Yaesu FT-901DM Maintenance Service Manual page 92

SERVICING
(2) No reception
(a)
(b)
(c)
(d)
(e)
(f)
S-meter OK, but no
audio output from
speaker
No audio output on
some mode:
LSB/FSK
USB/CW
AM
FM
Some mode
No audio output,
S-meter off scale
Speaker appears OK,
no S-meter deflection
MARKER ON, only
slight S-meter
deflection on the
marker signal
Normal S-meter
deflection against
marker signal |
(S9 +10 dB nominal) |
* Defective speaker
* Defective TA7205AP or 2SC1000GR
on PB-1705
Defective audio circuit around above
transistor/IC
Defective EXT SP jack
Defective X70;
Defective X72
* Defective Dso, (PB-1704)
* Defective Qsor (PB-1705)
Pe ee
Defective Qoo: —Qoos
Defective mode switch or cold solder
joint on switch
Defective RF GAIN control
Defective Qso7, Quos
Defective RL; , Qso7, VR2
Defective 19.7475 MHz xtal
Defective Qaos , Qaog (PB-1704)
Defective Q3o3 (PB-1716)
Defective Q>,. (PB-1703)
Defective Q:o: —Qios (PB-1702)
Defective Q3o: , Q302, Q3os (PB-1716)
Defective Qso1 —Qsos , Quos, Qaio (PB
1704)
Low VCO output (see section on
COMMON CIRCUITS)
Defective T, , T2202 , OF C2406
Check tuning or Tyo2, T3o:—Tsos3,
Tao1 —Taos
* Tracking error in RF coils
* Defective XF3o2 —XF303 or XFao1
* Defective RH-1 (lamp fuse)
* Defective RL,
* Defective S3103
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