Realistic STA-235B User manual

ruLtstC.
Serulce amuafl
ADDENDUM
for STA-235B
AM /FM STEREO RECEIVER
Gatalog Number:31 -2065
This ADDENDUM covers the changes made for "B" version of the STA-235.
For complete coverage of this model, you must refer to both this ADDENDUM and the
original Service Manual for the STA-235.
cusroM MANUFACTURED FoR RADto sHncr[A DVtstoN 0F TANDv coRponAloN

CONTENTS
1 . SPECIFICATIONS 2
2. BLOCK DIAGRAM 3
3. ALIGNMENT PROCEDURE 4
4. ALIGNMENT POINTS 5
5. TROUBLESHOOTTNG ............. 6
6. TUNEB BOARD OO42 .......... .............7 - I
7, MAIN AMP BOABD OO45 9
8. TONE AMP & AUTO-M BOARD 0043 ........ ..... 10
9. ELECTRICAL PARTS LIST .......11 _ 18
10. M|SCELLANEOUS PARTS L|ST ......... ............... 19
11. SCHEMATIC DIAGRAM ......... .SEPARATE SHEET
1. SPECIFICATIONS
The specifications of STA-2358 are the same as STA-235 except for output voltage of FM
section.
FM SECTION
13. OUTPUT VOLTAGE
(at 75 kHz dev., 400 Hz mod., 1 mV input)
NOMINAL LIMIT UNIT
STA.235
STA.235B
0.9
o.7
0.913 dB
0.713 dB
V
V

2. BLOCK DIAGRAM
sl:)Els
o-tr
h
Gtr
h
t-,
IE
e r,P
3 ='E-A9=
- x662
6EH--ii q
PFgSsli
9I
: - - -?. ,
2 n D d ? iln r so
e 5 + * + + E e = +3 E EE
Irn]
3
E-r
rPF

3. ALIGNMENT PROCEDURE
AM RF AND IF ALIGNMENT
Not changed
FM RF AND IF ALIGNMENT
Adjustment points of Steps 4,5,6 and 7 should be changed.
MPX ALIGNMENT
FM ANTENNA
TE RM INAL
(300s,)
ALIGNMENT CONNECTION
Adjustment points of Steps 1,3 and 4 should be changed.
TAPE OUT
STEP ADJUSTMENT Refer to Fig. 4
STA-235 STA.235B
4
5
6
7
L203 (Pink core)
L203 (Blue core)
vR202
VR2O1
T201 (Bottom)
T201 (Top)
VR201
vR202
101. l-102
103, L104
T101, TC101
TC102, TC103
TC104
FM SIGNAL
GENERATOR FM DUMMY
ANTENNA
300a
STEREO
MODULATOR
STEP ADJUSTMENT Refer to Fig. 4
STA-235 STA.235B
1
3
4
VR3O2
VR301
VR3Ol
VR301
VR3O2
VR3O2
4

4. ALIGNMENT POINTS
t
r. t €
o
@
E
: i: a,
',.,. i ti tai
eI
t
E
o
@
ts
N
e
sl
o
sl
o
F'
E
6l
o
oe
e
o
(\l
E
N
c,
N
E
6
<l
cl
<l
ts
\ r :i$
N m hN F N @ m sf $
o o c, o o oct o o o o o o o o
tf st sl
J L ts (J (J (-)(.) c.! J J C' J (J F J
Fig.4

5. TROUBLESHOOTING
Refer to page 14 and 15 of STA-235 Service Manual.
The following items should be changed.
Symptom Cause and Remedy
13) FM does not operate. E) Delete
G) Delete
H) Defective lC 1C201
Replace the lC.
l) Defective IFT T101 orT2O1
Replace the defective components.
J) Defective resistor R2O1, R2O2, R203, R2O4, R205,
R206, R208, R209, R213, R219 or R22O
Replace the defective resistor(s).
K) Defective capacitor C203, C112 or C2O1
Replace the defective capacitor(s).
L) Defective transistor TR101 ,TR102, TR103 0r
coil L101 , L1O2, L103, L104 of Tuner Board
oo42
Replace the defective component(s).
14l, Poor multiplex separation. B) Transistor TR301, TR302 or 1C301 of Tuner
Board 0042 defective
Replace the defective component(s).
15) Stereo indicator does not
light. C) Defective lC lC30'l or resistor R321
Replace the defective component(s).
16) FM volume not sufficient. A) lf volume of both L and R channels not
enough: Front-End defective or faulty lC
1C201, 1C301 or capacitor C227, C301 of
Tuner Board 0042
Locate and replace the defective component(s).
B) lf sound of one channel not enough: Defective
LPF301 or TR301 in case of L channel, or
defective LPF302 or TR302 in case of R channel
Replace the defective component(s).

TUNER BOARD OO42 (TOP VIEW)

TUNER BOARD OO42 (BOTTOM VIEW)

MAIN AMP BOARD OO
li:*iii*s,,i:tiil
MAIN AMP BOARD OO4I
lr:a:i.1ltr,iGri:.::,:!r,i1':r:i1r:31u1ii:t,,::,r!1',:1.,ir,
,t,l:rl.r.iitrar1;i:1.r:iilrl:i:ilqa.t:tiltitt::jrlti:e:i
!rl!r::!i:lli;alilil;ri,ilrq:.1{::i11lli]i:lljl;
ilit'
tLt6'
'rir lr.;, r{. i;i t

BOARD 0045 (TOP VrEW)
,,$j*i, f$gll:$i
OARD OO45 (BOTTOM VIEW)