Heathkit ID 1990 Schematic

Page 1

SCHEMATIC OF THE
HEATHKIT®
DIGITAL BAROMETER

MODEL lD-1990

NOTES:

1.

10.

Part of 595-2425-O1

COMPONENTS ON THE CIRCUIT BOARDS AND REAR PANEL
ARE IN THE FOLLOWING GROUPS:
1» 99 PARTS ON THE REAR PANEL.
101-199 PARTS ON THE DISPLAY CIRCUIT BOARD
201-299 PARTS IN THE OVEN ASSEMBLY.
301~399 PARTS ON THE ANALOG CIRCUIT BOARD.
401-450 PARTS ON THE SWITCH CIRCUIT BOARD.

RESISTORS ARE TIA-WATT, 5%, UNLESS MARKED OTHERWISE,
VALUES ARE IN OHMS Ik-IOOOI.

CAPACITOR VALUES LESS THAN 1 ARE IN LIF. CAPACITOR

VALUES MORE THAN 1 ARE IN DF UNLESS MARKED OTHERWISE.

0 THIS SYMBOL INDICATES A DC VOLTAGE MEASURED
FROM THE POINT INDICATED T0 GROUND.
MEASUREMENTS WERE MADE WITH A HIGH INPUT
IMPEDANCE VOLTMETER.

\.,,:e

VOLTAGES SUBJECT TO CHANGE WITH PRESSURE
TRANSDUCER VARIATIONS.

m.

R7 THIS SYMBOL INDICATES A CIRCUIT BOARD GROUND.
THIS SYMBOL INDICATES A REAR PANEL GROUND.

".9>- THIS SYMBOL INDICATES A PLUG-TO-SOCKET
CONNECTION. THE NUMBER FOLLOWING THE PLUG
NUMBER INDICATES THE PARTICULAR PIN NUMBER.
FOR EXAMPLE: P101-1 MEANS PLUG P101 PIN 1.

O THIS SYMBOL INDICATES A WAVEFORM DISPLAY AT
THAT POINT, THE WAVEFORM FREQUENCY AND
AMPLITUDE ARE SHOWN ON EACH DISPLAY.

PARTS IN THE SHADED AREA ARE CRITICAL TO CONTINUED
SAFETY. REPLACE ONLY WITH THE SAME RATED PART, OR
WITH THE HEATH COMPANY PART NUMBER, IF SHOWN.

Copyrlght © 1980
Heath Company

All Rights Reserved
Primed In The Unlted Slates of America

I
I
I
|
|
In
I5

L-

G 1V/DIVISION

________ -j

[SWITCH CIRCUIT BOARD

swaoz sw403 swam

m m [ME

WAVEFORMS

@

1V/ DIVISION
2msecIDlVISION

DISPLAY CIRCUIT BOARD

I
I

SEGMENT DP

~x SEGMENTE
I» SEGMENT

- SEGMENTA
m SEGMENTF-
.4 sEGMENTE' '
a SEGMENTD

I'
I
I
I
I
I
I
I
I
I
I
I
I
l
I
I

V 107 V10

mu I-aas man-a

0104
Ame-63:5

Q10

C 4st

.---------------------------------.3T------N