1. CTV Trouble Shooting Guide
Chassis : Venus-1BST
Volume 1
By QA Videocon Industries

2. Content Chassis : Venus-1BST Preface
Important tips...……………………………………………………………………..Page 01
Circuit Diagram………………………………………………………………………….02
Design Data………………………………………………………………………………03~07
Applicable models………………………………………………………………………..08
Set Dead…………………………………………….……….………………..……09
Set Std. by…………………………………………………………………………..10
No Sound…..……………………………………….………
No Raster………………………………………….………
H- Line…………………………………………….……………………..….……...13
V- Line………………………………………………………………………………14
No Color ……………………………………………………………………………15
Snowy Picture / No Tuning /Channel Skipping….………………………………...16
Plain Raster ………………………………………………………………………...17
Retrace line…………………………………………………………………………18
One Color Missing (Red/ Blue/ Green)…………………………………………….19
AV Mode No Color & No Picture …………………………………………………20
RF Mode No Color & Intermittent No Color………………………………………21
Defocus Picture (Ghost Effect) ……………………………………………………22
Color Patch…………………………………………………………………………23
Remote Not Operate……..…………………………………………………………24

3. Chassis : Venus-1BST
Preface
In this Guide Book, circuit diagram, their associated voltages, Design & Service data, and step by step trouble shooting guidelines are given for Service Engineer reference.
Trouble shooting procedure and circuit diagram used in this manual are based on mainly PAL color transmission system.
When actually trouble shooting, technician should always refer schematic diagram of defective receiver, and symptom wise step by step repairing tips should be followed to avoid repeat calls and to give one time solution to our customers.

4. Important Tips Chassis : Venus-1BST
A good repairman conducts a prompt diagnosis of the trouble symptoms and repairs the defective set in the shortest possible time. Do not trouble-shoot a circuit unless you have determined what stage in it is defective. When trouble-shooting a particular stage, always remember its function. This will help you diagnose its operation and find the defective stage and the defective component.
Wear cotton gloves while trouble-shooting, to avoid electrical shock. Also note that, especially in tropical areas, sweat on the hands may later on cause corrosion
Never remove a component from the circuit unless you have confirmed it to be
defective. In some cases, when you suspect a component to be defective, you may find it necessary to disconnect one of its terminals, or the component itself, from the circuit for testing. Before doing this, first measure voltage or observe wave-forms. If a reading is wrong, analyze the circuit and check which component may be causing the trouble and should be tested.
4. Discharge large capacitors and the stored charge in the cathode-ray tube (CRT) to
avoid dangerous shocks—especially when trouble-shooting the CRT circuits or the
horizontal output circuit.
5. Always use standard parts recommended by company to avoid repeat failure
Page 01 of 24

5. Chassis : Venus-1BST
Double click
here for
.pdf file
Page 02 of 24

6. Chassis : Venus-1BST
Design Data
Page 03 of 24

7. Chassis : Venus-1BST
Design Data
Page 04 of 24

8. Chassis : Venus-1BST
Design Data
Page 05 of 24

9. Chassis : Venus-1BST
Design Data
Page 06 of 24

10. Chassis : Venus-1BST
Design Data
Page 07 of 24

11. Chassis : Venus-1BST
Applicable models
Sansui
Videocon
Page 08 of 24

12. Set Dead Chassis : Venus-1BST VOLTAGE CHART STR COQ765RT
Pin 1 : 250V
Pin 2 : 0 V (GND)
Pin 3 : 18.2V
Pin 4 : 1.1V
Pin 5 : 5 V
SMPS Secondary
D 815 : +17V
D 814 : +15V
D816 : +12V
D 811 : +110V
D 813 : +24V
Check AC Socket, Power cord, Power switch, Fuse
Abnormal
Replace and check
Normal
Check Rectifier diodes, NTC(NT801)
Abnormal
Replace diodes /NTC and check
Normal
Check C805, STR Pin 1 Voltages (250V),
Abnormal
Check C805, SMPS
Normal
Check 18V at Pin3 of STR
Abnormal
Check D802, VD802, R801, R802
Normal
Abnormal
Replace STR, Check secondary Voltage
Check secondary rectifier diodes
Normal
Check as per STD. BY Guideline
Page 09 of 24

