Page 1
A. Power Supply Failure
Repair Flow Chart
105E CM23 GSIII
9 Go to cover page
61
1. Sympton :
no startup sound
LED light off
2. Sympton :
hicup mode with
startup sound or
blinking LED
7112/7115/7116/7117
check
check 7102 pin1
100V<pin1<380V
NO
check
1101/6101/
7101/2106
Turn power off
check the resistance for
all output voltages+180,
80,12,-12,-6,+5,+8 V
check 6131~6136 short?
check 7111
open circuit
Ok
check 7102
pin14 > 2V
NO
check
3121/6112/1106
3123/3119/3125
replace 7102
check 7102
pin 6 < 13.5V
OVP possibly active
No
check 6111
Ok
No
Ok
check 7102
pin 8=2.4V
NO
replace 7102
check
3115/6107
/6111
OK
OPP possibly active
check 3103,3111~3114
3108,3109,6102,2121
check 7102
Ok
pin4 output ?
check 7102
pin 5 < 0.5V
No
Ok
check
6165/3107/
3105/7101
check
pin6>8V
NO
OK
3. Sympton:
abnormal sound
check 7153 pin3
voltage dip
check
+5V loading current
check
frequency
F=77KHZ
No
adjust
3129
Ok
replace 5113
check 7153 pin1
11V< pin1 < 15V
No
check
6144/3146/3147
3148/7117/2142
check 7101
drain waveform
right?
Ok
replace 5113
7102 pin14 OOB
possibly active
NoOk
short 7116 pinC
check CPU pin 22
and 7805 emitter
No
replace 5113
Ok
check
6103/3104
2107/2111
3Back
Forward4
Page 2
62
105E CM23 GSIII
9 Go to cover page
B.Video
Repair Flow
1.Sympton :
(with wite pattern)
no picture
green LED on
rough check for R,G, B
1. video input= 0.7V
2. 7099video output =2.5V
3. 7099 video output > 35Vpp
check heater
= - 6.3V
EHT=25KV
check Xray prot.
check blanking
7099 pin16
Repair Flow Chart
check blanking
7099 pin16
Ok
check
No
7099 pin2
Ok
check
VG1 < -150V
check
VG2 > 450V
check
R,G,B output
No
30<2725<80
30<2733<80
30<2753<80
Ok
check DC restoration
7013,,7033,7053
7014,7034,7054
2.Sympton :
no video (or dim),
only raster with/without retrace line
green LED on
check 7099 pin24
2V< ABL < 5V
check 7099
pin11 HFLB
check
7501 pin16
check 7099
pin5 CLBL
Ok
OkNo
Ok
check Vg1
Vg1=0V
check 7099
pin 6,8,10
input swing
No
replace IF
cable
replace 7301
No turn down Vg2
check 7099
pin 6, 7,9
input swing
Ok
replace 7099
check cathod
+78V,3779
check 7099
pin 1,2,3
output swing
3. Sympton :
no OSD or
OSD out of sync.
7099 pin12
3Back
check
Ok
check 7099
pin 2,3,4 input
Ok
check
7099 pin1
No
replace 7099
No
check
7099 pin10
VFLB
check 7099
pin2 VCO
pin3 RP
check 7099
pin5 HFLB
No
replace 7099
Ok
check 7099
pin 7,8(IIC)
Forward4
Page 3
C. Horizontal deflection
output repair flow :
Repair Flow Chart
105E CM23 GSIII
9 Go to cover page
63
1. Sympton :
without
H-deflection.
2. Sympton :
East /West
corr.
replace 5612
check Hsync
7606 base
check 2625
parabola
exist
check
180V
check Hsync
7605 base
Ok
6602,7601,7602
check
7611 ~ 7613
parabola exist
check Hsync
check Hsync
7603 drain
No
check
check 7501
parabola exist
7501 pin8
Ok
pin11
check Hsync
7501 pin6
No
refer 7501 check list
or replace 7501
refer 7501
check list
3. Sympton :
H-linearity
(full freq. range)
4. Sympton :
Rotation
5. Sympton :
H_dc shift
enter factory mode
check linearity data
in eeprom
check
7682,7683
check
7607,7608
check 7621
pin 1,2,3,4,8
check
7617,7618
3605
check
3655~3656
7614~7616
check cpu
7801
pin 4,5,6,42
control range
check
3681/3698
check cpu
7801 pin28
check
3643 / 3649
replace 5611
check cpu
7801 pin29
control range
3Back
6. Sympton :
Focus
enter OSD
function
disable morier
check
7685collector
check
7501 pin 32
check
5671
Forward4
Page 4
64
105E CM23 GSIII
9 Go to cover page
Repair Flow Chart
D. Vertical Deflection Failure
Sympton :
one horizontal line
V_size is abnormal
too large/small (small)
basic check
+12/-12V/+80V
check
3401,3402
3407,3408
good
No
check
7401
Ok
check
3412,3413
check
6405,6402
good?
