Sencore FE16, FE14 Service manual

INSTR UC TI ON MANUAL F OR TH E S E N CORE FE1 4 & F E16

Th e S e n c o re FE14 and F E 16 F ie l d E f fe ct M et e r s are a rev o lution a r y new co n ce pt
in te s t m e t ers. The y take all the a dv an tag es of a V TV M and c o m b i n e them with

the ad va nt ag es of a VOM to m ak e an e xtre mely versatile me t er. High input i m
ped an c e on all AC & DC v olt ag e r a n g e s , pe ak to pe a k AC me asurem e nts, & DC
zero center sc ale s com bi ne d with z e r o wa rm up ti m e , DC c u rrent r a n g e s , and
VOM p o rt a b i li ty m a k e s the Fi e l d E f f e c t Mete r a tru l y great inst r u ment . Anyone
in the el ect r i cal o r el ectr onic field s - s erv i c e t e c h nicia n s , engin e ers, fiel d eng 
in eers , ha m s , e x peri men t e r s e t c . - wi ll find that the Fi e l d Effec t M et e r is the
co m p l e te an s w e r to h is measu r i n g needs.

No othe r mete r in the F E14 o r FE1 6 cl ass has a l l of the s e fe atur e s in one ins tr u ment:

* High input imped an ce on both AC and DC v o lta g e ra nges (1 0 m e g oh m s ,

and 15 megohm)

* T r ue p e ak to pe a k AC ran g e s .

* Z ero ce nter r a nges fo r s olid s ta te s e r v i c ing.

* DC cu r r ent ran ges fo r genera l test in g.

* M i r r ored scal e mete r fo r great e r a c c ura c y in readings .

* Mete r pro te c t e d fro m o v e r lo a d s .

* C i r c uit p r o te c te d fr o m ac c id e n t a l app li ca ti on of w ron g vo l ta g e s.

* All s t e e l con s t r u c ti o n for g r eate r du ra bi lit y .

FI ELD E FFE CT METE RS

* B at te r y op er at ed fo r complet e por ta b ili ty .

FE14 S PE CI FI CA T IO N S

DC VOL T S
Ra nges : 0 to 1, 3, 10, 30, 10 0, 300 and 1000 FULL SC A L E

Input Res i s t a nce : 1 5 meg o hm s shunted by 14 PF .
A c c u r a c y : + 2 1/2% »
AC R eject i o n: 3 0 to 300 times (3 0 to 50db).

AC VO L T S
Ra nges : ( R m s )

Ra nges : ( P eak to Peak)

Input Resi s t anc e : 10 me g oh m s shunted by 29 PF .
Fr e quen c y Re s p o n s e : Flat : 25HZ to 1MHZ

A cc urac y : + 4 1/2%

- .5 to .5 , - 1.5 to 1 . 5, -5 to 5, -1 5 to 15 , -50 to 50, -150 to 15 0
and -500 to 5 0 0 ZE R O C E NTER S CAL E RAN G ES

0 to 1, 3, 10 , 30, 10 0, 3 00 and 1 0 00 FULL SC A L E
0 -2 . 8, 8.4, 28, 84 , 2 80, 840 and 28 0 0 F ull Sc a l e , fr e q ue n cy

com p e n sa te d

3db po i nt s : 10Hz to 10MHz

OHMM E T E R
Rang e s : 0 to 1000 o h m s , 10K , LOOK, 10 me g o h m s and 1000 mego h m s
A c c u r acy: + 2 de g rees AR C

DC CU RRE NT MEAS U REME NTS
Ra nges: 0 - 10 0 m icroa mps , I ma, lOma, lOOma and 1 A m p e re
A c c u r a c y: + 3%
In te r n a l Vo l ta g e D rop : 200 MV

F E16 SPE C IF IC A T IO N S

DC V O L T S
Ra nge s : 0 to 1, 3, 10 , 30, 10 0, 300 and 1000 FULL S C ALE

Input Res i sta nce : 15 meg o h m s shunted by 14 PF a t jack or 37 PF th ru cable
A c c u r a c y: + 1.5 %
AC Rejec t i on: 30 to 300 t i mes (3 0 to 50db),

AC VO L TS

R a n ges: (Rms )

R a n ges: (P ea k to Peak )

