ITT 3721
Service Manual

0 GE3

Service adjustmmts
Other service adjustments
Horizontal amplitude
Adjust 90� CRTs horizontal amplitude with coil LK 12. Adjust 110� SQ and FST - CRT�s with resistor RK66.

Note! Before other adjustments Ul voltage must be adjusted. If the set cannot be switched on with the number buttons, please see under �RC Mode� (Service menu 2). Wait! Allow the TV set to be switched on for 10 minutes before any adjustment.

Service mode
Select the service mode by pressing the Mute, OK (MI and TV buttons in sequence on the remote control unit. Use the blue button to call up the Service Menu 2, 3 (or Service Menu 1 again). Cursor button A or v Cursor button 4 or) OK (M) button TV button = To select required = To adjust it adjustment into the memory.

Vertical position
Adjust vertical position by severing resistor RS24, and/or RS14.

Focus
Use focus adjuster TK02 optimum sharpness. (at horizontal transformer) to set the focus to

= To store the adjustment = To return to normal

TV mode.

Cushion
Adjust 110� SQ and FST CRT�s with resistor RK60.

Service adjustments which are made in service mode
Display Start APS Note Service Menu 1 YES = APS; search function will be run automatically when the set is switched on for the first time and stores all stations into the memory. Adjust the bottom edge. Stereo set: Adjust centre of the test picture horizontaly to a centered position. Mono set: Adjust centre of the test horizontal to a centered position with RK 45. Ul operating voltage, see adj. �Ul voltage�. See adjustment �AGC�. Service Menu 2 Select required standard. Set to approriate television standard. (Remote Control), select the other remote control units. YES, if front AV socket is available. Teletext character sets: OFF, EUtCS, EUtTR, East 1, East 2 Service Menu 3 (only with stereo sets) Equalizer C4 Bit Loudness AVC Carrier Mute Hi-Dev YES/NO ; YES = on Ya$witches back to FM-sound, if FM-sound # Nicam No: Switches Nicam during Nicam-transmission. YES/NO Yes: Supresses sound cracks. Yes: Switches sound off, if carrier missing. Displays �HDM� line in the audio menu, use in case of overmodulation of sound.

G2 and colour temperature
1. Set the UG2 adjustment (the lower adjustment at horizontal transformer) to its middle position. 2. Select the IDEAL picture setting and switch the set to AV programme number or other black screen picture. 3. Using the oscilloscope with 1OO:l probe determine the colour cathode with the highest black level measuring pulse at IC NHOl, pins 9, 12 and 15. 4. Adjust the highest measuring pulse to 150V (measured against ground).

V-Amplitude H-Shift

Ul AGC

AFC
1.Feed in symmetric

IF signal (ca. 0,8 Vpp) by means of 4:l transmitter at test points XL 03 and XL 04. (38,9 MHz for standard BG, DK and 39,5 MHz for standard I) ground) set 3,5 V DC i 0,5 V with coil ZL 01

Set Standard APS Standard RC Mode Front AV Text Characters

2. At test point XL 01 (XL 02 to (AFC reference). 3. Multistandard set, standard channel in band 1 (L�-range). Feed in symmetric IF signal test points XL 03 and XL 04. 01 (XL 02 to ground)

L�: After proper BG adjustment select a Activate standard L in Tuning menu. (ca. 0,8 Vpp) by means of 4:l transmitter at (33,9 MHz for standard L�) At test point XL CL 05.

set 3,5 V DC + 0,5 V with capacitor

AFC check
Detune the IF signal to approx. 39 MHz (39,7 MHz, 34 MHz). Then the voltage must drop to approx. IV.

Sound of multistandard sets (standard BG, DK or standard I)
Make the standard adjustment as follows: 1. RCF remote control unit: Press the PROG button. RCN remote control unit: Press the blue MENU button twice. 2. Select the menu line Tuning, Manual tuning. 3. Select STANDARD BG, DK or I with cursor buttons 4 and ). 4. Store the setting by pressing the OK (M) button. 5. Return to normal TV viewing by pressing the TV button.

Adjustment Ul voltage
1. 2. 3. 4. 5. Set the contrast and brightness to minimum. Connect test point XFOI (chassis board) to ground. Go to service menu 1 (see service mode). Use cursor button A or v to select Ul-adjustment. Adjust with cursor button 4 or) IlOV f IV 14� (Philips/Samtel ) and 20� (Videocolor) 135V i IV 21� (Philips) 150V + IV 25� and 28� (Videocolor) 6. Use OK (M) memory button to store the value into the memory. 7. Remove XFOl/ground connection. 8. Return to normal TV mode by pressing the TV button.

AM sound (multistandard module)
1.Connect

a sweep generator

with 30-40 MHz marking

to pin 14 of AL-

AGC
1. Connect test point XFOl (Chassis board) to ground. 2. Feed in RF signal without sound carrier with 72 dBpV (= 4mV) on a medium UHF channel via the aerial input. 3. Go to service menu 1 (see service mode). 4. Use cursor button A or v to select AGC adjustment. 5. Connect oscilloscope (Bandwidth > 50 MHz) to the tuner�s IF output (test point XL03 or XLO4) and to ground (XLO2). 6. Use cursor button 4 and) to adjust 350 mVpp +O/-50mV with reference to the signal�s synchronizing peaks. 7. Use OK (M) memory button to store the value into the memory. 8. Remove XFOl/ground connection. 9. Return to normal TV mode by pressing the TV button.

connector. 2. Connect an oscilloscope to pin 11 of AL-connector. 3. Connect a control voltage supply to pin 3 of TDA 9830. 4. L standard: The voltage at pin 09 of AL-connector = 0 V. Set the output amplitude to 200 mV by means of the control voltage and keep this value during the adjustment. Adjust the amplitude of 34,2 MHz to maximum with ZL 651 and ZL 652. 5. After proper L-adjustment: L� standard: The voltage at pin 10 of AL-connector = 12 V. Set the output amplitude to 200 mV by means of the control voltage and keep this value during the adjustment. Adjust the amplitude of 40,4 MHz to maximum with RL 673.