Hallicrafters SX-117 Operating instructions

1
WDØGOF Walt Cates

2

3
HALLICRAFTERS
SX-117
REPAIR MANUAL
THIS DOCUMENT IS DESIGNED TO BE A COMPANION DOCUMENT TO THE
HALLICRAFTERS OPERATING AND SERVICE INSTRUCTIONS
COMMUNICATION RECEIVER MODEL SX-117 MANUAL
Walter Cates, WDØGOF

4
ACKNOWLEDGEMENTS
Many thanks to Jim, K9AXN and Al, W8UT
who loaned me SX-117’s
for the 4 months it took to write this document

5
TABLE OF CONTENTS
1, INTRODUCTION .............................................................................................................................................................................7
2, GETTING STARTED .........................................................................................................................................................................8
2-1, MANUAL STRUCTURE .....................................................................................................................................................................8
2-2, PRODUCTION RUN..........................................................................................................................................................................8
2-3, TEST EQUIPMENT............................................................................................................................................................................8
2-3-1, SIGNAL GENERATOR ...............................................................................................................................................................8
2-3-2, AUDIO POWER METER............................................................................................................................................................9
2-3-3, OSCILLOSCOPE ......................................................................................................................................................................10
2-3-4, FREQUENCY COUNTER..........................................................................................................................................................10
2-3-5, TEST METER ..........................................................................................................................................................................10
2-3-5-1, RF BLOCKING PROBE...........................................................................................................................................................................10
2-3-6, AUDIO OSCILLATOR...............................................................................................................................................................11
2-3-7, CAPACITIVE TUBE PICKUP .....................................................................................................................................................11
3, PRELIMINARY INSPECTION ..........................................................................................................................................................12
3-1, VISUAL/MECHANICAL INSPECTION...............................................................................................................................................12
3-2, RECAP ...........................................................................................................................................................................................12
3-3, PRODUCTION RUN UPGRADE .......................................................................................................................................................12
4, POWER SUPPLY-TEST AND EVALUATION .....................................................................................................................................13
5, OSCILLATORS-TEST AND EVALUATION.........................................................................................................................................15
5-1, OSCILLATOR DEFINATIONS ...........................................................................................................................................................15
5-2, SSB CRYSTAL OSCILLATOR TEST ....................................................................................................................................................15
5-2-1, SSB OSCILLATOR TEST ...........................................................................................................................................................16
5-2-2, SSB OSCILLATOR SCHEMATIC & VOLTAGE CHART ................................................................................................................16
5-3, MAIN CRYSTAL OSCILLATOR TEST.................................................................................................................................................17
5-3-1, MAIN OSCILLATOR SCHEMATIC & VOLTAGE CHART.............................................................................................................17
5-4, AUXILIARY CRYSTAL OSCILLATOR TEST .........................................................................................................................................18
5-4-1, AUXILIARY OSCILLATOR SCHEMATIC & VOLTAGE CHART .....................................................................................................18
5-5, VFO OSCILLATOR TEST ..................................................................................................................................................................19
5-5-1 VFO SCHEMATIC & VOLTAGE CHART .....................................................................................................................................20
5-6, CRYSTAL CALIBRATOR TEST ..........................................................................................................................................................21
6, RECEIVER TRAIN EVALUATION.....................................................................................................................................................22
6-1 CONTROL SETUP FOR FAULT ANALYSIS..........................................................................................................................................22
6-2, INJECTION LEVEL/SIGNAL TRACING CHART ..................................................................................................................................22
7, SUBSYSTEM TEST AND EVALUATION ...........................................................................................................................................23
7-1, AVC FUNCTION TEST.....................................................................................................................................................................23
7-1-1, AVC TRACKING ......................................................................................................................................................................23
7-1-2, AVC SCHEMATIC & VOLTAGE CHART ....................................................................................................................................24
7-2, S-METER EVALUATION..................................................................................................................................................................25
7-2-1, S-METER SCHEMATIC & VOLTAGE CHART ............................................................................................................................25
7-3, RF AMP SCHEMATIC &VOLTAGE CHART.......................................................................................................................................26
7-4, 50.75 KHZ IF AMP SCHEMATIC &VOLTAGE CHART .......................................................................................................................26
7-5, PRODUCT DETECTOR AND BFO.....................................................................................................................................................27
7-5-1, PRODUCTOR DETECTOR SCHEMATIC & VOLTAGE CHART ....................................................................................................27
7-5-2 BFO TEST & EVALUATION ......................................................................................................................................................27
7-6, 1650 IF AMP SCHEMATIC &VOLTAGE CHART...............................................................................................................................28

