CRT:CT-20D20

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Revision as of 07:39, 22 May 2022 by ApolloBoy (talk | contribs) (Added instructions on accessing the service menu and sections on the service adjustments. These were sourced from a service manual for another Panasonic CRT and verified on my set)
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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
Component No
Dimensions Width: 571.5 mm

Depth: 457.2 mm

Height: 469.9 mm
Earliest Date c. 2000
Links
Operation Manual CT-20D20 Operating Instructions

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.