Input Resistance : 10 meg o hm s shunted by 29 P F at ja ck or 118 P F thru ca ble
Fr e quency R e s p onse : F l at: 25H Z to 1MHZ

A c c u r a c y: + 3%

OH MME T E R
Ra nges : 0 to 10 00 oh m s , 10K, 10 0K , 10 me g oh m s and 1000 mego hm s
A c c urac y : + 2 d egre e s ARC

5 to . 5, -1. 5 to 1. 5, - 5 to 5, - 15 to 15, - 50 to 50, -150 to 150

and -500 to 500 ZE RO CE NTER SC A L E R A NG E S

0 to 1, 3, 10, 3 0 , 1 00 , 3 0 0 and 1000 FU LL SC ALE

0-2 .8 , 8 .4, 28, 84, 2 80 , 84 0 and 2800 F ull s cale, fre q u e n cy
compen s at e d

3db p o in t s : 10H z to 10MHz

DC CU RRE NT MEAS U REME NTS
Ra n g e s : 0 - 10 0 micr o amp s , I m a, lOma , lOOma and 1 A m p er e
A c c u r a c y: + 3% fu ll s c ale
Int e r n al V o lt ag e D ro p : 2 00 M V

G E NERAL SP E C IF I C A T IO NS ON FE14 AND FE 1 6
Meter: 4 - 1/2 ", 10 0 micr o a m p + 2%, diode p r otec te d and is o l a te d fr o m input
M u l t iplier Resis tors: 1% prec i sion type on F E14; 1/2% on FE16
Oh m s B a t tery: 1. 5V "C" c e l l , Evere a dy Type # 10 35 o r e qu i v al en t
Powe r supply ba t t e r y : 9 volt, E v e r e ady Type #222 or eq u i va le n t
Weight ( l ess Batt eries): 3- 1 / 4 lb s .
Di mens i o ns: 5 " w x 7-3/16 ”h 3 - l/l 6d

Acces sorie s: High Vo l ta g e pro b e (3 9 A19 ) ext en d s ra nge to 30K V.

CO N T R OLS ON THE F E14 & FE16

The Fi e l d Eff ect M e t er is a s s i m p l e to ope r a te a s a s t an d a r d VOM. P an el c o ntro ls
inc lud e the RAN GE swit c h, FU NC TI ON sw itch , met er ZERO ADJ, OHMS AD], and
the of f - o n switch. T h e follow in g is a b r i e f d e s c r iption o f ea c h c o n t r o l and how it
is used.

O FF-ON sw itc h : T h e OFF -ON switch co n t r ols the pow er to the circu i t in the Fi e l d
E f f e ct Me t e r . In the OFF posit io n, the ba t t e ry i s di sc o n n e c te d fro m the ci r cuit
and the me t er is off. In the ON position , the ba t t e r y v olt ag e is applied to the cir cuit
and the m e t e r i s re a dy to g o. A r ed fla g ap p e a r s in the swi tc h openi ng to indi ca te
when the Fie ld Effect Mete r i s on. When m easu r i n g cu r r e nt, the OFF-ON s wit ch
ma y be left in the O FF pos it io n as no b a t te r y powe r i s need ed.

ZERO ADJ: T he ZE RO ADJ i s used to p o si ti o n the po in t e r of the met e r o v e r the
zero on the ex t r e me l ef t of the meter s cale o r to p o si ti on the po i nt e r on the cen te r
zero when us ing the ze r o ce nter ran ges of the Field E f f e c t Meter.

OHMS ADJ: Th e OHMS ADJ i s the sam e a s that found on mo s t m ete r s . P r ior to

m e a s u r i n g r e sist a nce , the tes t le a ds a r e sh o rt e d tog et h er and the OHMS ADJ is
ro ta t e d f o r a full s c ale defl ec ti o n (z e ro o h ms) as rea d on the ohms s cale o f the
m e t er.

FUNC TIO N SWIT CH: Th e FUN CTION sw itc h se lec t s the type of meas u r e ment to be
pr e f o r med. Min us o r Plus DC Volts or MA, AC vo lts o r OHMS and the BAT T . CHK.

RANGE S WITC H: The RANGE switc h select s the d e s i r e d ran g e of cu r r e nt, voltag e,
or r esistance to be me as u r ed .