6
7-7, SECOND MIXER V5 SCHEMATIC &VOLTAGE CHART .....................................................................................................................28
7-8, 6-MEG IF AMP V4 SCHEMATIC &VOLTAGE CHART .......................................................................................................................29
7-9, FIRST MIXER V2A SCHEMATIC &VOLTAGE CHART........................................................................................................................29
7-10, AUDIO AMP AND OUTPUT V12A &BSCHEMATIC AND VOLTAGE CHART ...................................................................................30
8, PRODUCTION RUN DETERMINATION...........................................................................................................................................31
8-1, CHANGES RUN 1TO RUN 2............................................................................................................................................................31
8-2, CHANGES RUN 2TO RUN 3............................................................................................................................................................31
8-3, CHANGES RUN 3TO RUN 4............................................................................................................................................................31
8-4, CHANGES RUN 4TO RUN 5............................................................................................................................................................31
9, APPENDIX....................................................................................................................................................................................32
9-1 BULLETIN 1964-4 ...........................................................................................................................................................................32
9-2 ENGINEERING CHANGE C15E.........................................................................................................................................................33
9-3 TEST SPECIFICATION ......................................................................................................................................................................34
9-4, SERVICE BULLETIN RUN-5 CHANGE...............................................................................................................................................46
9-5, ENGINEERING CHANGE #C -169....................................................................................................................................................47
9-6, ALTERNATE IF ALIGNMENT...........................................................................................................................................................50
9-7, ALTERNATE PRESELECTOR ALIGNMENT PROCEDURE...................................................................................................................51

7
1, INTRODUCTION
The SX-117 is an amateur radio receiver designed to operate on the HF bands from 80 meters
through 10 meters with option for 10MHz WWV. Operation on LF band can be achieved with
the companion accessory, the HA-10 converter. Its design was finalized in 1961 and was in
production from 1962 through 1964. The average cost through its production years was
$395.95. It has been referred to as the poor man’s SX-115, this is a big mistake. The SX-115 cost
ran $599.50. The electrical designs are quite similar. The design of the VFO in the SX117 is
significantly more stable eliminating the need for a VR regulator tube. The SX117 uses more dual
tubes so the active tube stage count for the 117 is 22 and for the 115 it is 21. A good part of the
cost difference was the production cost. The mechanical design of the 115 was expensive and
complicated. Because of the improved mechanical design, from an owner’s standpoint the SX-
117 is much simpler to maintain. So overall, in my mind the SX-115 gets a *** rating and the
SX117 gets ****.
If you compare the specifications, point for point you find the SX-115 and the SX117 are very
much the same. If you compare the actual performance the SX-117 Is much better. The S+N:N
spec for both radios is the same, SSB, ½ microvolt for 10db s+n:n. The 115 commonly runs 12 to
15db. The 117 commonly runs 18 to 24db. The AVC figure of merit for the 115 is no more than
10db audio change over an input signal change of 60db. The 115 demonstrates 5 to 8db change
in audio over 60db which is very good. However, the 117 spec states 5db over an 80db range.
The 117 demonstrates ¾ to 1db over 80db which is outstanding. When you combine the better
signal to noise ratio with the superior AVC performance you have a quiet, comfortable copy of
the HF bands.

