Heathkit Service Bulletins - HD-1410 (Revised & Complete)

Joseph W Lutz joelutz at JUNO.COM
Tue Jan 20 13:39:24 EST 1998


                        April 17, 1975
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-1

                 Modifications For Use With Ten-Tec, Triton And
                      Rigs With Similar Keying Requirements

It has been found that the Ten-Tec Argonaut and Triton keyin circuits
require that the key-line be brought to within a few tenths of a volt of
ground to operate properly,  Either of the following modifications to the
HD-1410 will allow it to be used with the above units:

A.  If the Hd-1410 is to be used exclusively with the Ten-Tec or rigs
with similar            requirements, R27 and D5 can be replaced with
jumper wires.  This disables            Q7 and eliminates the .7 volt
drop due to D5.

B. If the HD-1410 is to be used both with such rigs and cathode or grid
block keyed      rigs, the modification shown on the attached schematic
may be made.  The jack      labelled " Ext. Key" becomes a secondary
"keyer-out" jack for use only with           rigs employing a positive
key line, and solid state keying circuit.

1.  Refer to page 40 of assembly manual and remove the wire between jack
L, lug        1 [Keyout Jack] and circuit board hole F.

2.  Disconnect the remaining wire from jack L, lug 1 and connect to
circuit board           hole F.

3.  Mount terminal strip and components as shown:

    [[Shows TS 431-62 To be mounted under top screw of Jack L and bent
down slightly.   Connect a  4700 Ohm resistor between lugs 1 and 3 of TS
431-62.  Connect base of [PN 417-801] to lug1 of TS 431-62; emitter to
one lug of Jack L and the collector to the other Jack L lug]]

4.  Connect wire from Lug 3 of Terminal Strip to junction of R23 and R26
on circuit       board.  Solder this wire to lead of R26.

                                        Keyer Keys Continuously Or
Erratically

Problems with RF causing the keyer to key continuously or erratically,
particularly when using long wire or random length antenna systems, can
be eliminated by connecting a .001 uF disc ceramic across the keyer
output jack.

                                                       Intermittent
Sidetone

In some units, if the "tone" control is turned fully clockwise [low
frequency end], the sidetone will be intermittent.  Turning the pot
slightly counterclockwise will eliminate the condition.
-------------------------------------------------------------------------------------------------------------------
                        May 20, 1975
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-2

                        Service Guide

The following is a step by step procedure for servicing the HD-1410
Keyer:

Equipment Needed:

        1 VTVM [Not a VOM or DVM]

        Set controls on HD-1410 as follows:

        AC Switch - ON
        Speed - Full CCW
        Volume - 1/4 CW

        Set VTVM as follows:

        To read DC + Voltage

                                C A U T I O N

When making voltage checks in the unit, be very careful where the probe
is touched as 110V AC voltage is present also.

1.  The first test is to check the DC voltages for the power supply and
pass                  transistor Q8.  If any deficiencies are found in
this area, they must be corrected       before proceeding on.

2.  The most important section in the keyer is the Dot Generator and Dash
Divider,        this will be checked as follows:

        With the keyer shut off, connect a jumper wire from pin 8 of IC1D
to ground.  With the keyer set up in this manner, both the dot generator
and dash divider can be checked at the same time without pushing the
paddles.  Turn the keyer on.  Connect the ground lead of the VTVM to the
chassis of the keyer.

        A. Set the VTVM to a 1.5VDC range and touch the probe to pin 10
of IC2D.
The meter should read about  .16 and the needle should be oscillating
slightly.  If these results are not obtained, check  Q1, Q2, C3, D1 and
speed control.

        B.  Set the  VTVM read +5VDC range and touch meter probe to pin 5
of IC4A.  Reading shuld be  .16VDC  with needle oscillating slightly.
Check  D3 and  R12, if proper results are not obtained.

        C.  Touch meter probe to pin 8 of IC4A.  Meter needle should
oscillate rapidly between 1.5 and 2.5VDC.  If proper results are not
obtained, first check pin 2 of IC4A.  Meter needle should oscillate
between 3.6 to 4VDC at half the rate of pin
8.  Replace IC-4, if necessary.

