RCA F20TF10, F19425, F19426, F19431, F19436 Service Manual

TX_TVD809

ALIGNMENT PROCEDURES

Operating Conditions

Unless otherwise noted, the following conditions must be observed when aligning the TV:

1.Chassis must be operated from a 120 VAC isolation transformer, with line voltage set to 120 VAC.

2.All voltages and waveforms referenced are with respect to Ground

3.Set Picture Quality controls at nominal (Brightness Saturation at 50% and Contrast at 70%) by using the remote control and pressing “Menu” and select:

◊“2. Picture Quality”

◊“2. Picture Resets”

◊“2. Normal Lighting”

4.A 10X probe must be used for oscilloscope and frequency measurements.

5.Minimum warm-up time is 10 minutes.

Required Test Equipment

Isolation Transformer:

Digital Voltmeter: Range .1V DC to 1000V DC, Accuracy: ±

.5%/

DC Voltage Supply: Range: 0 to 50V, 2A—Well Filtered

Temperature Controlled Soldering Station: Grounded Tip Type—Tip Temperature 500F to 800F Adjustable

NTSC Video Signal Generator: Must provide 1V-P-P Negative Sync, Video into 75-OHM input. Produce, standard NTSC 75% Saturated Color Bars with 100% White Window. (B&K 1249, or equivalent)

RF Signal Generator: 100 kHz to 150 MHz .1V RMS, Int. Mod. 1KHz 30%

Cross Hatch Generator: Must have RF output.

Dual Trace, Delayed Sweep Oscilloscope: 25 MHz with Channel invert capability. Sensitivity’ 5m/V/cm Maximum Sweep Rate: .1us/cm.

POWER SUPPLY ALIGNMENT

1.Insure that input voltage is at 120 VAC, 60Hz.

2.Check that the values RP54, RP56, RP58 and RP59 are the proper values. Connect a voltmeter to “UB” and switch on the set. Voltmeter should indicate that “UB” below 135V. If the voltage at “UB” exceeds 135V, turn the set off immediately and check the values of the power supply circuit components. With “UB” less than 125V proceed to the next step.

3.Tune the set to a channel with a good picture.

4.Set Picture Quality controls at nominal (Brightness Saturation at 50% and Contrast at 70%) by using the remote control and pressing “Menu” and select:

◊“2. Picture Quality”

◊“2. Picture Resets”

◊“2. Normal Lighting”

5.Adjust PP01 (F7) so that the voltage at “UB” is 118.0V+/

-1V.

6.Adjust controls VG2 and Focus on the IHVT (LL05) for

a normal picture.

7.Allow the set to warm up for at least 3 minutes.

8.Set brightness, contrast and volume to minimum.

9.The “UB” voltage should be 118.0V+/-1.5V. If not go back to step1 and re-align the power supply.

TV Service Mode

The service mode is provided to facilitate instrument alignment and service adjustments. The service mode is accessed by pressing a three-button combination on the front control panel of the instrument.

Using the Front Panel Controls to enter Service Mode

1.Turn on the TV and select the channel that will be used for the alignment procedure.

2.With the instrument “ON” press and hold the “VOL2” button and then the “CH+” button, then press and release the “POWER” button.

3.The TV set should immediately display a line menu on the bottom of the screen (see below).

P X	0	V XXX
	S X.XX	4

Service Mode Screen

The Parameter (P) number is on the left side of the display and represents the parameter that will be adjusted. The Value (V) is on the right side of the display and represents the decimal value stored for the function selected. Once the Service Mode Security Code has been entered the CH /\ and CH \/ buttons on the front panel (or the remote transmitter) are used to change the parameter (P) number. The VOL + and VOL - buttons are used to change the decimal value (V) of the function.

NOTE: When the service mode is accessed, the parameter will be “0”. Parameter “0” is used to input the security code. The security code is necessary to protect the factory alignments from inadvertent modification. Attempting to change the parameter (P) using CH /\ or CH \/ before the proper security code has been entered will cause the instrument to exit the service mode. A valid security code is entered (using VOL + or VOL -). The group of XX’s on the second line in the center of the service menu display the software version of the code.

TX_TVD809

ALIGNMENT PROCEDURES

Security Codes

When the Service Mode is first entered, the parameter (P) will come up set at “0”, which corresponds to the security code function.

1.Turn on the TV and select the channel that will be used for the alignment procedure and access the service mode menu.

2.With the parameter (P) set to “0” adjust the value (V) (using VOL + or VOL -) to 76 for access to the Front Panel Service Mode.

3.Once the security code has been set, individual alignments can be accessed by pressing CH /\ or CH \/ changing the parameter (P) number.

4.Once a parameter (P) has been selected for a particular alignment the VOL + and VOL - buttons can be used to change the value (V) of the alignments selected. Parameters available through the front panel are shown in table

5.To exit the service menu, press “POWER” on the remote control or front panel.

P 0	0 V 76
	S X.XX 4

Security Code Entry

Parameter #	Parameter name	Value range		Notes and comments
00	security number	Must be 076		Must not advance to other
				parameters until value set
04	VCO	127(Mono only)
05	AGC	31	(Stereo)
		63	(Mono)
06	Red cut-off	255
07	Green cut-off	255
08	Blue cut-off	255
09	Green Gain	255
10	Blue Gain	255
11	Peak white	52
12	Horizontal phase	31
13	Vertical phase	15
14	Vertical amplitude	63
15	Decoder Input Level	63
16	Decoder _stereo VCO,	63
17	Decoder Filter Setting,	63
18	Decoder_Low_Band,	63
19	Decoder_High_Band,	63
20	Decoder_SAP_VCO,	63
21	S-Video Feature	0 - Disable 1 - Enable		TX809 Stereo Model Only
22	Speaker On/Off Feature	0 - Disable 1 - Enable		TX809 Stereo Model Only
23	Sound Logic Feature	0 - Disable 1 - Enable		TX809 Stereo Model Only
24	Auto Tuning Feature	0 - Disable 1 - Enable		TX809 Stereo Model Only
25	Gemstar OSD Horizontal	185
26	Gemstar OSD Vertical	160

Table 1.

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