Page 1
A. Power Supply Failure
Repair flow chart
105B2 CM23 GSIII
9
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43
Sympton:
no startup sound
LED light off
check 7112
pin 1,2,4,5
check 2105
100V< C2105<380V
N
check
1101/1102/
6101/7102
check OVP
7106 / 7107
latch?
Y
7103 /7104
check 7103
pin8 = 5V
3135/6106/7103
check
short
N
check
YYY
check 7103
Y
pin 4 osc.
freq=40Khz
2110/2111/
3108/3131
check 7103
pin1 = 0V
N
check
N
Y
check 7103
pin6 output ?
Y
check
6115/3113/
3125/7102
Sympton:
startup failure
LED blinking
Burst sound
check
6172/6157/6158/
6160/6161/6112
short
during startup
N N
check
H-deflection
check
+180,80,5,12,
-12, 8, 6
short
replace 5110
check 7103
OPP possibly active
check 3116 /3117 /
3118 / 3122
check 7501
Hunlock pin17
pin3>1V
Y
N
check 7801
Stby pin14
3Back
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Page 2
44
105B2 CM23 GSIII
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B.Video
Repair Flow
1.Sympton :
( input a white pattern signal )
no picture
green LED on
Repair Flow Chart
check R,G, B input / output
1. video input= 0.7V
2. 7301video output =2.5V
3. 7701 video output= 35V swing
check
heater = 6V
check
EHT=25KV
Ok
check
VG1< -100V
check CRT
2.Sympton :
no video ( or dim )
only raster with green LED
Ok
check blanking
VG2 > 400V
7501 pin16
Ok
check VG1
VG1 <-100V
check
N
check Xay-prot.
7501 pin2
Y
N
turn high
VG2
Y
check
7501 pin17
check R,G,B output
30<2725<80
30<2733<80
30<2753<80
N
check DC restoration
7722,7732,7752
7721,7731,7751
check +80V
supply
N
3Back
check 7301
pin24
2V< ABL < 5V
check 7301
pin11 HFLB
check 7301
pin5 CLBL
No
check 7501
pin16
Ok
Ok
check 7301
pin 6,8,10
input swing
No
check
IF cable
replace 7301
check 7701
pin 8,9,11
input swing
Ok
replace 7701
N
check 7701
pin 1,3,5
output swing
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Page 3
C. Horizontal deflection
output repair flow :
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45
1. Sympton :
without
H-deflection.
2. Sympton :
East /West
corr. fail
replace 5611
check Hsync
7606 base
check short circuit
check 2629
parabola exist
check Hsync
7605 gate
check
7623 drain
180V
N
5611 pin4
N N N
Ok
check
7610/7611/7612
parabola exist
check Hsync
7621/ 7622
emitter/collector
6631,7621,7622
check Hsync
7501 pin8
N
check
check 7503
pin11
parabola exist
OkOk
check Hsync
7501 pin6
N
refer 7501
check list
refer 7503
check list
3. Sympton :
H-linearity
(full freq.range)
4. Sympton :
H_dc shift
Enter factory mode
check linearity data
in the eeprom
check
1602 / 3644
check
5608 / 7614
refer 7801check list
check
6634 / 6635
check
7617/7619
check
1602
refer 7801check list
Q1/Q2/Q3
3Back
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Page 4
46
105B2 CM23 GSIII
9
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D. Vertical Deflection Failure
Repair Flow Chart
basic check
+12 /-12V /
+60V ( C2516 )
Sympton :
one horizontal line
V_size is too large / too small
check
3410,3403
3407,3405
check
6403
check 7401
pin2,pin3 ramp
No
check
7501
N
Ok
replace
3410,3403,3407,
3405,7401
check
3411,3412
3Back
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Page 5
Repair flow chart
105B2 CM23 GSIII
9
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47
E. CPU
check list
Basic Check
2. Tilt
3. Abl-con
5. Reset
check cpu
B+ pin6=5V
OSC.=12MHz
check pin 2
pwm output from 0V to 5V
check pin 3
pwm output from 0V to 5V
check pin5
from low to hi
check
3816 / 2820
13. H-unlock
18,19,20
S-cap switch
21 , 28
stby , off
22. Key
check pin13
normal : low
H-unlock : hi
check
Q1,Q2,Q3
check
pin 21 / 28
7804 / 7805
check pin22
check up , down , left , right, enter
normal hi hi
standby low hi
off low low
check
3850 / 7809
pin21(stby) pin28 (off)
3Back
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Page 6
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24. Selftest
Repair Flow Chart
check pin24
1.no H/V sync & IF cable pin5 floating - free run mode
2.H/V sync exist & IF cable pin5 to ground - normal
3.H/V sync non-exist & IF cable pin5 to gnd - power saving
25,26. DDC
sda,scl
30,31 IIC
sda, scl
40,41,34,33
Hs_in,Vs_in,Hs_out,Vs_out
idle status
idle status
sda= pin25 = hi
sc l= pin26 = hi
sda=pin30 = hi
scl =pin31 = hi
check sync.