13. Chassis : Venus-1BST Std. by VOLTAGE CHART STR COQ765RT SMPS Secondary
Pin 1 : 250V
Pin 2 : 0 V (GND)
Pin 3 : 18.2V
Pin 4 : 1.1V
Pin 5 : 5 V
SMPS Secondary
D 815 : +17V
D 814 : +15V
D816 : +12V
D 811 : +110V
D 813 : +24V
Micon Audio Voltages :
Pin 3: 8V
Pin56 : 0.4V
Check +B Voltage 110V at D811
cathode
Abnormal
Check D811, SMPS, FBT and replace
Normal
Abnormal
H-out Tr. Base 0.5V
Check HDT, Driver Tr. V401
Normal
Abnormal
Check SMPS secondary Voltages, VD853(8.2V) & VD852(5.1V)
Replace VD853 & VD852
Abnormal
Check by disconnecting load
Abnormal
Replace SMPS
Normal
Abnormal
Check the section loading supply
Check & Replace part
Normal
Abnormal
Dry pin no.3 & check on track for 8V, check & change crystal X201 If ok then replace micon
Check Micon Pin no. 3 for 8V
Normal
Check Micon Pin no. 56 (0.4V), Pin no. 38 (3.3V)
Abnormal
Replace Micon, V841
Page 10 of 24

14. No sound Chassis : Venus-1BST VOLTAGE CHART IC 7297
Pin 1 : 8.8V (O/P-1)
Pin 2 : 8.8 V (O/P-2)
Pin 3 : 17 V (Vcc)
Pin 4 : 0.9V
Pin 5 : 0.9V
Pin 6 : NC
Pin 7 : NC
Pin 8 : 0.6V
Pin 9 : 0V (GND)
Pin 10 : 0V
Pin 11 : 4.9V
Pin 12 : 0.9V
Pin 13 : NC
Pin 14 : NC
Pin 15 : 0.9V
Pin 16 : 0.9V
Pin 17 : 17V
Pin 18 : 8.6V
Pin 19 : 8.6 V
Micon Audio Voltages :
Pin 58,59: 3.57V
Pin 31 (UnMute) : 0V Mute : 0.6V)
Normal
Check AC Voltage across speaker
Replace speaker
Abnormal
Normal
Check Voltage at Pin1,2 & 14,15
of IC7297
Replace Speaker connector
Abnormal
Normal
Check 17V at Pin3,13 of IC7297
Replace IC7297
Abnormal
Check C878, D815, VD1, C601
Abnormal
Replace R886/ C878/D815/VD1/C601
Normal
Replace SMPS & check 17V
Normal
Abnormal
Check Voltage at pin 58,59 of Micon (3.57V)
Replace Micon
Normal
Check Voltage at pin 31 of Micon (0V)
Replace Micon
Page 11 of 24

15. No Raster Chassis : Venus-1BST VOLTAGE CHART Page 12 of 24
Screen Voltage : 675V
Heater Voltage : 6.3 V
Not Glowing
Check EHT Voltage generation
By tester on FBT anode wire
Go as per STD. BY Guideline
Tester Glowing
Abnormal
Check Screen Voltage on CRT Base (675V)
Adjust screen/Replace FBT
Normal
Abnormal
Check Heater Voltage at W77A in CRT Base (6.3V)
Replace W77A, Conn. XP501
Normal
CPT Replace
Page 12 of 24

16. H. Line Chassis : Venus-1BST VOLTAGE CHART VERTICAL IC LA78040B
Pin 1 : NC
Pin 2 : 0.57V
Pin 3 : 15.81V
Pin 4 : V
Pin 5 : V
Pin 6 : V
Pin 7 : V
Abnormal
Check Vertical Yoke Wire
Change wire, Solder properly
Normal
Abnormal
Check Voltage at pin 2 (+16.5V), pin 4 (15.3V) of Vertical IC301
Check R403, R427, D404, D402, VD401, VD402
Normal
Check Vertical IC301 Voltages
Abnormal
Abnormal
Check Micon IC201 pin 14, 15 Voltage (0.6V)
Replace Micon IC201
Normal
Replace IC301(LA78040/41)
Page 13 of 24