8
2, GETTING STARTED
2-1, MANUAL STRUCTURE
The analysis and troubleshooting procedures are sequenced in a specific manner to minimize
back tracking.
Section 2-3, Test equipment requirements defined
Section 3, Cleaning, recapping and visual inspection.
Section 4, Verify the power source.
Section 5, The oscillators tested and verified.
Section 6, The receiver train signal tracing.
Section 7’ Simplified schematics and voltage charts
--Section 7-1, AVC circuit performance.
--Section 7-2 through 7-10, Subsystem troubleshooting and voltage charts.
Section 8, Production run determination
Section 9, APPENDIX
2-2, PRODUCTION RUN
Prior to any maintenance activity you need to determine which production run your rig is.
Refer to section 8, to make this determination. You should make upgrade changes to your rig
before starting the maintenance activity. It is highly recommended to upgrade to at least level
C (production run 3). BE AWARE: The voltage and signal levels in all of the subsystem charts
apply to production run 3 and above radios. Unmodified run 1 and run 2 radios will vary
greatly.
2-3, TEST EQUIPMENT
There is no need for expensive or elaborate test equipment. I purposefully minimized the test
equipment I used to develop this document.
2-3-1, SIGNAL GENERATOR
The signal generator needs to cover, minimum, 50KHz to 30MHz. The key feature is a
calibrated output. The output should be metered with a step attenuator, and capable of
precise output from 0.1uv to 100kuv. For the development of this document, I used the
URM25-D.

9
2-3-2, AUDIO POWER METER
An audio output meter such as the General Radio 1840A (my choice) is all that is needed.
There are many that are up to the task. The key features are: Internal variable load (at least 3
ohms to 1.5k), variable full-scale power, 2mw to 20w and a meter calibrated in watts and DB.
Fully self-contained no power no batteries. The majority of the receiver test specs involve a fixed
signal input and a minimum or fixed audio output across a fixed load. Other specs involve a
change in audio output across a given load due to a change in input signal. All of these
measurement requirements are satisfied by a good audio power meter.
For my bench setup I have a standard ¼ inch phone plug which goes to a switch. The switch
selects either a speaker or the audio power meter. Like the SX-117 most of the equipment I work
on (Hallicrafters SR series) has a front panel phone jack that disconnects internal speakers. I
have an adaptor phone jack with clip leads for working on various other radios. A side benefit
of using an audio power meter with built in load is, you do not have to listen to the constant
drone of the receiver. Switching in the speaker allows you to quickly find the signal when you
change frequencies.

10
2-3-3, OSCILLOSCOPE
You will need to accurately measure DC levels as well as AC and RF signals. I used a Hantek
DSO5102 to develop this document ($219 @ amazon). This is not an endorsement of Hantek. I
got it because I had never used a digital scope and it was inexpensive. What I like about a
digital scope is all the information presented on the screen; frequency, period, mean voltage,
peak to peak voltage, signal minimum, signal maximum, pulse width, rise time and a myriad of
other features I have yet to explore.
2-3-4, FREQUENCY COUNTER
You need a range of 50KHz through 30MHz.
2-3-5, TEST METER
Here you can save a little money. Nothing in the SX-117 (or most of the vintage receivers of
the era) requires measurements of the four digit or better accuracy. The $4.00 on sale DVM at
Harbor Freight is perfect. Just be sure you get the one with the 1000vdc scale.
2-3-5-1, RF BLOCKING PROBE
These inexpensive meters work fine unless you are trying to measure a dc voltage with RF
present, like the plate, grid or cathode of an oscillator or mixer. It is simple to make an RF
blocking probe for an inexpensive meter. Install a 270uh –1mh choke in the barrel of a dc
probe. It will work with oscillators and low power mixers. Don’t go messing about in the PA of
a transmitter with one.
`