Hs_in=pin 40
Vs_in=pin 41
Hs_out=pin 34
Vs_out=pin 33
check
7801
check
7806 24C08
7501 TDA4857
7301 TDA4886
7302 TDA 4822
7304 MTV018N
1 . Normal
Fhout=Fhin
Fvout=Fvin
2. Self test
Fhout=46.875Khz
Fvout=75Hz
3. sync out of rang
Fhin> 70KHz
Fvin>168Hz
3Back
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Page 7
Repair flow chart
105B2 CM23 GSIII
9
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49
F. TDA4857
Check List
1. HFLB
2. Xray
( from LOT )
3.4.5.6 B+ control
( from H.defl )
Basic check
Vcc>9V
during startup
if active
a pin3 compare the level with pin 4
b. pin4 generate the saw_tooth wave
c. pin5 controlled output duty
d. pin6 pwm output to control B+
if no exist
Vcc =pin9=pin10=12V
gnd =pin7=pin25=0V
pin16 / 17
CLBL=hi
HUNLOCK = hi
pin17 = Hunlock = floating
pin30 = Hpll2 = 0V
pin6 = HDRV = floating
pin8 = BDRV = flaoating
pin12 = Vout1 = floating
pin13 = Vout2 = floating
pin16 = CLBL= Hi
inhibit pin6 output
if pin3 is low
8. HDRV
11.EWDRV
12,13 Vout1/Vout2
14,15 Vsync,Hsync
to H_deflection.
7605 base
to H-deflection east/west control
7612 base
differential input
to 7401 pin 2, 3
V&Hsyncinput from
7801 pin 33 , 34
3Back
16. CLBL
pin16 is pulled up to high level at conditions
1.pin30 = softstart pll2 = 0V
2.pin26 = pll1 is unlock in searching mode
3.pin1 = HFLB no exist
4.pin2 = Xray once actived
5.pin10 = Vcc < 9V
Forward4
Page 8
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105B2 CM23 GSIII
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Repair Flow Chart
17. Hunlock
18. IIC sda = hi
19 IIC scl = hi
20 asymmetry EW output
21 EHT_compen.
22,23,24
VAGC,VREF,VCAP
pin 17 is pulled to high while PLL1( pin26 )
is not locked in searching mode
initial failure could be the following ICs
7301,7302,7304,7801,7501
to 7501 pin30
using for soft-start
compensate V_size
because of load variation
pin22 determin the AGC
50Hz< freq. <160Hz
pin23 & 24 determin the frequency
26,27,28,29
Hpll1,Hbuf,Href, Hcap
30. PLL2
31 EHT_compen.
pin26 determin the pll1 loop filter
30K<freq.<70KHz
pin 27,28,29 H-freq working range
1.compare the HFLB and control the phase of HDRV
2.softstart
compensate H_size
because of load variation
3Back
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