
waveformappearonthe
display:alternately(ALTmode)
orsimultanouesly(CHOP
mode).Seepage17fordetails.
7. Ifnecessary,usethe
VOLTS/DIVknobandvertical
POSITIONknobtoadjustthe
verticalscaleandpositionof
thewaveform.
8. Ifnecessary,usetheTIME/DIV
knobandhorizontalPOSITION
knobtoadjustthehorizontal
scaleandpositionofthe
waveform.
Note
ThetriggerALTswitchdoesnot
workwhentheALT/CHOPswitch
isintheCHOPposition.
72-6802 User Manual
32
Waveform Addition/Subtraction
Steps 1. MakesurebothCH1andCH2
waveformsappearonthe
display.Fordetails,seepage30.
2. SettheverticalMODEswitchto
theADDposition.Thetwo
waveformsareaddedand
appearonthedisplayasa
singlewaveform.
3. TosubtracttheCH2signalfrom
theCH1signal,inverttheCH2
signalbypressingtheCH2INV
switch.
Frequency Measurement
Frequency
shown on the
LCD
Thefrequencyoftheinputsignalappearsonthe
LCDdisplayandisconstantlyupdated.

Frequency
measurement
using the CH1
output
TheCH1signalfrequencycanbe
measuredusinganexternaldevice
suchasfrequencycounter,viathe
rearpanelterminal.

MEASUREMENT
33
X-Y Mode
Background TheX‐Ymodecomparestheamplitudeoftwo
signals(CH1andCH2),oneasX‐axis(CH1)and
theotherasY‐axis(CH2).TheX‐Ymodeisuseful
formeasuringthephasedifferenceoftwosignals,
videocolorpatterns,andfrequencyresponse.
Steps 1. MakesurebothCH1andCH2
waveformsappearonthe
display.Fordetails,seepage30.
2. MovetheTIME/DIVknobtothe
X‐Yposition.
3. TheCH1andCH2signalsappearintheX‐Y
modeandtheX‐YindicatorintheLCDdisplay
(X‐Y)turnson.
4. ToadjusttheX‐axispositionand
deflection,usethehorizontal
POSITIONknob(position)and
CH1VOLTS/DIVknob
(deflection).
72-6802 User Manual
34
5. ToadjusttheY‐axispositionand
deflection,usetheCH2vertical
POSITIONknob(position)and
CH2VOLTS/DIVknob
(deflection).
Waveform Magnification
Background Theoscilloscopecanmagnifythewaveformbyten
timesinthehorizontaldirection.The
magnificationisusefulforobservingcomplex
signals.
Steps 1. Makesurethewaveformisshownonthe
display.
2. Pressthe×10MAGswitch.The
waveformbecomesmagnified
bytentimesinthehorizontal
direction.
x10 magnification
Any part can be covered by using the POSITION control

FAQ
35
FAQ
The probe waveform is distorted.
Youmightneedtocompensatetheprobe.Fordetails,seepage26.
Notethatfrequencyaccuracyanddutyfactorarenotspecifiedfor
theprobecompensationwaveformandthereforeitshouldnotbe
usedforreferencepurpose.
The trace line does not appear on the display.
MakesurethatthetriggermodeisintheAUTOmode.Inthe
NORMALmode,thetracedoesnotappearunlessatrigger
conditionoccurs.
The alternate trigger (TRIG ALT switch) does not work.
MakesurethattheALT/CHOPswitchisreleased(ALTposition).
TheTRIGALTswitchdoesnotworkintheCHOPmode.
The frequency counter in the LCD display does not work.
MakesurethattheTRIGALTswitchisnotpressed.Thefrequency
counterdoesnotworkinthealternatetriggermode.
The TV trigger does not work.
Makesurethatthevideosynchronizationsignalispositive.TheTV‐
V/TV‐Htriggerworksonlywhenthesynchronizationsignalis
negative.
72-6802 User Manual
36
The input signal does not appear on the display.
Checkthefollowingsettings.
•ThecouplingmodeisnotsetattheGNDmode,inwhichthe
waveformdoesnotappearonthedisplay.Seepage22fordetails.
•Theappropriatetriggersourceisselected.Seepage19fordetails.
The oscilloscope accuracy does not match the specifications.
Makesuretheoscilloscopeispoweredonforatleast30minutes,
within+20°C–+30°C.Thisisnecessarytostabilizetheoscilloscope.
Formoreinformation,contactyourlocaldealer,Tenmawebsite
www.tenma.com.,orMCMElectronicsatwww.mcmelectronics.com.