SH I E L D E D LE A D ON T H E FE1 4 & FE16

Th e Sen c o r e Fi e ld Effe ct Meters ar e equipped with a shiel d ed lea d cm .the po s it iv e
input lead so that a c cura t e AC me asur e men ts ca n be made in the presen c e of
str o ng elec t rost atic and m a gn e ti c fiel d s . T h e s hi el d, which i s a l s o ef fectiv e on

high ohms ranges , is only con ne ct ed when u s in g the AC Volts / O hms fu n ct io n s and

is d is c on n ec t ed when mak ing DC meas uremen ts to p re v e nt capac i t ive loading of
the circu i t being mea s u r e d .

T est l ea d co n ne c ti o ns to the F E14 or F E16 a r e made through the re d and b la c k
bana na jacks . T h e shi el d c o n n ec t s through a s mall pin j ack ( p la in ly ma rk e d) so
that it cannot be m i s t a k e n l y used a s one of the te s t lead co n n e c ti o n s .

OPE RA T IN G THE FE14 and F E 1 6

The Senc o r e Fi e ld Effe c t M e t e r s a r e s i m p l e and ea s y to o perat e . Set the Fu nc t io n
swi tch to the d e s i re d t e st to be pref o rmed, the RA NG E switc h to the de s i r e d rang e ,
co n n e ct the lead s and r e a d the re s ults on the me t er. H er e is a b r i e f de s c r i p t ion of
how eac h te s t is pe r fo r med.

READ IN G DC VOL T S : To rea d DC v olt s, th e F u nc t io n sw i tch is se t to eith e r plus
or m inu s DCV/MA. T he Ra ng e sw itch is set to the des i re d r a n g e of volt ag e f r o m
one volt' to 1000 volt s full scal e . If the volta g e to be me a s u r e d i s unknown, st art
with the hi gh e st ran ge and w ork down until t he vol ta ge can be m e a s u r e d. Co nn ect
the le ad s to the c ircu i t and rea d the re s ults on the m e t er. When measur i n g voltag e
in R F-IF ci r c uits , a 10 0 K iso l a ti on r esi sto r at the end of the re d te s t le a d will
re d uce cap a c it i ve e f f e c t s without e ff e ct i n g a c cur a cy of r e a d i n g s .

The DC vo ltage i s re a d on the two blac k s cales ju st above the mir ror on the me t e r .
Th e top DC sca l e i s fro m zero to 1 . 0 volts and e a ch mark is e qu a l to .02 vo lt s.
Th e b o t to m sc a l e is zero to 3. 0 volts and eac h marki s e qu al to . 1 v o lt s. Th e z e ro
to 1 . 0 sc ale is us e dfor the 1, 10, 10 0, and 10 0 0 volt r a n g e s and the ze r o to 3 . 0

sc ale i s used for the 3, 30, and 3 00 volt r ang e s . In use the m e t e r in di ca ti o n is
mu lti pl ie d by 10, 100, o r 100 0 depending upon the ra n g e . For exa m p l e , i f the

ra nge sw i tc h is on the 10 volt ran g e and the meter reads . 42 vo lts , the actu a l v o l 
tag e i s . 4 2 t i mes 10 or 4. 2 volts DC.

RE A D IN G AC VO L T S : To read AC vol ts , the Fu n c t io n s w it c h i s s e t to the ACV/OHMS

po si ti o n and the Rang e sw it ch to the desi r e d r a n ge. For RM S volt ag e s the two

bl a c k s cal es mar k e d AC (RMS) a r e used. For pea k to peak vo lta g es , the two red
s c ale s dire c t l y be low the AC (RMS ) scale s are u se d. The rea d i n g s a r e multip li ed
in the same way a s with the DC s cal es, to obtai n the ac t u a l voltage pres e nt. On
the z e r o to 1 .0 AC (RMS ) scal e, each mark is . 02 vo l ts and on the zer o to 3. 0 vo lts
scale, ea ch mar k is . 1 vo l ts . On the ze r o to 2. 8 vo lt s AC (P-P) s c a l e , ea c h mark

is . 1 v olt s and on the zero to 8. 4 vol ts sc a l e, each mar k i s . 2 vo lts .

