TOSHIBA 2151TB
Service Manual

TOSHIBA 2151 TB
General Information Chassis : C4E-R

1
Substitute replacement components which do not have the same safety characteristics as specified in the parts list may create X-ray radiation 2. Adjust HEIGHT Control (R351) so that white blocks at top and bottom of the picture are are just masked. HORIZONTAL CENTRE ADJUSTMENT CUT OFF Controls to obtain a good white balance in both low and high light areas. SUB-BRIGHTNESS ADJUSTMENT 1. Tune in a colour programme of Philips pattern. 2. Set the CONTRAST Control to the minimum and the BRIGHTNESS Control to the centre. 3. Set the COLOUR Control to the minimum. 4. Set the SUB-BRIGHT. Control (R551) so that the voltage across terminals Y-Z can be 0.2 ± 0.05V with voltmeter and leave the receiver for five minutes in this state. 5. Watching the picture well, adjust the SUBBRIGHT. Control in the position where the picture does not show evidence of blooming in high bright area and not appear too dark in low bright portion. 6. Check the proper picture variation by rotating the CONTRAST and BRIGHTNESS Controls to both extremes. 7. If the picture does not appear dark with the CONTRAST and BRIGHTNESS Controls turned to the minimum, or not appear bright with the controls turned to the maximum, adjust the SUB-BRIGHT. Control again for the acceptable picture. BUS DATA SETTING 1. In the TV set of initial lot of production, SAA5290ZP/024 is used for QA01. But replace with SAA5290ZP/032 for servicing. 2. When QA01 only is replaced, it is not necessary to change the mode data. 3. When memory IC (QA02) is replaced, change the mode data in the manner below.

