Konka KP2905QYT1 User manual

SERVICE MANUAL
Color Television Receiver
Model:KP2905QYT1

IMPORTANT SERVICE SAFETY INFORMATION
Operating the receiver outside of its cabinet or with its back removed involves a shock hazard.
Work on these models should only be performed by those who are thoroughly familiar with
precautions necessary when working on high voltage equipment.
Exercise care when servicing this chassis with power applied. Many B plus and high voltage RF
terminals are exposed which, if carelessly contacted, can cause serious shock or result in damage to
the chassis. Maintain interconnecting ground lead connections between chassis, escutcheon, picture
tube dag and tuner when operating chassis.
These receivers have a “polarized” AC line cord. The AC plug is designed to fit into standard AC
outlets in one direction only. The wide blade connects to the “ground side” and the narrow blade
connects to the hot “side” of the AC line. This assures that the TV receiver is properly grounded to the
house wiring. If an extension cord must be used, make sure it is of the “polarized” type.
Since the chassis of this receive is connected to one side of the AC supply during operation, service
should not be attempted by anyone not familiar with the precautions necessary when working on these
types of equipment.
When it is necessary to make measurements or tests with AC power applied to the receiver
chassis, an Isolation Transformer must be used as a safety precaution and to prevent possible damage
to transistors. The Isolation Transformer should be connected between the TV line cord plug and the
AC power outlet.
Certain High voltage (HV) maybe cause X-ray radiation. Receivers should not be operated with
HV levels exceeding the specified rating for their chassis type. Higher voltage may also increase the
possibility of failure in the HV supply.
It is important to maintain specified values of all components in the horizontal and high voltage
circuits and anywhere else in the receive that could cause a rise in high voltage, or operating supply
voltages. No changes should be made the original design of the receiver.
Components shown in the shaded areas on the schematic diagram and/or identified by in the
replacement parts list should be replaced only with exact factory recommended replacement parts. The
use of unauthorized substitute parts man creats may create shock, fire, X-ray radiation, or other
hazards.
To determine the presence of high voltage, use an accurate high impedance HV meter connected
between the second anode lead and he CRT dag grounding device. When servicing the High Voltage
System remove static charges from it by connecting a 10K Ohm resistor in series Wan insulated
wire(such as test probe) between the picture tube dag and 2nd anode lead(Have AC line cord
disconnected from AC supply).
The picture tube use in this receiver employ integral implosion protection. Replace with a tube of
the same type number for continued safety. Do not lift picture tube by the neck. Handle the picture
tube only when wearing shatterproof goggles and after discharging the high voltage completely, Keep
others without shatter proof goggles away.
Before returning the receiver to the user, perform the following safety checks:
1. Inspect all lead dress to make certain that leads are not pinched or that hardware is not lodged
between the chassis and other metal parts in the receiver.
2. Replace all protective devices such as non-metallic control knobs, insulating fishpapers,
cabinet backs, adjustment and compartment covers of shiedls, isolation resistor-capacitor networks,
mechanical insulators etc.
3. To be sure that not shock hazard exists, a check for the presence of leakage current should be
made at each exposed metal part having a return path to the chassis (antenna, cabinet metal, screw
heads knobs and/or shafts, escutcheon, etc.) in the following manner.
Plug the AC line cord directly into a 220V, AC receptacle. (Do not use an Isolation Transformer
during these checks.) All checks must be repeated with the AC line cord plug connection reversed. (If
necessary, a nonpolarized adapter plug must be used only for the purpose of completing these checks.)

If available, measure current using an accurate leakage current tester. Any reading of 0.35mA or more
is excessive and indicates a potential shock hazard which must be corrected before returning the
receiver to owner.
If a reliable leakage current tester is not available, this allernate method of measurement should
be used. Using two clip leads, connect a 1500 Ohm, 10 watt resistor paralleled by a 0.15MF capacitor
in series with a known earth ground, such as a water pipe or conduit and the metal part to be checked.
Use a VTVM or VOM with 1000 Ohms per Volt, or higher, sensitivity to measure this AC voltage
drop across the resistor,. Any reading of 0.35 volt RMS of more is excessive and indicates potential
shock hazard which must be corrected before returning he receiver to the owner.
ALIGNMENT PROCEDURES
PLEASE READ BEFOREATTEMPTING SERVICE
1. Use an Isolation Transformer when performing any service on this chassis.
2. Never disconnect any leads while receiver is in operation.
3. Disconnect all power before attempting an repairs.
4. Do not short any position of the circuit while the power is on.
5. For safety reasons, replacing any components should be according with identical replacement
parts (SEE PARTS LIST).
6. Before testing, warm up the TV for at least 30 minutes and demagnetize the CRT with an
external degaussing coil.
7. When removing a PCB or related component, after unfastening or changing a wire, be sure to
put the wire back in its original position.
8. Inferior silicon grease can damage IC’s and transistors. When replacing IC’s and transistors,
use only specified silicon grease,. Remove all old silicon when applying new silicon.
9. Before removing the anode cap, discharge eiecticity because it contains high voltage.
10.To adjust MCU N602 installed in the chassis, you should write master slice’s data into this
MCU before installing, and no any data except this test manual listed is admitted to be modified
without designer’s agree.
Test environment
1. Temperature: 15~35°C
2. Relative humidity: 45 ~ 75%
3. Air pressure: 86 ~ 106kPa
TEST EQUIPMENT
1. DC Power Suply (14V)
2. Oscilloscope
3. High Voltage meter 40KV
4. Multi-meter(internal resistance:DC≥20kΩ/V,AC≥5kΩ/V)
5. Ammeter(0.5 grade,DC3mA)
6. Degaussing Coil
7. PHILIP Picture Signal Generator(PH5820 or other type)