11
2-3-6, AUDIO OSCILLATOR
Be careful here. Most function generators will not work. Most function generators are 50-ohm
output, you need 600 ohms. Most function generators are limited to 10 to 20vpp output. You
need at least 50vpp. I used a WAVEFORMS 401B for the development of this document. The
old HP 200 series are great and inexpensive.
2-3-7, CAPACITIVE TUBE PICKUP
The capacitive pickup tool is a metal sleeve that slides over a tube to sample any RF present. It
is used most commonly to sample oscillator, driver and mixer signals without presenting a load
to the circuit. It fits snuggly over the tube without contacting the chassis. The most common
method of construction is the cut the base off a tube shield. It will be used to test the BFO or
any oscillator you choose.

12
3, PRELIMINARY INSPECTION
3-1, VISUAL/MECHANICAL INSPECTION
Now is the time for a very intensive inspection for broken or burned parts. A thorough
cleaning of the chassis, controls and drive trains.
For details see: https://wd0gof.files.wordpress.com/2019/02/rig-cleaning.pdf.
3-2, RECAP
There are two must replace capacitors in the SX-117. One is the three-section filter capacitor
C117A, B &C. The other is the cathode bypass capacitor for V12B, C98, 25uf 25v.
There are differing opinions about paper capacitors. If you are in the camp that always replaces
paper caps, there are five of them, C107, C108, C109, C110 and C111.
3-3, PRODUCTION RUN UPGRADE
Refer to section 8 and determine which of the upgrades you want to include and make those
modifications before starting fault isolation process.

13
4, POWER SUPPLY-TEST AND EVALUATION
The power supply for the SX-117 was designed to operate on 105 to 125vac, 50/60Hz.The
power consumption at 117vac is projected to be 70 watts. There are two secondary windings
on the power transformer, the filament and the B+ windings. The center tapped B+ winding
feeds a full wave rectifier that produces a raw 200vdc which is filtered to produce the nominal
168vdc primary B+ supply. Via R90 (10K) a secondary B+ is produced which feeds the audio
detectors and audio preamp. A third auxiliary B+ supply Is produced by R-57 that provides the
screen voltage for the 3rd IF amp V9 and the B+ for the 100KHz oscillator if installed.
The following chart provides the power supply measurement of an SX-117 that functions
properly and meets all specifications. It should be noted that the power supplies in equipment
of this era were subject to quite a wide variance in actual operating voltages. Variations of +/-
10% are common. These measurements were recorded with the bench supply running 123.5vac
and the equipment was drawing 0.58amps.
DESCRIPTION
TEST POINT
DC COMPONENT
AC RIPPLE
B+ Secondary
(Measurements taken using a
scope)
Anode CR3 to center tap
///////////////
530vpp
Anode CR4 to center tap
////////////////
530vpp
Raw rectified power.
JUNCTION OF CR3, CR4 AND R89
230vdc
30vpp
INPUT SIDE OF PI FILTER
JUNCTION OF C117B AND R91
227VDC
10vpp
PRIMARY B+ SUPPLY
JUNCTION OF C117C AND R91
179VDC
0.200vpp
SECONDARY B+ SUPPLY
JUNCTION OF C117A AND R90
153VDC
0.01vpp
AUXILIARY B+ SUPPLY
JUNCTION OF R57 AND T7 PIN3
168VDC CAL osc off
163VDC CAL osc on
0.200vpp