No
check
7401
Ok
Ok
check 7501
pin2,pin3 ramp
exist ?
3Back
No
check
7501
Forward4
Page 5
Repair Flow Chart
105E CM23 GSIII
9 Go to cover page
65
E. CPU
check list
Basic Check
3. H-EHT
4,5,6 (Q3,Q2,Q1)
S-cap switch
13~17 Hsync / Vsync
check cpu pin11/ pin32= 5V
pin9/pin10=12MhZ
pin12/pin31=gnd
H size compensation for
the load variance
check Q1-Q3
pin11/pin12/pin13
low:0
hi :1
check sync.
Hsync_in=pin27
Vsync_in=pin28
Hsync_out=pin21
Vsync_out=pin20
Fh-khz Q1 Q2 Q3
<27.00 0 0 0
27.50~33.24 0 0 0
33.24~36.51 0 1 0
36.51~42.38 1 0 0
42.38~47.48 1 0 1
47.48~53.10 1 1 0
53.10~58.25 1 1 1
1 . Normal
Fhout=Fhin
Fvout=Fvin
2. Self test
Hout=46.875Khz
Fvout=75Hz
3.sync out of rang
Fhin>72.8
Fvin>168Hz
18. Hunlock
19. Blanking
21, 22 P.S.
LED
23. Degauss
26, Reset
check pin10
normal=Hi
blank=low
check pin3
normal : low
change timing : Hi
pin 14 STBY
pin 17 OFF
check pin24
active=hi
no active=low
check pin 3
from 5V to 0V
power saving pin14 pin17
normal hi hi
standby low hi
off low low
check
2814 / 6811 / 3834
3Back
Forward4
Page 6
66
105E CM23 GSIII
9 Go to cover page
Repair Flow Chart
30. ABL-CON
33. Keypad
34. Selftest
36,37. DDC bus
check pin2
output from 0V to 5V
check key
Enter,Up,Down,Left,Right keys
check pin26
1.no H/V sync & IF cable pin5 floating - show msg.
2.H/V sync exist & IF cable pin5 to ground - normal
3.H/V sync non-exist & IF cable pin5 to gnd -power saving
4.connect a 15k resistor with IFcable pin5 -factory mode
5.connect a 5k1 resistor with IF cable pin5 - burn in mode
check idle status
sda=pin36=hi
scl=pin37=hi
check
7804 24LC21
check 3836, 2821
3891~3895
38,39. IIC bus
40, VCLK
EEPROM
42. Shift_LED
check idle status
sda=pin38=hi
scl=pin39=hi
check 7803 pin 15,16
Low : write enable
Hi : write disable
check pin25
output from 0V to 5V
check
7803 24LC16
7501 TDA4841
7304 MTV018-27
7301 TDA4886
3Back
Forward4
Page 7
Repair Flow Chart
105E CM23 GSIII
9 Go to cover page
67
F. TDA4857
Check List
1. HFLB
(from H.defl)
2. Xray
(from LOT)
3.4.5.6 B+ control
Basic check
Vcc>9V
during startup
if no exist
if active
a pin3 amplify pin5 and it compare to pin4
b. pin4 generate the saw_tooth wave
c. pin5 input voltage for the square output waveform
d. pin6 pwm output to 7601 & 7602 base
Vcc=pin9=pin10=12V
gnd =pin7=pin25=0v
pin16
CLBL=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 pulled to
ground by 7508
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 1, 7
the input sync from
cpu pin 14,17
3Back
16. CLBL
Vertical blank will be activated = hi
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
68
105E CM23 GSIII
9 Go to cover page
Repair Flow Chart
17. Hunlock
18. IIC sda = hi
19 IIC scl = hi
21 EHT_compen.
22,23,24
VAGC,VREF,VCAP
Hunlock pin is floating while pll1(pin26) is
unlock in searching mode
the initial sequence of IIC IC
7501,7301,7304
compensate for the V_size
owing the load variation
pin22 determin the AGC
pin23,pin24 determin frequency
50Hz< freq. <160Hz
pin26 determin the
26,27,28,29
Hpll1,Hbuf,Href, Hcap
30. PLL2
32. Focus to 7685 for the V dynamic focus
1.compare the HFLB and control the phase of HDRV
2.softstart
pll1 loop filter
pin 27,28,29 H-Freq
working range
compensate for the H_size owing the load variation31 EHT_compen.
30K<freq.<58KHz
3Back
Forward4
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