Mastech M840D User manual

1. r
This Digrtal MuKirneter is a compact Pfusion, battery operated' LCD
display */r*r^+% digib DEital lnstrument"
Hrgh ffiq.Iracy
lcon disPl aY {3}/, onlY)
Digitalheight 22mm
Siñgt¿ sg"position *t*ny swttclr for FUNCTION and RANGE
iet&tion, allor¡rs fast and convenient operation
SuperiaritY:
.l
"/
',/ /
{
2J
3)
4)
5)
I Curvilinear mde $ofl ca$e ¿,-- 1-^r,^^^ra
t tolüred indicaüon iack with fulty protecfion test leads'
./ Lower overage PowerAutoPower Off
2. GENERAL SFECIFI_GATION
1) Display }% digis Iq?*m a maximurn reading o1 1999:DTffi0r
& M10ffi is+úJÉrs lCp wiür a maximum rcading of 19999'
Measursment rate: uPdates ?3/sec'
Ou*ii*nge indication: "1" figure only in flre display
Automatic negative planty indication'
Tü "#3'; ¡* Ci*pf"y-d *tten fie battery voltage drops below the
operating voltage-
6) Futlt*g* aúer bad Protedion"
Vi c;p".f,ánte mea$urelnentAut+Zeroip
s)AutoPowsrotr:ltwillbeautomati@llyctJtoffinaboutlSminutes
afier üTe porruer li turned on. ti neds to be tt¡rned off and tt¡med on
again to iontinue the pouÉf' ^ ¡^^^ ^ ,rnt e
9) *Oper*ting ternprature:9'9-40"C' ry5f R H
' SoÉge tet*pe'"aiure : - t O" C¡ 5S'C, 0*75olo R H'
10) Power: $ingl* standq$-?.lb"tt*'y IEC 6F22,NEDA 1604, Jls 006P'
tti nimensioná: 176l*88$f38Hrnm'
12i Weight approx 310g (including batteryi
1l) Acces$o¡ü: te*t r*ád* @iti,;ptq ú,e 0"5A piece in case (model
. MB40D n¡se zni K-type tile*itffiuple wire (model M890C*/M890G
onlyi, oPer:ation manual. ¡--.^r:dñ
s.- Éi ,
Am'racy ¡s giuenlJitt-_ói@iig i number of reast significant digib
forone úeár,át 23"ct5"c RH<75%
1) DüV

l?/\¡i{iü AtjCi.lR:1t11:
M840itfnTa$0n+|tu,lagsc+l M8süü I M8s0F lMts0G DTg3CIF+I M1000
S0m tlO,5Yo +3 t{0.1%+
2V *(0.8% +2) (0.2%+2)
28V
200v
1 000v r{ 0% +3 *(0,20Á +5
lnptf impedanffi: 1üM$ on allrang*
Frequency rangs: 40 * 400H2
*(2'B%+
fr¡leasuring vcttage drap: ?0ümV
Measuring voltage drop: Zü$mV Frqquency range: 40 * 400H2

li¡lNüf: ;\{lCl;lii\tiY
M840Dt M89üG I M890C+ IMSSODl M890FtDT890B+tDT930F+t M1000
?a *{1 .o% +
Kf¿
{1 .0% +5}
200K a
2M0
zOM ft
200M É2 {5.0% (i* H{ -10)+20:# i
6)
7) & M8g0G only)
Sensitivity: 100mV nns
4. rnr*
1) Be sure that battery is mnedly placed in the battery case and
conneded to the battery snap,
Dant exred Ste input limit shou¿r below:
Functi*n Range lnput terminals Maximum input
DCV 2OOmV
V/SHM COM
250VnC
A*V 20ümV 25OVAC
DCV 2*1000V 1 000vDt
ACV 2-750V 750VAC
OHM V/OHM COM 2S0V DCrAC
Frec. VIOHM/Hz COM
Diode VfOHM COM
DCA 200m4 A COM 200m4 DCfAC
ACA 2ü0mA
DCA 2A 2A DC/AC
ATA 2A
DCA 2OA 204 coM 20A DCIAC
3) lnspec't tlrc test leads for darnaged lnsulation or expo$ed rnetal.
Chmktest lead mntinuity. Damaged leads should be replaced"
4, $elect the proper func'tion and range for your meásurement.
5) Chepk tfre input tenninal position far red tmt bad trpends on
measufement ranges.
40$c * 100st'
Wih ffiype thermmuple wire
8} FREEUHNCYMEA$UREMENT