14
Voltage patten seen on anodes of CR3 and CR4. Pattern is identical on both anodes.

15
5, OSCILLATORS-TEST AND EVALUATION
The normal operation of everything in the receiver train from T1 through the BFO is dependent upon the
oscillators being on frequency. This fact cannot be over stated. Extra effort getting the oscillators right will be
rewarded by better than average performance of the equipment.
Power up the equipment and allow 30 minutes warm up. All the crystal oscillators will be tested
first to allow maximum time for the VFO to stabilize. Set all SX-117 controls as follows:
The following settings will be Standard for all oscillator testing.
RF GAIN –min.
XTAL SELECTOR –NORMAL.
PRESELECTOR –doesn’t matter (dm).
BAND SELECTOR –80 meters.
CAL RESET –ON INDEX MARK.
NL/CAL –off.
FUNCTION –LSB
SELECTIVITY –dm
NOTCH FREQ. –dm
AF GAIN –Min
5-1, OSCILLATOR DEFINITIONS
In the equipment specification and in the system schematic there are 2 oscillators referred to
as the CRYSTAL OSCILLATOR. They are V3 crystal oscillator and V13A crystal oscillator. For the
purpose of this document V3 will be referred to as the main crystal oscillator. V13A will be
referred to as the aux crystal oscillator.
5-2, SSB CRYSTAL OSCILLATOR TEST
The SSB oscillator has no adjustments to pull the xtals on frequency. The original xtals came in
matched pairs. Sets of matched pairs are no longer available (The exact difference of 100KHz
between the USB and LSB xtals will affect the BFO adjustments to be done later). The original designer’s
view was that if it was off frequency, you replaced the crystals with a new matched pair. Today
your options are limited and you may have to get creative. If both xtals are low or high you can
change the values of C58 and C59 to pull the xtals up or down. Changing the tube will also pull
the xtal frequency. The goal, and important factor is the USB to LSB difference (1700KHz –
1600KHz = 100KHz). If the xtal frequencies are off, but the difference is 100KHz the error can
be offset by the VFO CAL RESET and you can still get a zero beat on USB and LSB. Read section
6-11 in the Hallicrafters OPERATING AND SERVICE INSTRUCTIONS manual.

16
5-2-1, SSB OSCILLATOR TEST
Power up in the configuration listed above. Connect the scope using a 10X probe to pin 7 of
V8. You should see a minimum of 5.0 vpp. Move the probe from the scope to the frequency
counter. You should read 1600KHz. Switch from LSB to USB. You should read 1700KHz on the
counter. Move the probe from the counter to the scope. You should see a minimum of 5.0
vpp. The amplitude of the signals on USB and LSB should be equal. Slight offset errors can be
corrected by the VFO CAL RESET; however, you will be required to readjust the CAL RESET each
time you change bands.
5-2-2, SSB OSCILLATOR SCHEMATIC & VOLTAGE CHART
PIN #
1
2
3
4
5
6
7
8
9
V8A
//////////
0
110
6.3vac
0
124
4.0
//////////
//////////
V8B
172
//////////
//////////
//////////
//////////
//////////
//////////
0.3
0
VOLTAGES ARE DC UNLESS OTHERWISE NOTED. You will need an RF blocking probe.

17
5-3, MAIN CRYSTAL OSCILLATOR TEST
Each of the crystals in the oscillator has an adjustment. This adjustment affects both the
amplitude and the frequency of the oscillator output.
1, With the controls set per paragraph 5, and the equipment warmed up, connect a cable
from the scope to J4 (CRYSTAL OSC OUTPUT). Adjust L10B for max peak to peak voltage. Record
the peak to peak voltage. Move the cable from the scope to the frequency counter. Readjust
L10B for 10.000MHZ. Move the probe back to the scope observe the signal. If you have not lost
more than 10% of the peak to peak voltage that setting is good. Minimum signal level is 1.0 vpp.
NOTE: Arbitration of signal amplitude and frequency for each crystal in this oscillator may be required. If possible, go with the most accurate
frequency rather than peak output voltage. The CAL RESET function of the VFO can offset up to +/- 1500Hz. Ideally you would adjust for exact
frequency. But unless you have a lot of spare xtals this is impractical.
2, If the WWV xtal is installed turn the BAND SELECTOR to the WWV position repeat the
process in step 1 above adjusting L14.
3, Set the band switch to 7.0 and repeat the process in step 1 above adjusting L11B.
4, Set the band switch to 14.0 and repeat the process in step 1 above adjusting L13B.
5, Set the band switch to 21.0 and repeat the process in step 1 above adjusting L12B.
6, If xtal is installed set the band switch to 28.0 and repeat the process in step 1 above
adjusting L10A.
7, Set the band switch to 28.5 and repeat the process in step 1 above adjusting L11A.
8, If the xtal is installed set the band switch to 29.0 and repeat the process in step 1
above adjusting L12A.
9, If the xtal is installed set the band switch to 29.5 and repeat the process in step 1
above adjusting L13A.
5-3-1, MAIN OSCILLATOR SCHEMATIC & VOLTAGE CHART
PIN #
1
2
3
4
5
6
7
8
9
VOLTAGE
170
0
1.3
6.3vac
6.3vac
170
0
1.0
0
ALL VOLTAGES ARE DC UNLESS OTHERWISE NOTED. You will need an RF blocking probe.

