SONY FDL3105
Manual de Servicio

4. Connect an oscilloscope to the TP304 (IC301 Pin 36) blue * output.
CONTRAST ADJUSTMENT

5. Connect an oscilloscope (CHl) to the TP305 (IC301 pin 34) green output and (CH2) to the TP (IC301 pin 36) blue output. 6. Turn RV309 (SUB CONT B) to adjust the blue gain so that the positive polarity red signal step wave coincides with the positive polarity green signal step wave on the oscilloscope. 7. Disconnect pin 46 from pin 33 of IC301, and pin 45 from GND. The positive polarity signal and the negative polarity signal may not simultaneously coincide due to the variation.(Figures a and b) In this case, adjust these signals to an average value. (Figure c)

Procedure: 1. Short between IC301 pin-46 and pin-33, and between pin-45 and GND. (Short them at the same time.) Picture will show the white- compressed picture. 2. Input the 5- to 16-step black and white wave (stairstep) of the pattern generator (75 Sz and 1 Vp-p) to the A/V IN jack (J301). 3. Connect an oscilloscope (DC range 1 V/ DIV) to the TP305 (IC301 pin 34) green output. 4. Adjust RV307 (BRIGHT control) so that the black level obtains - 3.8V (line K).
A : 3.8 !I O.lVp-p

Figure b

Figure c

Negative

u-W
polarity Positive

polarity VIF ADJUSTMENT

5. Adjust RV301 (contrast) so that the white line obtains the GND potential (line M) (A = 3.8 t O.lVp-p). � 6. Disconnect pin 46 from pin 33 of IC301, and pin 45 from GND.

Note: These adjustments are not performed usually. Never

touch CT201 of adjusting device. While, only when CT201 have been replaced, make the following simple adjustment.
- Simple adjustment -

WHITE

BALANCE

ADJUSTMENT

Note: When performing this adjustment, set the direct

current drift .adjustment so that the direct currents on each channel of the oscilloscope is stabilized, and use the oscilloscope in this condition. Procedure: 1. Short between IC301 pin-46 and pin-33, and between pin-45 and GND. (Short them at the same time.) Picture will show the white - compressed picture. 2. Input the 5- to 16-step black and white step wave (stair -step) of the pattern generator (75 Sz and 1 Vp-p) to the A/V IN jack (J301). 3. Connect an oscilloscope (CHl) to the TP305 (IC301 pin 34) green output and (CHZ) to the TP504 (IC301 pin 32) red output. 4. Turn RV308 (SUB CONT R) to adjust the red gain so that the positive polarity red signal step wave coincides with the positive polarity green signal step wave on the oscilloscope. -7-

Procedure: Input the monochromatic gradation .wave from EXT ANT IN jack (JlOl). Connect an oscilloscope to Q314 emitter. Adjust CT201 so that the synchro signal is maximum (VIF adjustment). Receive the broadcasts of 2 to 13ch, and check if the screen is colored after the synchronism is stopped with each channel.

To / make maximum (VIF adjustment)

synchro chip