        D.  Touch meter probe to pin13 of IC4B.  Meter needle should
oscillate between . 5 and 3.5VDC at 1/2 the rate of test C above.  If
proper results are not
obtained, check pins 14 and 3 of IC-4 for 5VDC.  Replace IC-4, if
necessary.

        E.  Touch the meter probe to pin 12 of IC3C.  Meter needle should
oscillate from 1.6 TO 3.4VDC.  If proper results are not obtained, check
pin 13 of
IC3C for 5VDC.  Replace IC3C, if necessary.

3.  Output circuitry:  Since the jumper is already installed in the bit
generator and    dashes are being produced, we'll use this same approach
for checking the output circuitry.

        A.  Touch the meter probe to the  [C] of Q4.  Meter needle should
swing between .2VDC and 2.8VDC.  If proper results are not obtained,
check
resistor R24.  Replace Q4.

        B.  Touch the meter probe to the [C] of Q5.  Meter needle should
oscillate between .3VDC and .8VDC.  If proper results are not obtained,
check R25. Replace Q5.

        C.  Touch meter probe to point [J] or keyer output jack.  Meter
needle should oscillate from .3VDC to .8VDC.  If proper results are not
obtained,
check or replace D4.

        D.  Repeat the same procedure for Q6, Q7 and D5.

4.  Tone oscillator circuit.  Jumper will still be connected to pin 8 of
IC1D.

        A.  Touch meter probe to pin 4 of IC5D.  Needle should oscillate
between .6 and 1.4VDC.  If proper results are not obtained, check C5, C6,
tone control.  Replace IC-5.

        B.  Touch meter probe to [C] of Q3.  Meter needle should
oscillate
between 4.3 and 4.7VDC.  If proper results are not obtained, check C7,
R21.  Replace  Q3.

5.  Paddle control and memory logic:  Shut off the keyer and unsolder the
jumper wire from pin 8 of IC1D.

        A.  Turn the keyer on and with the VTVM check the logic levels
for IC-1, IC-2 and IC-3 as shown on the schematic.  With both paddles
released the logic levels will be reversed.

        B.  Memory bit problems can only be in IC-5, R3, R4, C1 and C2.
------------------------------------------------------------------------------------------------------------------
                        May 20, 1975
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-3

                       Keyer Keys Continuously Or Erratically

In the next run, a .005MFD [5000pF, PN 21-57] will be added across the
Keyer output jack.

This supersedes the information in Bulletin No: HD-1410-1
-------------------------------------------------------------------------------------------------------------------                             MARCH
26, 1976
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-4

                                   No Dots Or Dashes

If the unit has no dots or dashes output, but has a tone in the "hold"
mode, check the installation of Q2.  The customer apparenly tries to
twist the transistor so that the flat of the transistor will align with
the flat screened on the board.  This will cause the base & collector
leads to short.

The manual is being changed to clarify the installation of this
transistor.
-------------------------------------------------------------------------------------------------------------------
                        JUNE 24, 1976
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-5

                                  RFI

RFI in the keyer coming through the power supply can be eliminated by
installing two .005UFD/1.6KV capacitors [PN 21-44] across the AC line to
the ground.
--------------------------------------------------------------------------------------------------------------------
                        July 9, 1976
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-6

                        Wrong Type Of Round Knob

Some kits were shipped with round knobs [PN 462-932] that will not accept
the knob bushing.  Although these knobs will fit onto the control shafts,
the knob pointer may not align properly.
-------------------------------------------------------------------------------------------------------------------
                        September 23, 1977
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-7

                             Keyer Locks On Some Bands

++++Info not yet available++++
-------------------------------------------------------------------------------------------------------------------
                        July 24, 1978
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-8

                 No Dashes; Tone And Dots Okay

Check for a possible foil bridge between pins 8 and 9 or between pin 8
and ground of the Dash Reset circuit, IC2 [PN 443-1].  The bridge is
usually too small to see without a magnifier.  The bridge usually can be
removed by scraping the area around pins 8 and 9 with a knife or other
similar object.
------------------------------------------------------------------------------------------------------------------
                        May 8, 1980
HD-1410                                         Bulletin No:
Electronic Keyer                                        HD-1410-9

                            Sidetone Not Loud Enough

++++Info not yet available++++
--------------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1989 that covers the HD-1410. Enjoy!
--------------------------------------------------------------------------------------------------------------------


73 de Joe  W7LPF/4  [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]

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