18
5-4, AUXILIARY CRYSTAL OSCILLATOR TEST
The following assumes the normal configuration, that is without any axillary crystals installed.
This procedure is an optional operation. The object is to prove the operation of the auxiliary
even though it is most likely not in use. If the auxiliary sockets are populated select each
installed crystal in order and perform steps c through g. Otherwise:
a, Pull the 80-meter crystal, Y8 and install in auxiliary socket 1.
b, Set the XTAL SELECTOR switch to position 1
c, Power up, any mode. RF and AF GAIN at min.
d, Connect scope probe to the junction of C57 and the terminal strip.
e, The signal level should be 10vpp.
f, Move the probe from the scope to the frequency counter.
g, it should read the crystal frequency.
5-4-1, AUXILIARY OSCILLATOR SCHEMATIC & VOLTAGE CHART
PIN #
1
2
3
4
5
6
7
8
9
VOLTAGE
170
0
130
6.3vac
0
55
2.0
33
47
Measurements taken with 80-meter xtal plugged into Aux socket 1 and XTAL SELECTOR in position 1. Switch the OFF/NL/CAL switch
to the CAL position, tune for a zero beat to ensure the aux oscillator is working. You will need an RF blocking probe.

19
5-5, VFO OSCILLATOR TEST
NOTE: If the C15f to C127 mod has not been installed see APPENDIX 9-2 for
instructions and complete the modification before proceeding.
The following procedure is a substitute for the VFO alignment and adjustment found in
sections 6-8 and 6-9 of the Hallicrafters OPERATING AND SERVICE INSTRUCTIONS manual.
SETUP:
Connect frequency counter to pin 8 of V6 or J5.
Preset C127 to the center of its tuning range.
CAL RESET to center of its rotation.
Turn the FUNCTION switch to any mode.
Allow 30 minutes warm-up/stabilize time.
INITIAL PRESET.
Tune the main tuning dial to 300.
Adjust L16 for a reading of 4.550MHz on the frequency counter.
TRACKING ALIGNMENT.
Tune the main tuning to 100 and adjust C127 for 4.750MHz on the counter.
Tune the main tuning to 400 and adjust L16 for 4.450MHz on the counter.
NOTE: These two adjustments interact, you may have to go back and
forth several times, under or over correction at one or the other end
to get both ends correct. +/- 500 is good, right on is best
FINAL CHECK
MAIN TUNING FREQUENCY
04.850MHz
100 4.750MHz
200 4.650MHz
300 4.550MHz
400 4.450MHz
500 4.350MHz

20
5-5-1 VFO SCHEMATIC & VOLTAGE CHART
PIN
1
2
3
4
5
6
7
8
9
VOLTAGE
164
1.2
150
0
6.3vac
155
0.2
31
24.6
ALL VOLTAGES ARE DC UNLESS OTHERWISE NOTED. You will need an RF blocking probe. It will be helpful if you switch on the CAL oscillator and
tune for a good tone in the speaker. If your RF blocking probe is working correctly you may shift the frequency of the tone a little, but it will not
kill the oscillator. If the tone goes away completely then you need to find a better blocking probe.