Factory menu
1. Press MENU button to display the menu, then press RECALL button five times
continuously to enter factory service menu. Press MENU button to call up FACTORY1-6
after entering into the factory service menu.
2. Press PROG. ▲▼button to select the item (the selected item will turn into red),
then use VOL+/VOL- button to adjust the parameter.
3. Press RECALL button again to exit factory service menu.
IF adjustment
1. Disconnect IF end of RF Tuner.
2. Apply 8V stable power supply to PIN of N954(C963 “+”) input.
3. Connect R108 and R156 joint to GND, apply 5V to XS604 pin1, then connect
Signal generator (PH5820) to IF input (R101 and C101 joint) and apply 95dB 38.9MHz
signal.
4. Connect oscilloscope or digital voltmeter anode to Pin22 of N101, and cathode to
GND, adjust IFT T101 until the measured point level reading on the voltmeter is
2.50±0.05V.(Core inside IFT)
5. Apply 5V to R108 and R156 joint, and connect pin 1 of XS604 to GND, then
apply 95dB 33.9MHz signal. Connect oscilloscope or digital voltmeter anode to Pin22 of
N101, and cathode to GND, adjust RP121 until the measured point level reading on the
voltmeter is 2.50±0.05V.
6. Reconnect IF end.
Check power supply and +B DC adjustment.
1. Check if the AC power supply is normal.
2. Receive TV broadcasting signal and adjust picture to standard mode.
3. Check voltage value between Earth and C910 + that is on the main power PCB
board with DC voltmeter.
4. Then receive traditional TV signal, adjust RP950 to make +B voltage at two end
of C961 meets BOM requirement.
High voltage check and filament voltage check
1. Check AC voltage and +B are within the pointed range before calibrating the
high voltage.
2. Connect high voltmeter to anode of CRT (G4).
3. Turn on the receiver and set Brightness and Contrast to the minimum value.
Swap TV to AV mode (no signal applied)
4. The high voltage must be measured below 35Kv under any mode or brightness
condition, or contrast and Tint are adjusted to the maximum or the minimum value,.
5. Filament voltage must be measured within the range of 6.3±0.2Vrms by virtual
value meter.(Beijing Matsushita Tube)
FOCUS adjustment
1. Receive five circles pattern and adjust the pattern to normal status.

2. Adjust focus potentiometer to obtain the best focus of the pattern.
Horizontal scanning, vertical scanning and geometry correction adjustment
Description: 3 sets of horizontal and vertical parameters need to adjust,
including:Under TV/AV mode, PAL 100i，PAL 75i，NTSC 120I；
Receive five circles pattern signal, then enter into factory menu to call up
FACTROY1.
V SCROLL 0-255
V SIZE 0-255 Adjust it so that the vertical picture reproduction
display ratio is 92%±2%
V SCOR 0-255 Adjust it so that upper pane and bottom pane of the
pattern are the same as the middle pane.
V SHIFT 0-255 Vertical center
V LINEAR 0-255 Vertical linearity
ANGLE 0-255 Parallelogram correction
V ZOOM 0-255 Vertical zoom
Call up FACTORY2
H SIZE 0-255 Adjust it so that the horizontal picture reproduction
display ratio is 92%±2%
H SHIFT 0-255 Adjust pattern horizontal center
A LINE ON/OFF Todisplaya horizontal light line on the pattern. (no
adjustment needed at this time)
UP CORNER 0-255 Adjust it so that vertical lines are straight at upper
corner (left and right). (Receive crosshatch signal)
LOW CORNER 0-255 Adjust it so that vertical lines are straight at low corner
(left and right). (Receive crosshatch signal)
V BOW 0-255 Adjust bow distortion. (Receive crosshatch signal)
TRAPEZIUM 0-255 Adjust trapezium distortion to make it just disappeared.
(Receive crosshatch signal).
PARABOLA 0-255 Adjust Parabola distortion to make it just disappeared.
(Receive crosshatch signal).
H SYNC 0-255 Set to 3 under TV/AV mode。
Call up FACTORY4
NICAM ON
V-EHT 30 （No adjustment）
H-EHT 30 (noadjustment)
HBLANK TIME 0-63 (Adjust horizontal blank time.)
HBLANK PHASE 0-63 (Adjust horizontal blank phase.)
AFCEHT 0
AFCON/OFF ON
PROGRAM NUMB 00 Set program number when turn TV on.