CRT:CT-20D20

CT-20D20

Information
Manufacturer	Panasonic
Type	Consumer
Size	20"
Regions	NTSC
240p/480i	Yes
480p	No
720p	No
1080i	No
Vsync	60 Hz
Widescreen	No
Composite	Yes, two inputs (one front, one rear)
S-Video	Yes, shared with rear composite input
Component	No
Speakers	Stereo
Dimensions	Width: 571.5 mm Depth: 457.2 mm Height: 469.9 mm
Earliest Date	c. 2000
Links
Tube	Panasonic A51KQN011X
Operation Manual	CT-20D20 Operating Instructions

The Panasonic CT-20D20 is a mid-priced 20" consumer CRT first introduced around 2000. It is a well-rounded set featuring stereo speakers, two sets of composite inputs, and an S-video input. Other features include a sleep timer, "surround" sound and even a "game guard" to prevent children from playing video games! Like most Panasonic sets from the early 2000s, the CT-20D20 has a curved slot mask picture tube.

Service Menu

Entering the service menu on the CT-20D20 is fairly similar to other Panasonic CRTs of this vintage. To access the menu, follow these steps:

1. Adjust the volume to 0.
2. Press the Action button on either the set or remote to bring up the menu. Navigate to the Setup section and make sure that the closed caption mode (CC MODE) is OFF.
3. Exit the Setup section and enter the Timer section. Set the sleep timer for 30 minutes.
4. Exit all menus.
5. Tune in to channel 124 and press the Volume Down button on the set (not the remote!) to enter the service menu. A red "CHK" should appear in the upper left corner of the screen.
6. Use the Power button on either the set or remote to go through the various adjustment sections. The Channel buttons go through each adjustment in the section and the Volume buttons are used to make adjustments.

Service Menu Adjustments

Note that the names of the adjustments are inferred from other Panasonic CRTs of this vintage as the service manual for this specific model has not been located yet.

Sub-Data Adjustment

Number	Name	Range	Default
B0	SUB-COLOR	0-63	30
B1	SUB-TINT	0-63	42
B2	SUB-BRIGHTNESS	0-255	35
B3	SUB-PICTURE	0-63	26
B4	KILLER/ABL/GAMMA	0-7	4
B5	VIDEO ADJUSTMENT	0-31	8
B6	AUDIO ADJUSTMENT	0-31	8
B7	V-SIZE	0-63	43

Cut-Off Adjustment

Number	Name	Range	Default
C0	CUT-OFF R	0-255	64
C1	CUT-OFF G	0-255	32
C2	CUT-OFF B	0-255	128
C3	DRIVE R	0-127	32
C4	DRIVE B	0-127	64
C5	YNR SWITCH	0-1	0
C6	AFT	0-225	126
C7	RF-AGC	0-127	64
C8	YNR VIDEO ADJUSTMENT	0-7	0
C9	HORIZONTAL CENTER	0-31	12
Ca	BEAM LIMIT	0-7	4
Cb	VCJ TEST H	0-2	0

Comb Filter Adjustment

Number	Name	Range	Default
X0	COMB GAIN	0-255	152
X1	COMB SWITCH	0-63	12
X2	COMB LIMIT	0-63	24
X3	COMB CORE	0-127	41
X4	COMB RF DELAY	0-127	18
X5	COMB VIDEO DELAY	0-127	18
X6	COMB VMLM	0-127	90
X7	COMB VM SW	0-63	24
X8	COMB SHARP	0-255	30
X9	COMB VM LEVEL	0-255	255
Xa	COMB VMPKF	0-1	1
Xb	COMB ADJ SHARP	0-63	10

Note that the S and M sections of the service menu are for Picture-in-Picture mode and MTS audio which this model does not have, and so can be ignored.

To exit the service menu completely, hold down the Power and Action buttons on the set (not the remote) for at least two seconds. This should reset the TV and a self-test screen will appear. The set will return to normal operation after this.

Purity Field Check Mode

While in the service menu, the color purity of the tube can be easily checked. Press the Recall button on the remote to enter this mode. A white screen will be displayed. Pressing Recall a second time will display a pure red screen, a third time a pure green screen, and a fourth time a pure blue screen. The fifth press will exit the purity check to the regular service menu.

Aging Mode

In addition to the service menu, the CT-20D20 also has an "Aging" mode that can somewhat rejuvenate a picture tube that has seen significant use. To toggle between the service menu and aging mode, press the Action and Volume Up buttons simultaneously on the set (not the remote). The red "CHK" should turn yellow when in aging mode. Press Recall on the remote to activate the aging mode and again to turn it off.