17. V. Line Chassis : Venus-1BST VOLTAGE CHART FBT Page 14 of 24
Pin : 274.5V AC
: 20.37V DC
Pin 2(+B) : 0V (GND) AC
: 108.5V DC
Pin 3(V+) : 41.19V AC
: 0V DC
Pin 4(v-) : 30.46V AC
: 0.13V DC
Pin 5(GND) :
Pin 6(Heater) : 7.10V AC
Pin : 41.85V AC
: 80mV DC
Pin 8(ABL) : 2.16V AC
: 6.27V DC
Pin :
Pin 10 (180V) : 23.1V AC
Abnormal
Check Yoke Conn.
Change wire & check for dry solder
Normal
Abnormal
Check Horizontal yoke continuity
Change yoke assembly
Normal
Abnormal
Check for Dry in L401 (coil) ,burn & track cut.
Resolder (L401, burn & track)
Page 14 of 24

18. No color Chassis : Venus-1BST DESIGN DATA USER DATA Page 15 of 24
Sub Colour (SCL) :
JCT & Thomson – 60
Samtel – 63
USER DATA
Colour Setting – 50
Colour System - PAL
Check Signal condition (>40dB)
Abnormal
Correct signal from Cable operator
Normal
Abnormal
Check color in User mode
Change colour step to 50
Normal
Abnormal
Check color system in User mode
Change colour system to PAL
Normal
Abnormal
Check Sub color in design data
(Refer right side Table)
Change EEPROM & Load Design data
Normal
Abnormal
Check Crystal X201 for dry solder & open
Replace crystal and check
Normal
Micon Change
Page 15 of 24

19. Snowy Picture / No Tuning /Channel Skipping
Chassis : Venus-1BST
Snowy Picture / No Tuning /Channel Skipping
VOLTAGE CHART
Tuner Voltage
Pin1 : 3.0V ~1.9V(At good signal)
Pin2 : 2.39V
Pin3 : 0 V
Pin4 : 1.8V
Pin5 : 2.1V
Pin6 : NC
Pin7 : 4.99V
Pin 8- NC
Pin V
Pin 10 –NC
Pin 11-
DESIGN DATA
AGCT Value
GDC Tuner : 25
ONIDA Tuner :
LONGSIN :
Check RF cable / Signal strength
Abnormal
Replace RF cable, Contact cable operator
Normal
Abnormal
Check sharpness setting in User mode and design data
Reduce sharpness by 50%
Normal
Abnormal
Check AGCT Value in Design data(Refer side table)
Change AGCT Value
As per side table
Normal
Abnormal
Check dry solder in all Tuner pins
Resolder and check
Normal
Abnormal
Check all Tuner Pin Voltages
Check supply related ckt.
Replace tuner
Normal
Abnormal
Check V101 transistor
Replace & Check
Normal
Replace Micon
Page 16 of 24

20. Check Micon Pin no. 12 & 13 (VIF in 2V)
Chassis : Venus-1BST
Plain Raster
Tuner Voltage
Pin1 : 3.0V ~1.9V(At good signal)
Pin2 : 2.39V
Pin3 : 0 V
Pin4 : 1.8V
Pin5 : 2.1V
Pin6 : NC
Pin7 : 4.99V
Pin 8- NC
Pin V
Pin 10 –NC
Pin 11-
Check tuner voltages
Abnormal
C 131 faulty
Normal
Check Micon Pin no. 12 & 13 (VIF in 2V)
Abnormal
Replace Micon
Normal
Abnormal
Check V101
Replace Micon
Page 17 of 24

21. Retrace line Chassis : Venus-1BST VOLTAGE CHART
IC501 VIDEO IC TDA6107JF
Pin 1 : 2.35V DC
Pin 2 : 2.35V DC
Pin 3 : 2.1V DC
Pin 4 : 0V (GND)
Pin 5 : 3.8V DC
Pin 6 : 182V DC
Pin 7 : 162V DC
Pin 8 : 155V DC
Pin 9 : 159V DC
Check Screen by adjusting FBT
(screen pot) without disturbing the upper pot.
Abnormal
Adjust pot or replace FBT
Normal
Check 180V supply on CRT Board ( CN501 Conn)
Abnormal
Replace D403 or FBT
Normal
Check R G B voltage at CN501
R , G , B 1.8V to 2V
(Pin no. 44, 45 & 46)
Abnormal
Replace Micon
Normal
Check IC501 & VD501~ VD504 R G B voltages (2V)
Abnormal
Replace IC501/ VD501~VD504
Page 18 of 24