APPENDIX
37
APPENDIX
Line Voltage & Fuse Replacement
1. Takeoffthepowercord.
115
230
2. Useasmallminusdriverandpulloutthefusesocket.
115
230
3. Rotatetheholdersothatthetargetvoltagemarkingmovestothe
upperside.
115
230
AC115V
230
115
AC230V
115
230
72-6802 User Manual
38
4. Ifnecessary,replacethefusethatisattachedtothefuseholder.
115
230
5. Pushthefuseholderbackintothesocket.
230
115
Fuse rating AC115V:T0.63A/250V,AC230V:T0.315A/250V

APPENDIX
39
Specifications
Thespecificationsapplywhenthe72‐6802ispoweredonforatleast
30minutesunder+20°C–+30°C.
Vertical Sensitivity accuracy 1mV/DIV to 2mV/DIV: ±5%
5mV/DIV to 5V/DIV: ±3%
Bandwidth 1mV/DIV to 2mV/DIV: DC to 7MHz
5mV/DIV to 5V/DIV: DC to 30MHz
AC coupling > 10Hz (reference: 100kHz, 8DIV, –3dB)
Rise time 1mV/DIV to 2mV/DIV: Approx. 50nS
5mV/DIV to 5V/DIV: Approx. 11.7nS
Input impedance Approx. 1M ohm // 25pF.
Square wave
characteristics
≤5% Overshoot at 10mV/DIV
Other ranges: 5% added to the above
Linearity ±0.1DIV when moving 2 DIV at center
Vertical mode CH1, CH2, DUAL, ADD
Chop frequency Approx. 250kHz
Input coupling AC, GND, DC
Max input voltage CAT II 300Vpeak (AC: ≤1kHz)
Max effective
readout
Probe1:1 40Vpp (14Vrms Sine wave)
Probe10:1 400Vpp (140Vrms Sine wave)
Common mode
rejection ratio
≥50:1 at 50kHz sine wave
(CH1 and CH2 vertical scales are equal)
Channel isolation @
5mV/DIV
>1000:1 at 50kHz
>30:1 at 30MHz
CH1 signal output ≥20 mV/DIV @ 50Ω,50Hz to 5MHz
CH2 INV BAL. ≤1 DIV (Reference at center graticule)
Trigger Trigger source CH1, CH2, LINE, EXT
Coupling AC: 20Hz to full bandwidth
Slope + / -
Sensitivity 20Hz to 2MHz : 0.5 DIV
(TRIG-ALT:2 DIV, EXT: 200mV)
2MHz to 30MHz: 1.5 DIV
(TRIG-ALT:3 DIV, EXT: 800mV)
TV: Sync pulse > 1 DIV (EXT: 1V)
Triggering modes AUTO, NORM, TV-V, TV-H
EXT TRIG input Input impedance: Approx.:1MΩ// 25pF
Max. input: CAT II 300Vpeak < 1kHz
72-6802 User Manual
40
Horizontal Axis Sweep time accuracy 0.2µS to 0.5S/DIV, ±3%
x10MAG accuracy
±5% (20/50nS uncalibrated)
Linearity ±3%, x10:±5% (20/50nS uncalibrated)
X-Y Mode Sensitivity Same as vertical axis
Bandwidth DC to at least 500kHz
Phase Difference
≤3 degrees at DC to 50kHz
Z-Axis Sensitivity 5Vpp (Positive going reduces intensity)
Bandwidth DC to 2MHz
Input resistance Approx. 47kΩ
Max input voltage CAT II 30Vpeak (AC ≤1kHz)
Waveform Positive-going square wave
Frequency Approx. 1 kHz
Duty Ratio Within 48:52
Output voltage 2 Vp-p ±2%.
Probe
Compensation
Signal
Output impedance Approx. 1 kΩ
Display Digits Maximum 5 digit decimal
Frequency
Counter Frequency Range 50Hz to 30MHz
Accuracy
50Hz to 1kHz: ±0.05%
1kHz to 30MHz: ±0.02%
Sensitivity > 2DIV
LCD Display VOLT/DIV, TIME/DIV, X-Y, Frequency
Backlight Orange
CRT Type 6-inch rectangular, internal graticule
Phosphor P 31
Acceleration Volt. Approx. 2kV
Screen Size 8 ×10 DIV (1 DIV = 10mm (0.39in))
Power Source AC115V/230V±15%, 50/60Hz
Power Approx. 40VA, 35W(max.)
Operation
Environment
Indoor use, Altitude ≤2000 m
Ambient temperature :
To satisfy specifications:10℃to 35℃(50°F to 95°F)
Maximum operating range: 0℃to 40℃(32°F to 104°F)
Relative humidity: 85% RH(max.) non-condensing
Installation Category II, Pollution degree 2
Storage
Environment
Ambient temperature: -10℃to 70℃
Relative humidity: 70%RH (maximum)
Accessories Power cord x 1, User manual x 1, Probe x 2
Dimensions 310 (W) x 150 (H) x 455 (D) mm
Weight Approx.8.2kgs (18.0lbs)