REA D IN G DC VO L T S ZERO CE NTE R SC ALE: T h e z e r o ce nter s cales a r e used to

re ad plu s or min us vol ta g es without the necessit y of c ha ng in g pola r i ty with the

le a d s or Fun c tio n s w itc h. To us e the ze r o c e n t er s cal es, set the Func tio n switc h
to plus DCV/M A p o s it io n and adj u s t the ZER O ADJ until the meter r e a ds at the

z e ro m a r k in the cent e r of the s c ale . This gi v es r a n ges o f plus or min us . 5 volt s

(top sca l e) or pl us or minu s 1. 5 vo l ts (botto m sc a l e) ti mes 10, 10 0, o r 100 0 de
pending upon the se tt in g of the r a n ge swi tc h . If the ran g e swit ch is in the 300 volt
po si ti o n , the zero to 1. 5 vol ts sc ale i s us ed and bec ome s zer o to 150 volt s pl us or
mi n u s. If the meter swin g s up sc ale or to the righ t , it is a po si ti ve volta ge . If
the mete r swings down scal e or to the le f t , i t is a n eg e ti v e vol ta ge . Th i s unique
fe a t u r e a ll o w s you to det e r mine th e po l a r i t y as w el l a s the am p litu de of a DC vol
tag e and i s ve r y handy in so li d st a t e serv i c i n g .

REA D IN G OHMS: To re a d resi s t ance, se t the Fun c ti o n sw it c h to ACV/OHMS and
the Ran g e swit ch to the des i r e d ra n g e of resi s t ance to be read. Aft er c h e c k in g to
see that the meter i s "zeroed " at the le f t edge of the s c ale, short the lea ds to g e th e r
and ad j us t the OHMS ADJ con t r o l for fu ll s c ale de fl e c t ion o f the m e t e r . U ns h or t
the le a d s and be sur e tha t the m eter r etur ns to the ex t r e m e l e ft of the scale. Plac e
the unknown r esistance b et we en the two lead s and r e a d the resist anc e on the Gil VIS
scale (top re d s cale on m e t er). Mu lt ip ly the rea d i n g on the meter by the ran ge
use d. For ex a mple, if the m eter r e a d 15 and the ran g e switc h was s et on RX1 0 0 ,

the ac tu a l resista nce would be 15 times 1 00 or 1 5 0 0 oh ms. CAUTION : When mak
ing o h m s m easu r eme n t s , be su r e t ha t the p o we r to the c i rcuit is tur ned off . The
ap p li ca t io n of e xce s siv e vol t ages to the RX 1 , R X10, and RX100 ohm s r a nges ca n
da m a ge the i n t e r n a l s tan d ar d r esist or of the Fi e l d E f fect Mete r .

MEA SU R IN G DC CURR E N T: To mea sure DC cu r r ent, the Fu nc tio n s wit ch is s e t
to eit h er the plus or minu s DCV/MA pos it io n and the Ra n g e switch to the d e s i r e d

ra nge of c urre nt. Th e powe r to the F ield E f fect M e t e r d o e s not have to be turned
on and may be l e ft off to co n s erve on ba t te r y li f e if you s o desi r e. C o nn e ct the

le a d s in serie s and re ad the r e s ulta n t c urre nt on the met e r . The 0 to 1.0 DC
VOLT S (MA) scale is u se d o n all curr e nt me a surements . If the met e r r e ads b a ck

wa r d s , in d ica t in g that the lea d s are r eve r s ed, simply chan g e the p olari ty with the

Fu n c t io n sw itc h to the op p os it e polari t y and the m eter will read up sc ale.

MEA S UR IN G HIGH V O L TA G E WITH THE F E14 AND FE 16

CAU TI ON : High voltag e i s dan g er o u s and c a ut i on should be ob se r v e d when m e a-
su r i n g high volt ages. Be su r e tha t the ground lead fr o m the Fi e l d E f f ect Me t ei is
co n n e ct e d to the ground on the unit. If the ground lea d is not co n n ec te d , you θ ί β
mer ely exten di ng the high v o lta ge c l oser to you. Stand away fro m the unit you a r e
m e a s urin g and keep o ne hand in your po ck e t a s a sa f e t y measur e . High volta g e (Π
color TV is e s peci a l l y da ng e ro u s be c a use it can go a s high as 30, 00 0 vo l ts and

re g u l a t e d . If you should co m e acr oss it, it will not load down.

IS