Text preview for : PS42P2SDX_XEC.0000040045.E.09.pdf part of Samsung PS42P2SDX/XEC PLASMA DISPLAY TV service manual
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Troubleshooting
6. Troubleshooting
6-1 Entirely no screen
Remove SMPS output connector (connect Video B d only) Normal
Power on
Abnormal
5V Output
Normal
Replace Video B d
Normal
Abnormal
SMPS Output Voltage Normal Logic Connect Power
Abnormal
AC Input Normal Replace SMPS
Normal
Change Fuse
LED Light-on (Power, Sink) Normal X-B d Connect Power
Abnormal
Replace Logic B d
X-B d Output
Abnormal
Replace X-B d
Normal Y-B d Connect Power
Y-B d Output
Abnormal
Replace Y-B d
Normal Replace Panel
Samsung Electronics
6-1
Alignment and Adjustments
6-2 Partly no screen
Power on
Upper part no screen
Yes
Replace Upper Scan Buffer B d
No
Lower part no scree
Yes
Replace Lower Scan Buffer B d
No
1//14 Screen part Abnormal
Yes
Replace Corresponding Address Buffer B d
No Yes
1/28 no screen
Replace Panel
No Yes
1/7 no screen
Replace Panel
6-2
Samsung Electronics
Troubleshooting
6-3 Checking the Board (Unit)
6-3-1 Y buffer
- To check the main board, you have to check the Y buffer first. - After separating Y Main and Y buffer board, - Check the Diode between OUTL and OUTH, and make sure that the forward voltage drop is between 0.4 and 0.5V.
- Check that the resistance between the two terminals is more than several kW.
Samsung Electronics
6-3
Troubleshooting
6-3-2 Y Main
- After connecting Y main and Y buffer board, check that one of the output waveforms from OUT 1, 2, 3 or 4 is the same as that of the appendix 1 when power is supplied.
6-4
Samsung Electronics
Troubleshooting
6-3-3 X Board
- Check that one of the output waveforms from X-OUT 1 or 2 is the same as that of the appendix 2 when power is supplied.
X- OUT1
X- OUT1
Samsung Electronics
6-5
Troubleshooting
6-3-4 SMPS
- Check output voltage. - If output voltage is not detected, check the following lists: (1) Check fuse (2) In case of +5V(D), check that D305 is short (3) In case of VSAMP, check that D506 is short (4) In case of VA, check that D303 is short (5) In case of VS, check that pin 2 and 3 of Q303 are short (6) In case of Q6S, check that pin 2 and 3 are short (7) Check that BRD101S is short
6-6
Samsung Electronics
Troubleshooting
6-3-5 Scaler Borad
1. PW364 Input Clock (1) MCKEXT Check IC406(IC502) pin 5. Power on : MCKEXT = 97.5MHz Standby : MCKEXT = 48.75MHz (2) MCKEXT, DCKEXT Check IC407(ICS502) pin 25. DCKEXT = 65MHz (3) VCLK Check IC203(SDA9400) pin 26. VCLK = 27MHz (4) GCLK Check IC401(AD9884) pin 115(TP404). GCLK is differently seen according to PC input signal format(VGA, SVGA, XGA) GCLK = 15MHz ~ 50MHz(This value is apparently half of the clock frequency of the relevant PC input signal format.
2. VPC3230 - Check power is supplied(5V, 3.3V). - Check Reset(pin 15) is high. - Check I2C-bus(pins 13, 14) - Check the signal input to Y signal(pin73), C signal(pin 71), PLL DVD-Y signal (pin 72). - Check the output clocks LLC1(pin 28), LLC2(pin 27). (LLC1 = 13.5MHz, LLC2 = 27MHz) - Check the output H sync(pin 56) and check V sync(pin 57) is output. - Check output digital data.
3. SDA9400 - Check power is supplied(3.3V). - Check Reset(pin 30) is high. - Check I2C-bus(pins 20, 21) - Check clock is input.(pins 28, 54 : 27MHz. pin 29 : 13.5MHz) - Check digital data input. - Check the input H sync (pin 23) = 15.75MHz, V sync (pin 22) = 60Hz - Check digital data input. - Check the output H sync (pin 60) = 31.5KHz, V sync (pin 61) = 60Hz, VCLK (pin 26) = 27MHz
4. AD9884(IC101) - Check power is supplied(3.3V) - Check I2C-bus(pins 29, 30) - Check PC signal, HD-component signal is input. - Check the input signal GREF (pin 40). The GREF signal applies to a fixed form of the input H sync signal. - Check the output signal GFBK (pin 117). The GFBK signal applies to a fixed form of PLLD H sync signal. - Check the output signal GCLK (pin 115). The GCLK is differently seen according to the PC input signal format(VGA, SVGA, XGA). GCLK = 15MHz ~ 50MHz This value is apparently half of the clock frequency of the relevant PC input signal format. - Check digital data output.
Samsung Electronics
6-7
Troubleshooting
5. AD9884(IC801) - Check power is supplied(3.3V). - Check I2C-bus(pins 29, 30) - Check Video signal is input. - Check the input signal 2HS (pin 40 or TP406) - Check the output signal VHS (pin 117 or TP409) - Check the output signal VCLK (pin 115 or TP408) - Check digital data input.
6. PW364 Reset - When the Reset switch is pressed. if OTP01(29LV160T) pin 28(TP151) undergoes ransition. PW364 operates and OTP01 also does. Unless transition happens, it means PW364 is not operating.
7. PW364 Communication - Operate the PC hyper terminal Settings are as follows : Model Selection : Direct connect to com1 No. of Bit per second : 57600 Data Bit : 8 Parity : None Stop Bit : 1 Flow Control : None - Whenever the Reset switch is pressed, the following is displayed on the PC hyper terminal screen. CBooter V1.5 & 2000.01.26 CBooter V1.5 & 2000.01.26 CBooter V1.5 & 2000.01.26
6-8
Samsung Electronics