Service Adjustments Safety Instructions
X-RAY RADIATION PRECAUTION 1. The E.H.T. must be checked every time the receiver is serviced to ensure that the C.R.T. does not emit X-ray radiation as result of excessive E.H.T. voltage. The nominal E.H.T. for this receiver is 29.8 kV at zero beam current (minimum brightness) operating at 240V a.c. The maximum E.H.T. voltage permissible in any operating circumstances must not exceed 31.5 kV. When checking the E.H.T., use the �High Voltage Check� procedure in this manual using an accurate E.H.T. voltmeter. 2. The only source of X-RAY radiation in this receiver is the C.R.T. To prevent X-ray radiation, the replacement C.R.T. must be identical to the original fitted as specified in the Parts List. 3. Some components used in this receiver have safety related characteristics preventing the C.R.T. from emitting X-ray radiation. For continued safety, replacement component should only be made after referring the Product Safety Notice. SAFETY PRECAUTION 1. This receiver has a nominal working E.H.T. voltage of 26.0 kV. Extreme caution should be exercised when working on the receiver with the back removed. Do not attempt to service this receiver if you are not conversant with the precautions and procedures for working on high voltage equipment. When handling or working on the C.R.T., always discharge the anode to the receiver chassis before removing the anode cap. The C.R.T., if broken, will violently expel glass fragments. Use shatter proof goggles and take extreme care while handling. Do not hold the C.R.T. by the neck as this is a very dangerous practice. 2. It is essential that to maintain the safety of the customer all cable forms be replaced exactly as supplied from factory. 3. A small part of the chassis used in this receiver is, when operating, at approximately half mains potential at all times. It is therefore essential in the interest of safety that when serving or connecting any test equipment the receiver should be supplied via a suitable isolating transformer of adequate rating. 4. Replace blown fuses within the receiver with the fuse specified in the parts list. 5. When replacing wires or components to terminals or tags, wind the leads around the terminal before soldering. When replacing safety components identified by the international hazard symbols on the circuit diagram and parts list, it must be a Toshiba approved type and must be mounted as the original. 6. Keep wires away from high temperature components. PRODUCT SAFETY NOTICE Many electrical and mechanical components in this chassis have special safety-related characteristics. These characteristics are often passed unnoticed by a visual inspection and the X-ray radiation protection afforded by them cannot necessarily be obtained by using replacements rated at higher voltages or wattage, etc. Components which have these special safety characteristics in this manual and its supplements are identified by the international hazard symbols on the schematic diagram and parts list. Before replacing any of these components read the parts list carefully. GENERAL INFORMATION All adjustments are thoroughly checked and corrected when the receiver leaves the factory. Therefore the receiver should operate normally and produce proper colour and B/W pictures upon installation. However, several minor adjustments may be required depending on the particular location in which the receiver is operated. This receiver is shipped completely in cardboard carton. Carefully draw out the receiver from the carton and remove all packing materials. Plug the power cord into a convenient 240 volts 50 Hz AC two pin power outlet. Turn the receiver ON. Check and adjust all the customer controls such as BRIGHTNESS, CONTRAST and COLOUR Controls to obtain natural colour or B/ W picture. AUTOMATIC DEGAUSSING A degaussing coil is mounted around the picture tube so that external degaussing after moving the receiver is normally unnecessary, providing the receiver is properly degaussed upon installation. The degaussing coil operates for about 1 second after the power to the receiver is switched ON. If the set is moved or faced in a different direction, the power switch must be switched off at least 30 minutes in order that the automatic degaussing circuit operates properly. Should the chassis or parts of the cabinet become magnetized to cause poor colour purity, use an external degaussing coil. Slowly move the degaussing coil around the faceplate of the picture tube, the sides and front of the receiver and slowly withdraw the coil to a distance of about 2 m before disconnecting it from AC source. If colour shading still persists, perform the COLOUR PURITY ADJUSTMENT and CONVERGENCE ADJUSTMENTS procedures. HIGH VOLTAGE CHECK 1. Tune the set to the strongest station in your area. 2. Turn AGC DELAY Control (R151) on PIF Board to fully counterclockwise position. 3. Adjust AGC DELAY Control clockwise until noise (snow) disappears on the screen. CRT GREY SCALE ADJUSTMENT 1. Press VIDEO INPUT button on Remote Control unit to turn TV to video input mode. Next press PICTURE SELECT button to select function and set CONTRAST to minimum, BRIGHTNESS to maximum, COLOUR to minimum. 2. Turn the SCREEN Control (on T461) fully counterclockwise. 3. Set the RED, GREEN and BLUE CUT OFF Controls (R557, R558, R559) counterclockwise to the centre position. 4. Set the CUT OFF SW. (S202) in the H. line position. 5. Set the SUB BRIGHTNESS Control to minimum. 6. Rotate the SCREEN Control gradually clockwise until the first horizontal line of a colour (RED, GREEN or BLUE) appears 1. Connect an accurate high voltage meter to the second anode of the picture tube. 2. Turn on the receiver. Set the BRIGHTNESS and CONTRAST Controls to minimum (zero beam current). 3. High voltage will be measured below 31.5kV. 4. Change the BRIGHTNESS Control to both extremes to be sure the high voltage does not exceed the limit of 29.0 kV under any conditions. HEIGHT ADJUSTMENT 1. Receive the WG PHILIPS pattern, and set the contrast and colour to minimum, and the brightness to centre. slightly on the screen. Set the SCREEN Control to this position. 7. Adjust the CUT OFF Controls to obtain the slightly lighted horizontal lines in the same levels of three colours (RED, GREEN and BLUE). The lines may look like white if the CUT OFF Controls are adjusted properly. 8. Return the CUT OFF SW. (S202) in the receiving position. 9. Set the BRIGHTNESS Control to the maximum and COLOUR Control to the centre. 10.Set the BRIGHTNESS and CONTRAST Controls to obtain dark grey raster. Then check the white balance in low brightness. If the white balance is not proper, retouch the 1. Receive the UK PHILIPS pattern. 2. Set the contrast and colour to centre, and the brightness to centre. 3. Adjust H. CENTER USER Control (R451) so the pattern can be located for d-c to be + 4.0 mm.

