Genius 2793 Manuel D’Utilisation
169
,
181
.
Problem
Probable Solution
Retrace
Lines .
Tests
1.
2.
3.
If any of the voltages are
not in the listed voltage
range, replace IC
not in the listed voltage
range, replace IC
927
.
Measure voltage, auto bias IC
927
pins 2, 4, & 6 for 5.5V to 6.5V.
927
Also measure voltage, pins 3, 5,
& 7 for 1.1V to 2.7V
& 7 for 1.1V to 2.7V
927
Measure voltage, LM324
920
pin 5. Should be less than 4.5V.
920
If old style C-Film (no solder
connection) & pin 5 voltage is 4.8V
add a 7.15K resistor pins 8 to 11.
Otherwise replace C-Film.
connection) & pin 5 voltage is 4.8V
add a 7.15K resistor pins 8 to 11.
Otherwise replace C-Film.
Check video gain line (J
215
)
scope sync on Vs
331
, .2mS/cm,
and verify V. & H. blanking.
If either V. or H. blanking is
missing, go to that circuit for
further tests.
missing, go to that circuit for
further tests.
215
Turn down M. Gain to minimum.
Problem
Probable Solution
No
Power.
Tests
1.
2.
3.
If the zener is shorted and the fuse
is blown, replace fuse
is blown, replace fuse
146
,
zener
181
, power FET
136
,
and the C5184 IC
115
.
146
If the power supply chirps, check
for shorted secondary voltages by;
for shorted secondary voltages by;
If fuse is blown.
Ohm out 160V crowbar zener
Ohm out 160V crowbar zener
181
.
181
136
181
115
If PS current less than .5A and 12V
line=11.5V to 12.5V, go to next test.
line=11.5V to 12.5V, go to next test.
Apply second DC voltage to 24V
line at cathode of
line at cathode of
168
.
If PS current less than .3A, line OK.
Check base of H. output
Check base of H. output
433
for
drive waveform. If OK connect 24V
line to V+ line and check flyback
waveform at collector of
line to V+ line and check flyback
waveform at collector of
433
.
(Without H. deflection load, PS
chirps) If large and small pulses
observed, replace the FBT.
chirps) If large and small pulses
observed, replace the FBT.
Apply external DC PS to 16V
line at cathode of diode
line at cathode of diode
169
.
If the power supply chirps and
high voltage can be heard.
high voltage can be heard.
Ohm out the 17V line; V- to anode
of
of
141
,
141
,
149
,
139
,
132
,
J-Film pins 8-14 & IC
115
pin 15.
Disconnect power to chassis.
FBT Check at low voltage;
With power applied, check voltage
ground to (V-) anode of diode
ground to (V-) anode of diode
156
.
If 0V to 100V, ohm out fuse
146
&
inrush current limiter
159
25
Ω
to .5
Ω
.
Measure voltage, V+ line is 0V &
PS chirps
PS chirps
Ohm out crowbar zener diode
181
.
Also ohm out H. output Xsr
433
.
First, ohm out diodes;
142
,
168
,
169
168
142
168
169
181
433
433
115
141
139
132
4.
5.
Problem
Probable Solution
Monitor
Shuts
Down.
Tests
1.
2.
If solution, check fault circuit.
Disable fault; clip
019
to GND.
019
Check voltage across cap.
846
5-10V
If screen turns bright & shutdown.
3.
If shutdown right after power up.
Check V+, Hfo, & EHT at power up.
Measure EHT,
should be less than 27KV.
Disable shutdown; clip V- to
109
.
109
4.
156
159
433
181
846
215
146
149
141
97