Heathkit Service Bulletins - HD-4040 (Revised & Complete)
Joseph W Lutz
joelutz at JUNO.COM
Wed Jan 21 00:51:06 EST 1998
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-1
Can't Set Demodulator To 1700 HZ Tone
Check the 16-pin IC plugs at U30 and U34 for being interchanged.
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July 5, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-2
Schematic Corrections - R49 And T1
On the schematic in the Hd-4040 Assembly manual [PN 595-3334] and the
HD-4040 Blue Book, make the following schematic corrections:
Change R49 from a 10 kilohm resistor to a 4700 ohm resistor.
At T1 on the yellow schematic, change the transformer part number
from 54-1040 to 54-1045.
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July 19, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-3
"HDLC can't INIT" Error Message Displayed
The HDLC will not initialize the HBAUD parameter to either 300 or 400
baud and perm it to NOVRAM. An error message immediately appears on the
screen saying "HDLC can't INIT."
A temporary solution is to override the firmware by placing the TNC in
the transmit mode or by having the TNC identify in CW immediately
following the PERM command. This will clear the error message and the TNC
will operate properly.
Future production should have a firmware change to correct this problem.
Because of the low complaint rate [0.1%] and low inventory, an insert
won't be put into the finished goods stock.
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August 30, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-4
Blue Book Correction - Alignment
In the HD-4040 Service Data Manual [Blue Book], make the following
correction:
Alignment, page 8-10, step 6.
Change "R33" to "R31". R31 nulls the audio signal at TP1.
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August 30, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-5
Blue Book Correction - Block Diagram
In the HD-4040 Blue Book, Circuit Description, page 5-2, the names of the
system bus data line and the system bus contreol line are interchanged on
the block diagram.
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October 25, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-6
Firmware Updated
The Version 3.2 code in ROMs U9, U10, U11 and U12 has been updated to
Version 3.3. This updated code allows the HDLC to intialize the HBAUD
parameter to either 300 or 400 baud and perm it to NOVRAM [SEE Bulletin
No: HD-4040-3]. Also, the Version 3.3 code allows 10 retry attempts
before disconecting. In future production of the HD-4040, the following
ROM changes will occur.
U9 from a #444-349-1 to a #444-349-2
U10 from a #444-350-1 to a #444-350-2
U11 from a #444-351-1 to a #444-351-2
U12 from a #444-352-1 to a #444-352-2
If replacement of a ROM is needed, all four ROMs will have to be the same
version.
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December 20, 1985
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-7
Blue Book Corrections - Schematic
In the HD-4040 Service Date manual [Blue Book], make the following
schematic corrections.
Change:
R49 from 10 kilohm resistor to 4700 ohm resistor.
R63 at pin 5 of U20B to read R69.
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June 13, 1986
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-8
Can't Store Data In Optional RAM at U8
With the present firmware used in the TNC, the CPU will not recognize the
RAM installed at U8 without special programming. A 4K gap exists between
the AM at U7 and the optional RAM at U8. At the present time, this is
considerednormal operation. Product Management has been informed of this
situation.
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August 8, 1986
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-9
HD-4040 TNC To HW-6502 Interconnect Cable
Here's an interconnect cable to use to operate the HD-4040 TNC with the
HW-6502 Transceiver:
Drawing shows [1] COAX cable, center conductor, from the HW-6502 mic
plug to J3 connector of the HD-4040 [pin 5/MIC]. A jumper from the
center conductor of this cable to a 4.7K ohm resistor and then to the J3
connector [pin 4/PTT].
Another COAX cable, center conductor, runs from the HW-6502 earphone
plug to J3 connector [pin 3/REC]. The shield of this cable runs to J3
[pin 6/GND].
Note: The two coax outer shields are connected together.
[[If anyone is in dire need of the drawing before I can scan it in,
please let me know and I will send them a copy of it]].
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March 31, 1988
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-10
HD-4040 TNC To HW-2/XL and HW-4/XL Interconnect Cable
Here's an interconnect cable to use to operate the HD-4040 TNC with the
HW-2, HW-2XL, HW-4 and HW-4XL Transceivers:
Drawing shows [1] COAX cable, center conductor, from the HW-units mic
plug to a .1 uF capacitor then to the J3 connector of the HD-4040 [pin
5/MIC]. A jumper from the center conductor of this cable to a 20K ohm
resistor and then to the J3 connector [pin 4/PTT].
Another COAX cable, center conductor, runs from the HW-units earphone
plug to J3 connector [pin 3/REC]. The shield of this cable runs to J3
[pin 6/GND].
Note: The two coax outer shields are connected together.
[[If anyone is in dire need of the drawing before I can scan it in,
please let me know and I will send them a copy of it]].
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October 27, 1989
HD-4040 Bulletin No:
Terminal Node Controller HD-4040-11
Remote Console As A Terminal
In order for the HD-4040 TNC to operate properly with the ET-19-2 Remote
Console, set the Remote Console's "SCROLL DELAY" to OFF and the BAUD RATE
to 300 baud.
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Thats everything I hold up to 1989 that covers the HD-4040. Enjoy!
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73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
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