Heathkit HD 1986 Schematic

Page 1

SCHEMATIC OF THE
HEATHKIT®
MODEL HD-1 986
MICROLIZER

NOTES:

1. ALL RESISTORS ARE 1/4-WATT, 5% UNLESS MARKED OTHERWISE.
RESISTORS VALUES ARE IN OHMS (K=1.000.M=1.000,000).

2. ALL CAPACITOR VALUES ARE IN uF (MICROFARADS) UNLESS MARKED
IN pF (PICOFARADS).

3. O INDICATES A WIRE CONNECTION ON THE CIRCUIT BOARD.
4. "é" INDICATES A CHASSIS GROUND.

5. v INDICATES A CIRCUIT BOARD GROUND.

e. O INDICATES A Dc VOLTAGE (120%) MEASURED WITH A HIGH
IMPEDANCE VOLTMETER FROM THE POINT INDICATED TO
CHASSIS GROUND. ALL MEASUREMENTS WERE TAKEN WHILE
THE FILTER WAS BEING POWERED BY A 9-VOLT BATTERY.

r---------------------------------------------------- ----- .---------------------------------------------------------

MIC GAIN

9 'VOLT -

BATTERY _ m

R11
IOK

AUDIO/OUT

GND

9 -..-------..---....--------..-........---..---..-----..---..---..

GND

-.....--....--- Q -....

J 2
MICROPHONE /0UT