Heathkit ID 1990 Manual

Page 1

HEATHKIT®
J UAL

for the

DIGITAL
BAROMETER
Model ID-1990

595-2355 ,

3.

HEATH COMPANY ° BENTON HARBOR, MICHIGAN

Page 2

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Page 66

l0>P|N
SOCKET

Detail 8-6A

Refer to Pictorial 8-6 (Illustration B ooklet, Page 15) for
the following steps.

( L) Place the chassis inside one of the oven cabinet
halves as shown. Be sure the 9-wire cable is in
the cutout in the end of the cabinet half.

(A) Place the remaining cabinet half on the assem-
bly as shown. Temporarily secure the cabinet
halves together with two sets of 440 X 1-3/8"
hardware (at opposite corners). Be sure the slot
in top cabinet half is on the end of the assembly
that has the cable.

(\/)/Separate the wires at the free end of the 9-wire
cable for 1-1/2 and prepare the ends.

( -/)/ Trim the bare portions of the wires at the free
end of the 9-wire cable to 1/3. Then install a
spring connector on the end of each wire.

Refer to Detail 8-BA and push the spring connectors
into a 10-pin socket as follows:

( 1) Orange wire in hole 1.
[ i) Brown wire in hole 2.
( i) Red wire to hole 3.
( i) Blue wire to hole 4.

( i) Yellow wire to hole 5.

NOTE: Skip hole 6.

( /)1 Gray wire to hole 7.

( {)1 Green wire to hole 8.

( -/) Violet wire to hole 9.
U ) White wire to hole 10

Refer to Pictorial 8-7 for the following steps.

( ) Be sure the line cord of your Barometer is not
plugged in.

[ ) Remove the six screws from the rear panel of
your Barometer. Then remove the rear panel.

( ) Push the 10-pin socket coming from the oven
assembly onto plug P303 0n the analog circuit
board. Be sure the slots in the socket face the top
of your Barometer as shown.

( J Reinstall the rear cover on the Barometer. Use
six 6-32 X 1/4 black screws.

This completes the assembly of your Barometer. Pro-
seed to Calibration.

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Heathkif _

CALIBRATION

If at any time you do not obtain the proper results in
the following steps, refer to the In Case of Difficulty
section of this Manual and correct the problem.

( ] Make sure the oven assembly is connected to
plug P303 on the analog circuit board.

( ) Be sure the INCHES - Mb/kPa slide switch on
the rear panel of your Barometer is at INCHES.
NOTE: The settings of the other switches are not
important at this time.

( ) Refer to Pictorial 9-1 and place a small tape
flag on the non-screwdriver end of the
alignment tool. This will aid you in counting
the number of turns of the tool during calibra-
tion.

Refer to Pictorial 9-2 (Illustration Booklet, Page 17] for
the following steps.

( ) Remove the top cabinet half from the oven as-
sembly. Then use the alignment tool to preset
the three controls in the assembly as follows:

GAIN ADJUST (R219) 25 turns counterclockwise;
then 10 turns clockwise.
(NOTE: This centers the
control in its range].

COARSE ADJUST (R213) 25 turns coun-
terclockwise; then
5 turns clockwise.

FINE ADJUST (R209) 25 turns counterclockwise;
then 10 turns clockwise.

Page 67

FLAG

NON>SCREWDRIVER

/ END

g: F J 'i
ALIGNMENT TOOL

PICTORIAL 9-1

( ] Temporarily set the top cabinet half back onto
the oven assembly. It is not necessary to secure
it with hardware at this time.

( ) Plug the line cord of the Barometer into the
proper AC outlet.

NOTE: The purpose of the calibration hose that you
will use in the following steps, is to cause a change in

pressure that is equivalent to a 2 drop in a mercury
column.

( ) Fill the calibration hose with between 22 and 30
inches of water. Then clamp the hose in the top
calibration clips as shown. Tap the sides of the
hose to remove any air bubbles.

NOTE: Let the temperature inside the oven assembly
stabilize for at least two hours before you continue.

( J 1. Use the alignment tool to adjust the COARSE
ADJUST control (R213) for an indication of
approximately 30.00 on the display:(not criti-
cal at this time). NOTE: Do not remove the
cover from the oven assembly any longer than
necessary.

( ) 2. Set the cover on the oven assembly so the

pressure transducer is exposed (see Pictorial
9»z). '