B5.18
T865 Fault Finding
M860-00-Preliminary
30/06/98
Copyright TEL
5.7.6
Receiver
Refer to the receiver IF and front end circuit diagrams (sheets 3 & 4) in Section 6.
High audio
distortion.
B
Note: T.B. = Test Break
(refer circuit diagrams)
Quad coil L360
tuned for min.
distortion (flat
audio response)?
Adjust L360.
Retune all
IF coils.
Check VCO
frequency OK?
Readjust TCXO
frequency.
Check IF
alignment OK?
Adjust IF coils.
Check distortion
IC350 pin 7 OK?
Fault find audio.
Check distortion
IC350 pin 7,
injecting 21.4MHz
@ -47dBm into T.B.
at &XF330 input. OK?
Fault in IC350,
&XF340, IC340,
&XF330 or
surrounding circuitry.
Check/replace.
Inject 21.4MHz
after mixer IF
output T.B.
Measure distortion.
OK?
Inject on-channel
RF into mixer T.B.
Measure distortion.
OK?
OK
Check
sensitivity
into each
IF stage.
Repair stage.
Replace TCXO.
Refer to
synthesiser
fault finding
charts.
Check TCXO
stability OK?
(see 5.5.3)
N
Y
N
Y
N
Y
N
Y
N
Y
N
Y
N
Y
Y
Y
Ensure VCO, RF
front end & IF
correctly aligned.
High audio
distortion?
Check/repair faulty
stage or component.
Check DC
conditions OK?
(see cct diagrams)
Check sensitivity
into each stage
(see 5.5.2)
See Chart B
(below).
Replace
faulty device.
Y
N
N
Y
Ensure links SL405
to SL440 & link B
are set correctly.
(see Section 3.7)
Poor sensitivity:
worse than -117dBm.
A
Summary of Contents for T860 Series II
Page 6: ...AII M860 00 Preliminary 30 06 98 Copyright TEL...
Page 12: ...A2 4 Mechanical M860 00 Preliminary 30 06 98 Copyright TEL...
Page 18: ...BII M860 00 Preliminary 30 06 98 Copyright TEL...
Page 20: ...B1 2 T865 General Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 30: ...B1 12 T865 General Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 32: ...B2 2 T865 Circuit Operation M860 00 Preliminary 30 06 98 Copyright TEL...
Page 42: ...B2 12 T865 Circuit Operation M860 00 Preliminary 30 06 98 Copyright TEL...
Page 56: ...B3 14 T865 Initial Tuning Adjustment M860 00 Preliminary 30 06 98 Copyright TEL...
Page 58: ...B4 2 T865 Functional Testing M860 00 Preliminary 30 06 98 Copyright TEL...
Page 84: ...B5 20 T865 Fault Finding M860 00 Preliminary 30 06 98 Copyright TEL...
Page 86: ...B6 2 T865 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 90: ...B6 6 T865 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 110: ...T865 Preliminary PCB Information T865 Grid Reference Index Page B6 26...
Page 112: ...CII M860 00 Preliminary 30 06 98 Copyright TEL...
Page 114: ...C1 2 T867 General Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 148: ...C4 2 T867 Functional Testing M860 00 Preliminary 30 06 98 Copyright TEL...
Page 154: ...C4 8 T867 Functional Testing M860 00 Preliminary 30 06 98 Copyright TEL...
Page 170: ...C5 16 T867 Fault Finding M860 00 Preliminary 30 06 98 Copyright TEL...
Page 172: ...C6 2 T867 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 176: ...C6 6 T867 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 204: ...T867 Preliminary PCB Information T867 Grid Reference Index Page C6 34...
Page 206: ...DII M860 00 Preliminary 30 06 98 Copyright TEL...
Page 208: ...D1 2 T869 General Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 214: ...D1 8 T869 General Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 216: ...D2 2 T869 Circuit Operation M860 00 Preliminary 30 06 98 Copyright TEL...
Page 224: ...D3 2 T869 Initial Adjustment M860 00 Preliminary 30 06 98 Copyright TEL...
Page 230: ...D4 2 T869 Fault Finding M860 00 Preliminary 30 06 98 Copyright TEL...
Page 238: ...D4 10 T869 Fault Finding M860 00 Preliminary 30 06 98 Copyright TEL...
Page 240: ...D5 1 2 T869 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 244: ...D5 2 2 T869 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 254: ...D5 2 12 T869 PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...
Page 256: ...EII M860 00 Preliminary 30 06 98 Copyright TEL...
Page 258: ...E1 2 T860 VCO PCB Information M860 00 Preliminary 30 06 98 Copyright TEL...