6)
7)
8)
Ei$er one of tfre test leads should h taken offfrom he circuit under
test w,len changing he test ranges.
lb avoi'c eledrical shock or damage tb üle meter; Do not apply msre
then 500v between any terminal and eartrr gn:und. - r t-.1
To avoid elecfrical shock, use caution wñen rarcrking above 60wc
or 25VAC rms, such voltage po$e a shock hazard.
9) when finished the measurernent, switch off the pou€r. Be sure to
rcmüve the battery when it is not used for a long time to avoid leakage
problem.
10) Do not tamperwih flre ciranitry to avoid damage.
11) Do not use or store the'instrunrent in a plae of direct sunlight, hlgh
ternperature and high humidrty
5. -MEIHOD OF TFTEASURTN¡CrIT
5.1 DCV & ACV MEASUREMENT
1) set the Function range swttch at the required position.
2) CCInnect black tmt bad to 'CCIM" terminal and red te$t lead to tre
'VIOHM" input tenninal.
3) Conned test leads to measuring point and read the display value üre
polarfu of üre red lead mnnedion will be indicated at the sarne t¡me ii
the vofhge.
Noüe:a)
b)
c) Never try to measure the voltage above 1000v1 Alfrough he
indication is pssible t'0 show, there is a danger of darnaging
the internalcircuitry.
5;2 DGA & ACA MEASUREMENT
1) Connmt the black test lead to the "COM" terminal and fre rcd test
' lead to "A' terminal for a rnaximum of 0.5A (mqdel Mg40D **¡*u*
2A)
2\ set fre function range switdr at tlre requird position.
3i Conned test leads to measuring poinh and read fre display value.
The polanly at the red test lead mnnedion will be indicated ait tne sarne
time as the cunent.
l! the volbge to be tested is unknown beforehand, set the
-fqnction{anüe switch to fre highest range and r¡¡crk dovur.
]n{.en only the figure "1" ir displayed-over rangq is being
indicated and the func{ion range switc*l should ne set to á
higher range.

Note: lf fre cunent range is unknawn hforehand, set'the furxfion
range switch to the highest range and urork down.
Wnén only the figuré "1" is displayed, over range is being
indicated and fre fundion ilange suntch should be set to a
higher range.
f;xcessive current will belaw the fuse frat must be replamd
when the input is fom "A' termlnal. Fuse tlpe is 0.5A (fflodel
M840D use 2A).
A fuse dres not proted he 20A range; rnaximum 10A
mntinuous or ma<imum ?04 rneasuring üme rnust be less
han 15 seconds.
5.3 RESISTAT{TH MFASUREMHNT
1) Conned black test lead to 'COM" teffninal and red te$t lead t'r the
'V/OHM" input terminal.
2t $et fle func{icn range switch to $le OHM range.
3) Connect the test leads acro$$ fie resishnm under rneasurement
and read the display value.
Note: The plarity of üre red test lead i$ "+".
When fre input is not mnnected, i.e. at CIpen circuit, the figure
'*1" \¡uill be displayed for the over range condition.
lf tt're resistane value being measurcd exmds the rnaximum
value of the range selected, an over range indicaüon "1" will be
displayed and function range swthlr should h set to a higher
range.
?00Mfi range has a 10 db¡ts (1Mn) mnstant, fte figure will
appear in short ciru.¡it sbtus, it should be subfacted fom
rneasurernent result, for instance: when rneasuring 100MCI
resistor, figure 101.ü will be shown in display and the last 10
drgit$ shauld,h subtracted
5.4 CAPACITANCE MEA$UREMfr NT
1) Set the fundion range switch at ttre "Ct'' psition. Before mnneding
the capacitor, üre display muld h zeroed automatically slows.
2) Connec{ the test capacitcr to the "Ct'' input socket (not test leads
and read the display value.
Note; The tested" capacitor should be dischargCId befare tfre tmting
a)
b)
c)
d)
a)
b)
c)
d)