22. One color Missing ( Red / Blue / Green )
Chassis : Venus-1BST
One color Missing ( Red / Blue / Green )
VOLTAGE CHART
IC501 VIDEO IC TDA6107JF
Pin 1 : 2.35V DC
Pin 2 : 2.35V DC
Pin 3 : 2.1V DC
Pin 4 : 0V (GND)
Pin 5 : 3.8V DC
Pin 6 : 182V DC
Pin 7 : 162V DC
Pin 8 : 155V DC
Pin 9 : 159V DC
Check CRT base RGB pin dry solder
Abnormal
Touch-up and check
Normal
Check Video IC IC501 dry solder
Abnormal
Touch-up and check
Normal
Check R,G,B i/p on CRT connector XP501 ( 2.2V)
Normal
Replace Video IC IC501 and check
Abnormal
Abnormal
Check Continuity Connector Xp501 to Xp201 on main PCB
Replace and check
Normal
Burning of R285 , R286 , R287
Abnormal
Replace and check
Normal
Check voltage at micon pin 44,45,46 ( 2.1 V)
Abnormal
Micon replace and check
Page 19 of 24

23. AV Mode No Color & No Picture
Chassis : Venus-1BST
AV Mode No Color & No Picture
Check for faulty instrument
e.g. DVD, Setup box, AV cable
Abnormal
Replace the instrument
Normal
Check AV board for dry or track cut.
Abnormal
Touchup & resolder
Normal
Check voltage at C221 at micon Pin no ( 2V)
Abnormal
Replace and check C221
Normal
Check AV Socket to C221 track
(any track cut present)
Normal
Abnormal
Check Crystal X201 dry solder
Replace and check X201
Normal
Replace Micon and check
Page 20 of 24

24. RF Mode Intermittent No color
Chassis : Venus-1BST
RF Mode No color
RF Mode Intermittent No color
Check Color System Auto / Pal
Abnormal
Change System to
(Auto / Pal)
Normal
Check pin no. 24 & 25 of micon
( 1.6V )
Replace Tuner and check
Normal
Abnormal
Check Crystal X201 dry solder
Replace and check X201
Normal
Micon faulty Replace and check
Page 21 of 24

25. Defocus Picture Chassis : Venus-1BST VOLTAGE CHART FBT Page 22 of 24
Pin : 274.5V AC
: 20.37V DC
Pin 2(+B) : 0V (GND) AC
: 108.5V DC
Pin 3(V+) : 41.19V AC
: 0V DC
Pin 4(v-) : 30.46V AC
: 0.13V DC
Pin 5(GND) :
Pin 6(Heater) : 7.10V AC
Pin : 41.85V AC
: 80mV DC
Pin 8(ABL) : 2.16V AC
: 6.27V DC
Pin :
Pin 10 (180V) : 23.1V AC
FBT (T444) adjust upper (focus pot) without disturbing the lower pot.
Normal
Check for focus wire fitment & CRT socket.
Normal
Replace Chassis to confirm CPT or Chassis problem
Abnormal
If CPT then replace CPT else once again Check the chassis
Abnormal
-Check FBT
-Check for Convergence(Menu Display)
-Check for RGB cut-off (in black & white pic.)
-Adjust Contrast & Brightness in user mode &
if not then in SVC mode.
Page 22 of 24

26. Color Patch Chassis : Venus-1BST AUTO DEGAUSSING ABILITY CHECKING
Create little patch by External degaussing coil
Switch off the set for 15~20 min.
Switch on set after 20 min.
Check No patch should be there.
If still patch is there open back cover and check D. coil connector
Insert connector properly and check OK
Try to remove patch with external degaussing coil.
Check Auto Degaussing ability of set
Abnormal
Check for magnetic device nearby (e.g. external speaker, metal parts, etc.)
Abnormal
Remove magnetic devices
Check for degaussing connector fitment, PTC, D coil , relay & also for dry solder.
Replace Part
Normal
Use CPT magnet strip as mentioned in procedure.
Abnormal
Abnormal
If still not then follow complete procedure for Patch removal.
Replace CPT
Page 23 of 24

27. Remote not operate Chassis : Venus-1BST Page 24 of 24 Abnormal
Check for panel key stucking & battery(spring contact)
Abnormal
Change the battery
Normal
Abnormal
Check TV functioning with SVC remote
Check connector XPC11
Abnormal
Replace connector
Normal
Normal
Check for remote PCB ckt. else change the remote
Check IR sensor RM901A
( Pin-1 : 5V , Pin-2 : GND, Pin-3 : 4~5V)
Abnormal
Replace RM901A if still not then check voltage at micon pin 39 (4~5v)
Abnormal
Replace Moicon
Page 24 of 24