Heathkit IM 2420 Schematic

Page 1

-.:--_DTSI-L-AF;]
cmcuu
5" BOARD :

I New :IECDJER
DRIVE PS

mm m. Wm) SCHEMATIC OF THE
; HEATHKIT®
o A I A , ;
MAI FREQUENCY COUNTER
0 flux: MODEL IM-2420
' : > 1* WV NOIES:
o Um (, I. ALL RESISYOR VALUES ARE IN OHMS: K'l.000: M-I,000.000.

Z. All RESISIORS ARE II WATT Si. UNLESS MARKED OTHERWISE.

"noon

DECADE
k _________________________________________________________ 023 .025. W
5 z I

LEVEL

nu sum-n 0 y
mnazn ., mg

T MDEBAND m AMPLIIIiR mpux SELECTOR PULSE 5MP cow, mm" sgucmp

I n. . m. o
1 A nu fin

wpw A Humfl

INPUYA i
In: a! o ' a. «muss mam: omnmsz, CAPACIIOR VALUES GREATER THAN
; ; 9 1.0 ARE IN PIcorAnAos. AND VALuEs LEss mAn Lo APE m
_ "y ¥ " mcnorAnAns.
lb a» £3 I A. '4' nus svmnot INDICATES CHASSIS okouun.
Efigfiéw a k : 5. ¢ nus SVMIOl INDICAIES clncun IDARD cnouuo.
, f 5 o. nus svmm snows ruAr mt INDICATED COMPONENI IS
"V D.J.32a°ci?5~ we use was TIE-°--,-a'-g-;i*§j- u 02 F 7 w 7 7.4 MOUNTED on IE CHASSIS.
Y "Rum .. 1' o : 77-; 1. 0 ms SYMBOL INDICATES WHICH or IHE WAVEFORMS snovm
: sf WILL I! rouun AT IHE INDICAIED Pom. WAVEFORMS An:
I; 9 g g r 1 ; . IAKEN WHILE AcmAuv MEASURING AN INPUT (ANY
, 'nxm . ACCEPIAILE mouEucw.
, I J
P Y B DIVIDF BY TEII '
amn'c'? Emma wchAND a, .,v mu _ > :1! I E x. 0 ms SYMBOL mnvans A we VOUAcE IAKEN mm A HIGH
mu-m V COM/WW mm . .. ____________ .4 INPUT mPEoAncE vourmzn mum m: POINI mochIEn
7 1 , AND anouun wnn no INPUI SIGNAL. voLrAcEs MAY
5,, , ' I VARY not
. r: I
__4 ; 7 . 9, ms SYMBOL Is usn IO INnICAIE wmcn Ic's ARE PowEnEn
.5, 55% I . 0 av oil.
3 1 . I swz _
. E ............... . RANGE OWL Pom, was , II). 0va HEATER cournm vomcEs ARE MEASUIIHI mm m:
M $- . o , a" . STYROFOAM coVEP IN PLACE.
Q , . i
i u I V
3 : u. vomoEs MEASURED on m: INPUI A AND INPUI a couvmmzs MAY
IE I . 1 BE mum or m: "40 vqus suown. INESE An ESSENTIALLV
hm : an: m - , I Win-POSITION oEVIcEs. AND MAY CHANG! srAvE wusu ms

o L "7.. _ voUMEtEa PROBLIS mmooucso.

- IZ. VRIGGER CONTROL RO-SWI l5 SHOWN IN MID POSITION
lNDT PRESHI.

THERMISTOR RESIS'ANCE: AIOUY ZDKO IV 29": AND 13000

"nun-43:!"

wxzvvv AWN' (mum a) I).

A.____.4.l.__...___

. I
............................... -----~-1 i 55-42% AI ISC.
OSCILLATOR . I u I I u PARIS m SHADEII AREA ARE cnmcu FOR co
IR UIT some n. - NTINUtD SAFE".
c c 3m : : o E 0 f ' REPLACE mEM ouLv mm PARIS or 1H: SAME nArmc on wnn
_ W, , , , 1H! PROPER NEAIH PAns.
* E?" {75.92: M: w ..

mm. OSCILLAmR ouwuv

1..
PE : , ' - ir-J's. L? i
U """" 1 an m» ' .UM '
72:33:23 . . w Pow s u o v g WAVEronM nous
J : V mama ,4 ' ;
. n-m-I- r, <§ é I .
g m '- use I J
9.. .4 I. wAVEroIms ARE IAKEN mm m: RANGE swncn m m rum
ccw POSIIION. runumc INE swncn m IHE cw nmcnou
65: (2': J": mu. AuER THESE "MES 10;
L; "" loomSEc. I SEC, AND In no
_ w) a 2. wAVEronMs ARE mm mm A man QUALIIV. mcn
r- u w .m IMPEDANCE oscmoscoPE. WAVEFORM D MAY may aE SEEN
I "ng , " ' mm AN oscluoscoPE IN IS cAPAaLE or 30mm on MORE
: _ . _ W, RISPONSE.
.
I, ~ 3 'm m, 3. WAVEFORMS A ANII a APE 'IAKEN mm A 'IVPICAL lmuz. zoo-av
in: w w v L . b P-P) INPUI APPLIED to In?!" A.
I I'- I T I I I. wAVErom 1 IS 'IAKEN mm A TYPICAL uomuz, zoumv P-P)
m a ., . . .. .. . n - - 920 :m IuPu1 APPllED m INPUT 3.
. m m.
: U. J u. 2345' u: us U7 ma un UZI -"' s. WAVEFORM El IS TAKEN mm IHE lANGi swncn m m: wuv
I , 'num '«nc r ham- um- hws huw Im- a T 1' , ccw Posmou. WAVEFORM Ez snows uow ms WAVEFORM
L "" - 0 egg WILL cuAucE mu mE RANGE swncn Is warm; on:
fi-«Tm\_ I . . E _ r P P T 1' 1' 1 <7 POSITION IN IN! cw nmcnou.
"no §
Capynw©mo
mum Company

All Rights Rama
Pun of 595-23M~05 mu m n. W sun. at Arme-