Fukuda Denshi FCP-7101, Service Manual

Page: 25 / 170

Maintenance
2 - 5
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Troubleshooting related to supply voltages
* The following troubleshooting assumes that the fuses F6 and F3 are not
blown. Check fuses first when you have a trouble with the supply voltage.
Item to Check Method of Checking and Corrective Action Place to Check
+3.3V
Check that
+
3.3V is applied to terminal C312 on the
MAIN BOARD. Check also that LED5 is kept ON.
If voltage is not applied,
+
24V may not be supplied
or IC46 may be faulty.
C312
LED5
IC46
REFERENCE
P5-37,39
+3.3STB Connect the DC plug without starting the equipment,
and check that +3.3V is applied to terminal C314 on
the MAIN BOARD. If not, +18V may not be
supplied or IC62 may be faulty. IC62
REFERENCE
P5-42
+1.8V
Check whether or not
+
1.8V is applied at terminal
C317 on the MAIN BOARD.
If not applied, check whether or not
+
5V is applied at
IC45 pin 8.
If not applied, refer to the remedy for absence
of
+
5V. If voltage is applied, IC45 may be faulty.
C317
IC45 pin 8
REFERENCE
P5-39
+5V
Check that
+
5V is applied to terminal C311 of the
MAIN BOARD. Check also that LED4 is lit.
If voltage is not applied,
+
24V may not be supplied,
or IC47 may be faulty.
C311
LED4
IC47
REFERENCE
P5-39
+5V STB
Check that
+
5V is applied to IC43 pin 1 of the
MAIN BOARD. If not, IC43 may be faulty.
IC43 pin 1
REFERENCE
P5-38
+24V
Check that
+
24V is applied to C101 terminal of the
MAIN BOARD.
If not, IC42 or Q25 may be faulty.
C101
IC42,Q25
REFERENCE
P5-37
-24V(V
EE
)
Check that
−
24V is applied to P1 pin 12.
Check also that
+
3.3V is applied to IC1 pin 6.
If not, see troubleshooting for absence of
+
3.3V.
If
+
3.3V is applied, IC1 or IC7 (CPU) may be faulty.
P1 pin 12
IC1 pin 6
IC7 pin 13
REFERENCE
P5-32,27,28
VTRF
Check that
+
6.2V is applied to C274 terminal. If not,
T1 (FT2155) may be faulty.
Check that 125kHz rectangular waves are input to
IC20 pins 13 and 15. If not, IC8 (FPGA) may be
faulty.
C274
T1
IC20
IC8
REFERENCE
P5-36,29
+5VDF(+2.5VF)
Check that
+
5V is applied to C275 terminal. If not,
VTRF may not be generated, or IC40 may be faulty.
C275
IC40
REFERENCE
P5-36
+3.3VDF
Check that
+
3.3V is applied to C276 terminal. If not,
IC39 may be faulty, or VTRF (about
+
6.2V) may not
be applied to IC39 pin 6.
C276
IC39
REFERENCE
P5-36