Example of screen display in level adjustment PICTURE I-F ALIGNMENT GENERAL Refer to figure 4 for test equipment connection. PRELIMINARY STEPS Supply +5 volts to the 5V-1 line. SIGNAL GENERATOR Connect to both leads of R101 with signal level of 75 dBµ, and open the solder-link at IF OUT of tuner on the Main Board. (See figure 4.) DVM Connect to pin #44 of 1C501 on the Main Board through the detector.

FOCUS ADJUSTMENT Adjust FOCUS Control on FLYBACK TRANS. (T461) for well defined scanning lines in the centre area on the screen. DELAYED R-F AGC ADJUSTMENT

ADJUSTMENT METHOD FOR SERVICING 1.OUTLINE In the service mode, MODE DATA adjustments can be made easily with user remote control unit. (CT-9689 only) 2.SERVICE MODE OPERATION 2-1. How to Enter the Service Mode

Figure 4. Picture IF Alignment STEP Detector Coil SIGNAL GENERATOR 39.5 MHz CARRIER WAVE (Level 75 dBµ) ADJUST T103 REMARKS 1. Supply external DC power (+ 5V) to 5V-1 line. 2. Supply + 8V to pin 36 of IC501. 3. Supply external DC power to + 12V line. 4. Apply test signal to IF input. 5. Adjust T103 so that DC voltage at pin 44 of IC501 becomes 3.2V ± 0.5V. After completing the above steps, disconnect the equipment and re-solder the links on the Main Board, and adjust the AGC Delay control

Recommended Safety Parts
Item
C440 C444 C463 C801 C802 C803 R327 R444 R448 R801 R844 R890 R920 L462 L901 T401 T461 T801 T803 Q404 Q826 Q835 F801 F803 P801 S801 V901 V901A

Part No.
24082343 24082336 24212222 24082363 24094656 24094656 24339569 24338398 24338338 24009954 24005007 24019340 24000568 -----------23200205 23224983 23236464 23211858 23217240 23314375 A8643108 23318299 23144898 23144875 23372012 23145434 23312670 23902891

Description
PF, 5600pF, ±3%, 1500V PF, 3600pF, ±3%, 1500V CD, 2200pF, ±10% PE, 0.22µF, ±20%, AC250V CD, 2200pF, ±20%, AC400V CD, 2200pF, ±20%, AC400V ME, 5.6 ohm, 2W ME, 0.39 ohm, 1W ME, 0.33 ohm, 1W Metal-Glazed Resistor, 2.2M ohm, 1/2W Metal-Glazed Resistor, 8.2M ohm, 1W PTC Thermistor, 18 ohm, 290V FR, 4.7 ohm, 1W DY, Supplied with V901 Coil, Degaussing, TSB-2333AR Transformer, Horiz. Drive, TLN1039 Transformer, Flyback, TFB41 23AR Line Filter, TRF3139 Transformer, Converter, TPW3301AR Transistor, ON4409(508D) Photo Coupler, TLP621(GR-LF IC, L78MR05 Fuse, 3.15A Fuse, 0.63A Power Cord Switch, Power, 2C2P Picture Tube, A51EAL155X01 Socket, CRT, 10P

CAUTION: There is no HIGH VOLTAGE ADJUSTMENT on this chassis.

2-2. How to Exit from the ServIce Mode Exit the service mode by turning the power on/ off with the remote control. 3. ADJUSTMENT IN THE SERVICE MODE Service Mode Level Adjustments 1) Push + key (simultaneous push) to appear Mode Data to be adjusted. 2) Adjust with the level UP/DOWN (VOL UP/ DOWN) key.

(R151) following DELAYED RF AGC ADJUSTMENTS.

Safety Instructions / Safety Parts / Service Adjustments / Main Diagram / Main Diagram Cont�d