TOSHIBA 14N21D2Y
Manual de Servicio

ELECTRICAL ADJUSTMENTS
1. ADJUSTMENT PROCEDURE
Read and perform these adjustments when repairing the circuits or replacing electrical parts or PCB assemblies. CAUTION � Use an isolation transformer when performing any service on this chassis. � Before removing the anode cap, discharge electricity because it contains high voltage. � When removing a PCB or related component, after unfastening or changing a wire, be sure to put the wire back in its original position. � When you exchange IC and Transistor for a heat sink, apply the silicon grease on the contact section of the heat sink. Before applying new silicon grease, remove all the old silicon grease. (Old grease may cause damages to the IC and Transistor). Prepare the following measurement tools for electrical adjustments. 1. Oscilloscope 2. Digital Voltmeter 3. Pattern Generator On-Screen Display Adjustment 1. In the condition of NO indication on the screen. Press the VOL. DOWN button on the set and the Channel button (9) on the remote control for more than 2 seconds to appear the adjustment mode on the screen as shown in Fig. 1-1. TV

2. BASIC ADJUSTMENTS
2-1: CONSTANT VOLTAGE Place the set with Aging Test for more than 15 minutes. 1. 2. Connect the digital voltmeter to TP502. 3. Set condition is AV MODE without signal. 4. Adjust the VR501 until the DC voltage is 135 ± 0.5V. 2-2: VCO 1. Place the set with Aging Test for more than 10 minutes. 2. Connect the oscillator (38.9MHz) to TP003. 3. Activate the adjustment mode display of Fig. 1-1 and press the channel button (13) on the remote control to select "VCO COARSE". 4. Press the VOL. +/- button on the remote control until the "OK" appear on the screen. If the "OK" is not displayed, select the "+" side on the changed from "+" to "-". 5. Press the Page UP button once to set to "VCO FINE" mode. 6. Press the VOL. +/- button on the remote control to select the 5 step down point from the upper limit on the "OK". (Example: In case of the "OK" range 30~41, select 36.) 2-3: AGC VOLTAGE Place the set with Aging Test for more than 15 minutes. Receive the UHF (63 ± 1dB). Connect the digital voltmeter to TP002. Activate the adjustment mode display of Fig. 1-1 and press the channel button (01) on the remote control to select "RF AGC". 5. Press the VOL. +/- button on the remote control until the digital voltmeter is 2.5 ± 0.05V. 2-4: CUT OFF 1. 2. 3. 4.

35 H. POSI OSD

128 Fig. 1-1

2. Use the Channel button (0-9) or Channel UP/DOWN button on the remote control to select the options shown in Fig. 1-2. 3. Press the MENU button on the remote control to end the adjustments.
NO. 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 FUNCTION CUT OFF RF AGC AGC GAIN R DRIVE R CUTOFF G DRIVE G CUTOFF B DRIVE H POSI (50) V POSI (50) V POSI (60) V SIZE (50) V SIZE (60) VCO COARSE VCO FINE VCO COARSE L1 VCO FINE L1 BRIGHT CENT BRIGHT MAX BRIGHT MIN NO. 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 FUNCTION TINT SHARP CONTRAST CENT CONTRAST MAX CONTRAST MIN COLOR CENT COLOR MAX COLOR MIN M R CUT OFF M G CUT OFF M B CUT OFF CVBS OUT APR THRESHOLD BELL FILTER BANDPASS H POSI OSD V POSI OSD H POSI TEXT V POSI TEXT H POSI (60)

1. Set condition is AV MODE without signal. 2. Using the remote control, set the brightness and contrast to normal position. 3. Place the set with Aging Test for more than 15 minutes. 4. Activate the adjustment mode display of Fig. 1-1 and press the channel button (00) on the remote control to select "CUT OFF". 5. Adjust the Screen Volume until a dim raster is obtained. 2-5: WHITE BALANCE NOTE: Adjust after performing CUT OFF adjustment. 1. Place the set with Aging Test for more than 10 minutes. 2. Receive the gray scale pattern from the Pattern Generator. 3. Using the remote control, set the brightness and contrast to normal position. 4. Activate the adjustment mode display of Fig. 1-1 and press the channel button (03) on the remote control to select "R DRIVE". 5. Press the Page UP/DOWN button on the remote control to select the "R DRIVE", "G DRIVE", "M R CUTOFF" or "M G CUTOFF". 6. Adjust the VOL. +/- button on the remote control to whiten the R DRIVE, G DRIVE, M R CUT OFF, and M G

Fig. 1-2

CUT OFF at each step tone sections equally. 7. Perform the above adjustments 5 and 6 until the white color is looked like a white. D-1