Sony CRF-150 Service Manual page 3

SONY.
SERVICE MANUAL
SUPPLEMENT SErrewoen, 1970
Subject: 1. Troubleshooting guide
USA model 31,800
02718
ааа
and lat
GENERAL EXPORT
"
} | model 42,420 J
1. TROUBLESHOOTING GUIDE
Trouble | Band Symptom Сане Remedy
No sound | mw 1)08V or higher | 1) Leaky tuning 1) Apply 20У de between
(Af circuit at the emitter of | capacitor the rotor and the stator
normal but 0304. (06 to of the tuning capacitor to
no sound
07 V in normal)
Produce а spark
from
speaker.)
2) № sound even | 2) Defective bar antenna | 2) Replace the сой.
и "the bar | сой
antenna сой is
adjusted
3) Collector voltage | 3) Internal resistance of | 3) Replace the tuning meter
at Q306 is too | — the tuning meteris too
low. (2.75V is | high
normal)
Sw2-10 | No sound at the | Shorted padding capac | Replace these capacitors
high-frequency end | itor. (C247, C250,
of each band C256, C259, C262
Normalsoundatthe | C268, C271)
low-frequency end
Low FM
Noise heard during | Antenna lead (coaxial | Resolder the lead
sensitivity reception cable) of tuner touches
the tuner case.
sui Great difference in | Yellow lead of the switch | Resolder the ead.
noise level be: | is connected to ground.
tween SHARP and
BROAD positions
of the SELECTIV
TTY switch
sw2-10 | Noise heard all over | 3.8 to 4.1V at the emit- | Adjust R369 for 45V.
the SW bands. ter of Q309. (45У is
normal)
Shock FM 1) Shock noise 1) Shield plate touching | 1) Separate the shield plate
noise the CP printed circuit | from the printed circuit
,
board
board
2) Shock noise. 2) Leads of capacitors | 2) Cover the legs of these
mounted on the сот | capacitors with plastic
ductor side are touch | tubing.
ing the legs of IFT
uw 1) Shock noise. 1) Loose contact in the | 1) Replace the switch
pilot lamp switch.
2) Shock noise 2) Loose nut on the EXT | 2) Tighten mut, then secure
ANT terminal with contact cement
= 4 =