Heathkit HD 1982 Schematic

Page 1

WAVEFORMS

: KEYBOARD I : CIRCUIT BOARD TIT :
I H ! A one +
: - __ a <59 ' T ' l 9 ° I
l T. I c209 l
I ' g .047 :
l I
: : 33.3. .... . : 9123 _
' :::.:: ..: (705 I 22 '-
I : 047 I
' L I """ v VISUAL l
: : FEEDBACK :
. O I I I E SWITCH I
: T : 437'02101 " f3 :
I II .3 °I . a A»? .2 I ---
T I l I :1: 3g; OggLEE-Ega EDD-43' m, : MICROPHONE
- [ ' {I _ O . .4"; m "-55:
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E ' 5 . 6'1 g I V w AMPLIFIER :
'I 4'2'
I F' l RNG + I
5 L7- F3- 9 5 ' ©. W ' ° ,, (~- 5 $5552: __ comm
"-CI .
I 91:] E |# GI---. g 22 gm '22 I ---------- CTRCUIT
I I ' .9175 R122 ©RED AU D IO
I l VW 35 10K H, h .
I 3 fig? 330K . c114 I 1/ 7K . ---------- .
I | ' .047 1 , SHIELD
l cl §CIo4- c105 ' . _ GROUND
I I .. 18 .047 C1011: ' BLK
T I 30"; V 32' $7.5 .. Q3) 0
I I
I 3| I
e \7
E i V E
l .
: A: ...... HIGH TONE : NOTES'
. I a +002 OSCILLATOR I
I : $033 I 1. REFER TO THE CIRCUIT BOARD X-RAY VIEWS FOR THE
T I M : PHYSICAL LOCATION OF PARTS.
I I MK ' I
: I V °°' : 2. PRECISION RESISTORS ARE 1/8 WATT, 1% TOLERANCE.
: : l REMAINING RESISTORS ARE 1/4 WATT, 10% TOLERANCE.
I I : RESISTOR VALUES ARE IN OHMS (K=1000, M=1000,000).
I I I
T : T 3. CAPACITOR VALUES ARE IN- OF.
L------------ ----- --J h-------------- ----------------------------- fl------------------H--------J I
A B C D E FG H 4. DC VOLTAGE MEASUREMENTS WERE TAKEN WITH A HIGH
I. . . INPUT IMPEDANCE VOLTMETER FROM THE POINT INDICATED
2 . . . SCHEMATIC OF THE T0 CIRCUIT BOARD GROUND. VOLTAGES MAY VARY 110%. .
3 O. O . A .
4 o 10 o tymv HEATHKIT® _ s. O THIS'SYMBOL INDICATES A DC VOLTAGE WITH NO
5 O O O TONE BEING PRODUCED,BUT PTT SWITCH SWlOI DEPRESSED.
e e e ' e - MICODER' '
7 ° ° o ..,. .- e 6 THIS SYMBOL INDICATES A DC VOLTAGE WITH KEY
E__JJ._.._...° . - .
3 .. : : FC J] :1: u .H WWW... MODEL 0 1982 "1" PUSHED ANO PTT SWITCH sw101 DEPRESSED.
* . .. e :3 I336 147;
0 0 .0 . COpyrlght©I976 T. v THIS SYMBOL INDICATES CIRCUTT BOARD GROUND.
4 O 0 Heath Company
.TNDTCAYES TERMINAL suomo Q======JJ Allnghts Reserved 8. 0 THIS SYMBOL INDICATES A CONNECTION TO THE CIRCUIT
3,5213 EY 5 IDENTIFICATION BOARD.
VERMINAL H Is COMMON OF KEYBOARD PINS TWO-TONE OUTPUT FREQUENCIES FROM THE MICOOERTM .
9. THE WAVEFORMS SHOWN WERE OBTAINED BY PUSHING

KEY "1 WITH PTT SWITCH SWIDI DEPRESSED.