i prmure. Never appty voltage to the "Cf input socket, " or
i Carnage may result.
i 5.5 FREQUENCY MMSURETT{ENT
. I 1) $et the function range swttcfr at he required 't{2" position. i
: 2) Conned test leads tr¡ measuring pinb and ead üe display value. :
i Note: Do not apply more than ?50V rms trr fre input. lndicaüon is i
i possible a voltage nigf'er than 100V mts, but read¡f€ maybe out of i
I ;fmP**tuRE MEA''REMENT i
i f I $*t the function range switcfr atthe -THMP' position. I
i Zj Be sure the polartty of the frermamuple, p$ re coH sd (ftee end) i
i af the tlnrmocou$e sensor into the temperature testing holes. i
I gl Tl're wurking end {testing end} on sr inslde the o$ed beirg te$ed I
i 4) The value of fre temperature is shown on fre display in degrees i
i ' mnügrade ("C), ¡
:
The testins temp€rah.¡re ls displayed automatically urten th* i
thennqmuple is put intrr the testing holes.
The sunounding temperature is shown when he cirsilt of the i
sensor is tx"¡t off. :
The limit temperature measured by the thermomupb given !
together wtth the instrurnent is 250"C; 300'C is amptable i
within sho$ p*riod.
i s.I DIODE & CONIINUITY TEST
I tl $etthe fundion range swftch atthe "{F-!" position.
i Zl Conned fre black test lead to "COM" terminal yd fed te$..lead to ¡
i 'V/OHM" inputtenninal; {Note: fre polartfy of the red test lead is'+"). :
¡ 3) This range wfth 'AUDIBLE CONTINUIry TE$T' tundion. Built'in i
i 'buzzer sounds if the resistance betwmn two probm is less tlran i
: L,,Ll¿'j.E¡ {
i as!10fi.
. ar\JL l v¡¿.
I ¿l Connect frá test leads acrCI$$ fre diode and read the display value. ia
a
i *o**tr) Vrthen the input is not connected, i.e. at opn circuit, Ure ngure i
b)
c)
"1"will h displayed.
b) Test condition: Foruard
SC voltage áFprox. 2.8V.
:
DC cunent approx.lrrA. Reversed ¡
'i
c) The meter displays the fon¡rurd voltage drop and displays i
a*

figure "1" for ovedmd wlren the diode is reversed.
5.8 TRANSISTOR hFE TEST
1) $et the function range switcfr to Sre "hFEu position.
2) Make $ure the transistor i$ "NPN" or "PNP" type.
3) Transistor c*necily insert in E.B.S @nnector.
4) Display reading is approx. fansistor hFH value.
Note;
Test mndition: B-ase cunent approx, 10uA, Vss approx.z.8v
II
a/
a
I
.t
6.F
1) Battery and fuse replaoernent sfrould only h done after the test i
leads have been disconnecffi and power is off. j i
2l Loosen $crfi^É with suihble scre\ildriverand remove case büom. I
3) The r¡eter is power by a single 9v batt*ry {lEC 6F?J, NEDA 1604, i
Jl$ 0ü6F), $nap the battery mnnecürr leads to fre terminals of a new i
battery and reinsert the battery into the case top. Dress fie battery !
leads so that fiey will not be pinched betr¡rreen ffre case hottorn and i
case top.
4) The meter is protected fast tuse 0.5Atr50V (mdel M840D
proteded fuse 2A#5$V onlyi, dirnensions is 05?0mm.
5) Replace the mse bottom and reinshll üre three $crevte.
operate fie rneter unless the case bottom is fully ds$ed.
AWARRAI{TYA
Warrants this instrument'to be free frorn defects in
rnaterial and workmanship for a period of one year.
Any instrument found defective within one year from
the delivery date- and returned to the factory with
transportation charges prepaid. W¡ll be repaired,
adjusted, or replaced at no charge to the original
purchaser. This warranty does not cover expendable
items such as batteries or fuses, lf tl're defect has
been caused by a rnisuse ar abnormal operation
conditions, the repair will be billed at a nominal cost.