Hallicrafters SX-117, Repair Manual

Page: 22 / 51

22
6, RECEIVER TRAIN EVALUATION
If you have followed the procedure the power supply system and all the oscillators have been tested and are
fully operational. Now when progressing through the receiver train these items can be eliminated as sources
of faults. This will greatly narrow your focus while analyzing faults.
6-1 CONTROL SETUP FOR FAULT ANALYSIS
Remove V10, ground the tie point of R65 and C82. Power up and allow 5 minutes warm up.
6-2, INJECTION LEVEL/SIGNAL TRACING CHART
INJECTION
FREQUENCY
INJECTION
POINT
GEN.
OUTPUT
PROBE AUDIO
OUT
TEST SUCCESS/FAILURE
IMPLICATIONS TROUBLESHOOT
REF
SECTION
1 1000Hz V12 pin 8 4.5vpp 1x 500mw
Passed, proceed to step 2. Failed, fault in
V12B stage. Check voltages on V12.
7-10
2 1000Hz Input side C94 0.20vpp 1x 500mw
Passed, proceed to step.3. Failed, fault in
V12A stage. Check voltages on V12. Insure
AF gain at max
7-10
3 50.75KHz V11 pin 7 3K uv 1x 200mw
Passed, proceed to step 4. Failed, fault in
V11 stage. Check V11 voltages. Peak the
BFO.
7-5
4 50.75KHz V9 pin1 37k uv 1X 500mw
Passed, proceed to step 5. Failed, fault in V9
or V10. Check tubes voltages. Test continuity
of T7 & T8.
7-5
5 50.75KHz T6 pin 3 6k uv 1X 250mw
Passed, proceed to step 6. Failed, continuity
test l21, R55 and associated passive
components.
--
6 1650KHz V8 pin 2 150k uv 10X 500mw
Passed, proceed to step 7. Failed, fault in
V8A, T5 or T6 or associated passive
components.
5-2-1
7 1650KHz V7 pin 1 200 uv 10X 500mw
Passed, proceed to step 8. Failed, fault in V7,
T4 or associated passive components.
7-6
From this point on, ensure the tuning is peaked
8 6.2MHz V5 pin 7 70 uv 10X 500mw
Passed, proceed to step 9. Failed, fault in V5,
T3 or associated passive components.
7-7
9 6.2MHz V4 pin1 8 uv 10X 500mw
Passed, proceed to step 10. Failed, fault in
V4, T2 or associated passive components.
7-8
10 3.9MHz
Junction of C11
& R5
50 uv 10X 500mw
Passed, proceed to step 12. Failed, fault in
V2A, T1 or associated passive components.
7-9
11 3.9MHz
Junction of S1A-
8 &C4
5 uv 10x 500mw
Passed, proceed to step 13. Failed, fault in
V1, l6, S1 or associated passive components.
Clean S1
7-3
12 3.9MHz J2 0.6 uv Coax 500mw
Passed, proceed to step 14. Failed, fault in
S1, L1A & B, L5, or preselector control.
13
When the radio has successfully passed all tests to this point proceed to AVC FUNCTION TEST section 7-1. Once the AVC is proven to
be functioning properly the radio should be ready for a by the book alignment
. Replace v10 and remove ground from R65.
As indicated above once the AVC is tested and is operational the radio is ready for a by the book alignment.
Section VI of the factory manual contains the procedures for a full alignment. In the factory manual the
procedures in paragraphs 6-4 and 6-6 require additional crystals which may not be available. In section 9-6
and 9-7 of this manual you will find procedures that do not require additional crystals.