Heathkit HX 1681 Schematic

Page 1

C-IRCUIT

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NOTES:

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. I ---T
SC H EM ATIC O F THE Part of 595-2240 5 I m a" N 33;. .L. ° E. E : 2°
H E AT HK IT ® ('5'") I :1: +1 7014 O ELK '0 H I 2 "N 0 12v nzcuuron 51.35%. I :
Copyright © 1979 t = PSVTI'ESR 5: 3 vzsov our. °' 271? 0408 0 £7.12; Um:
I 3 9 (4)57_27 N 2470 R435 ---J
CW TRANSMITTER HeathCompany oaoov RED 1_ _L N
All Rights Reserved MC. 3 7 5 m 2333"; L 3}" pm 55°
MODEL PIX-1681 Primed Inme Unhed smIIIoIAmaIIuI 1233 '
no I 2: :37 can =_ 50:21 _:
0291101 43370 _ OzI-1222_ ' l

1. COMPONENT NUMBERS ARE IN THE FOLLOWING GROUPS.

1-99
100-199
200-299
300-399
400-499
500-5?9
600-699

PARTS MOUNTED ON THE CHASSIS.

ARTS MOUNTED ON THE HFO/MIXER CIRCUIT BOARD.
PARTS MOUNTED ON THE VFO CIRCUIT BOARD.

PARTS MOUNTED ON THE DRIVER CIRCUIT BOARD.

PARTS MOUNTED ON THE POWER SUPPLY CIRCUIT BOARD.

PARTS MOUNTED ON THE ANTENNA SWITCH CIRCUIT BOARD.

PARTS MOUNTED ON THE OUTPUT FILTER CIRCUIT BOARD.

2. ALL RESISTORS ARE l/4-WATT, 511 TOLERANCE. UNLESS OTHERWISE
NOTED. RESISTOR VALUES ARE IN OHMS IK-lODD).(M-1.DD0.000I.

3. CAPACITORS LESS THAN 1 ARE IN uF (MICROFARADSI. ALL OTHER
CAPACITORS ARE IN pF (PICOFARADS) UNLESS OTHERWISE NOTED.
4. ARROWS AT CONTROLS INDICATE CLOCKWISE ROTATION AS

VIEWED FROM THE SHAFT END OF THE CONTROL.

\n

. 0 THIS SYMBOL INDICATES A DC VOLTAGE 121051 MEASURED WITH A

HIGH-INPUT IMPEDANCE VOLTMETER FROM THE POINT INDICATED
T0 CHASSIS GROUND UNDER THE FOLLOWING CONDITIONS.

A. THE TRANSMITTER IS UNKEYED.

B. MODE SWITCH IN THE XMIT POSITION.

_ E THIS SYMBOL INDICATES A DC VOLTAGEJthI-I MEASURED AS IN

V

STEP 5, UNDER THE FOLLOWING CONDITIONS.

TRANSMITTER KEYED 0R
MODE SWITCH IN THE TUNE POSITION.

THIS SYMBOL INDICATES A ClRCUIT BOARD GROUND.

THIS SYMBOL INDICATES A CHASSIS GROUND.

THIS SYMBOL INDICATES A CHASSIS~MOUNTED PART, SHOWN
ON A CIRCUIT BOARD.

10. [3 THIS SYMBOL INDICATES A ClRCUIT BOARD WIRED CONNECTION.

ll. <6 THIS SYMBOL INDICATES AN EDGE-MOUNTED CIRCUIT BOARD

CONNECTION.

12-oII°o

ONLY DURING ALIGNMENT.

THIS SYMBOL, SHOWN ON THE HFOIMIXER CIRCUIT BOARD,
INDICATES A TEMPORARILY MOUNTED CAPACITOR USED

13. -L* REPLACE CAPACITORS ONLY WITH HEATHKIT PART NUMBERS
T SHOWN.
14. REFER TO THE "CIRCUIT BOARD X~RAY VIEWS" FOR THE

PHYSICAL LOCATION OF PARTS.

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Page 2

NOTES:

1.

SCHEMATIC or THE
HEATHKIT®

CW TRANSMITTER
MODEL HX-1681

COMPONENT NUMBERS ARE IN THE FOLLOWING GROUPS.

1-99
100-199
200-299
300-399
400-499
500-599
600-699

PARTS MOUNTED ON THE CHASSIS.

ARTS MOUNTED ON THE HFO/MIXER CIRCUIT BOARD.
PARTS MOUNTED ON THE VFO CIRCUIT BOARD.

PARTS MOUNTED ON THE DRIVER CIRCUIT BOARD.

PARTS MOUNTED ON THE POWER SUPPLY CIRCUIT BOARD.

PARTS MOUNTED ON THE ANTENNA SWITCH CIRCUIT BOARD.

PARTS MOUNTED ON THE OUTPUT FILTER CIRCUIT BOARD.

ALL RESISTORS ARE l/4-WATT 5% TOLERANCE, UNLESS OTHERWISE
NOTED. RESISTOR VALUES ARE IN OHMS (K-1000I,IM-1.000,000I,

CAPACITORS LESS THAN 1 ARE IN uF IMICROFARADSI. ALL OTHER
CAPACITORS ARE IN pF IPICOFARADSI UNLESS OTHERWISE NOTED.

ARROWS AT CONTROLS INDICATE CLOCKWISE ROTATION AS
VIEWED FROM THE SHAFT END OF THE CONTROL.

mg...
[IASU I
Part of 595-2240 fl 5:: as
(man, .92 I T 7" SW3
Comm @1979
Heath Company

All Rights Reserved
Primed in The United State. of Amun-

m

. 0 THIS SYMBOL INDICATES A DC VOLTAGE [1107.) MEASURED WITH A
HIGH-INPUT IMPEDANCE VOLTMETER FROM THE POINT INDICATED
TO CHASSIS GROUND UNDER THE FOLLOWING CONDITIONS.
A. THE TRANSMITTER IS UNKEYED.
B. MODE SWITCH IN THE XMIT POSITION.

6_ :1 THIS SYMBOL INDICATES A DC VOLTAGEJZIUT-I MEASURED AS IN
STEP 5, UNDER THE FOLLOWING CONDITIONS.
TRANSMITTER KEYED OR
MODE SWITCH IN THE TUNE POSITION.

7. V THIS SYMBOL INDICATES A CIRCUIT BOARD GROUND.
8 E THIS SYMBOL INDICATES A CHASSIS GROUND.
9. THIS SYMBOL INDICATES A CHASSIS-MOUNTED PART, SHOWN

ON A CIRCUIT BOARD.

OFF
= POWERi .

POWER
PB
(a E AR VIE W)

WHT-REI

III-4

it

3 «no», OIIG

X
Bu 9 4
QBOOV RED
uc.° 7 5

_ cu En T

:42 _.
- .02 o

no
.0!
021-701

.02 . T
.ZI-l22_ soov_

10. [3 THIS SYMBOL INDICATES A CIRCUIT BOARD WIRED CONNECTION.

ll. <6 THIS SYMBOL INDICATES AN EDGEEMOUNTED CIRCUIT BOARD
CONNECTION.

12.mfiOTHIS SYMBOL, SHOWN ON THE HFOIMIXER CIRCUIT BOARD.
INDICATES A TEMPORARILY MOUNTED CAPACITOR USED
ONLY DURING ALIGNMENT.

13. J-* REPLACE CAPACITORS ONLV WITH HEATHKIT PART NUMBERS
T SHOWN,
14. REFER To THE "CIRCUIT BOARD X-RAY VIEWS" FOR THE

PHYSICAL LOCATION OF PARTS.