Sansui 771 - 5. Troubleshooting Chart; 5-1. Power Supply Troubleshooting; 5-2. Audio Section Troubleshooting; 5-3. Tuner Section Troubleshooting

5.
TROUBLESHOOTING
CHART
5-1.
Troubleshooting
on
Power
Supply
Section
Symptom
Check
Point
1.
No
power
supplied
to
each
section
1-1.
Each
lamp
not
lighted
1.
2
3
4.
5
6.
1-2.
Each
lamp
lighted
1)
+33V
not
supplied
to
emitter
of
TROS
and
+-13.6V
not
supplied
to
emitter
of
TRO6
on
F-14500
Zi
8.
9.
10.
2) +35V not supplied to terminal ((04]) on
F-1499--__— 1,
=
| 13
. Defective TROT, TRO2 on F-1500
3) —35V not supplied to terminal ({12]) on
F-1499 14.
s
16. Defective TRO3, TRO4 on F-1500
4) Normal voltages supplied to each terminal on F-1500 17,
18.
‘19.
20.
5-2. Troubleshooting on Audio Section
1. Quick acting fuse open
1-1. After replacement, fuse open mE
Zz
3. Defective TRO7 (TRO8) on F-1499
1-2. After replacement, fuse not open
1) DC Bias current adjustable ———————————————4.
2) DC Bias current not i ———
6
. Defective TRO5 (TRO6) on F-1499
3) Center voltage adjustable-———-——__—_—_—_—_—__7
4) Center voltage not adjustable
1
11
Cause & What to Do
Imperfect contact of power supply plug
Defective power switch $11
. Imperfect contact of voltage selector
Powet fuse F701 open
. FO5 on F-71500 open
Defective power transformer
FO7, FO8 on F-1500 open
Defective D0O5, DO6 on F-1500
Defective TRO5, TRO6 on F-1500
Defective ZD01, ZD02 on F-1500
FOT, FO2 on F-1500 open
Defective D01, DO4 on F-1500
FO3, FO4 on F-1500 open
Defective D02, DO3 on F-1500
FO6 on F-1500 open
Defective D07, D08 on F-1500
Defective TRO7, TRO8 on F-1500
Defective Relay RY101 on F-1500
Defective TRO1, TRO3 (TRO2, TRO4) on F-1500
Defective TROY, TR11 (TR10, TR12) on F-1499
Set the current to +-19mA by VRO3 (VRO4)
Defective VRO3 (VRO04) on F-1499
Set the center voltage to OV by VRO1(VRO2)
on F-1499
8. Defective TRO1, TRO3 (TRO2, TRO4) on F-1499
9. Defective TRO5 (TRO6) on F-1499
. Defective DO1, DO3 (DO02, DO4) on F-1499
11.
Defective VRO1 (VRO2) on F-1499
2. AUX inoperative |
Symptom Check Point
2-1. Both channels inoperative —_—_—__—____12.
2-2. One channel inoperative
1) Land R-ch will be operative when
MONDO switch is pushed in (It’s MONO position)
2) One channel will be inoperative when MONO
switch is push in 14.
1):
‘6,
7.
18.
1D:
3. MIC — —
2.
22
4. PHONO inoperative
4-1. Both channels inoperative 23:
4-2. One channel! inoperative
1) Reverse the output cords of L and R-ch from
turntable
1-1) Inoperative channel pe te
25
1-2) Inoperative channel not ae Bia
27,
5-3. Troubleshooting on Tuner Section
1. Both FM and AM inoperative (PHONO operative)
1-1. Both channels inoperative
1) 13.6V not supplied to terminal [03], [06], on F-1479-——1.
2) 13.6V not supplied to terminal [03], [06], on F-14792.
1-2. One channel inoperative
1) AM section inoperative
2) FM section ee
2. FM Section
*Before check, set MUTING switch to OFF (Pushed in)
2-1. FM inoperative only
1) Tune FM signal or FM broadcasting station
1-1) Signal meter operative
(Interstation noise too low compared
with proper unit)
CO wo Om 10.
to page 12
LS:
Du Rw
Cause & What to Do
Defective power supply section (F-1500)
Imperfect contact of SELECTOR switch
S9a (S9b)
Defective TRO1, FETO1 (TRO2, FETO2) on
F-1504
Imperfect contact of TAPE MONITOR
switch $1, 52, MONO switch $3
Defective BALANCE volume VRO1
Imperfect contact of SELECTOR switch
$9a (S9b)
Imperfect contact of SP SELECTOR switch
$10a, $10b
Defective F-1499
Defective power supply section (F-1500)
Defective TR601, TR602 on F-1504
. Imperfect contact of MIC jack
Defective power supply section (F-1500)
Imperfect contact of the output cord
. Defective turntable
Defective
TRO1,
TRO3
(TRO2,
TRO4)
on
F-1503
Imperfect
contact
of
SELECTOR
switch
$9a
(S9b)
Defective power supply section (F-1500)
Imperfect contact of SELECTOR switch S9c
Defective SELECTOR switch $9a (S9b)
Defective SELECTOR switch $9a (S9b)
Defective TR17 (TR18) on F-1479
Defective Low Pass Filter L.P.F. 11
. Defective ICO1, [C02 on F-1479
. Defective TO1~TO5 on F-1479
. Defective DO1, DO2 on F-1479
Defective IC03 on F-1479
itil a eS