Philips 20LW202222 free download

File name 20LW202222 20L800 SERVICE MANUAL 7602.pdf

Philips Consumer Electronics Technical Service Data Service and Quality Service Publications Dept. One Philips Drive P.O. Box 14810 Knoxville, TN 37914 Manual 7602 Model no.: 20LW202222 First Publish: 5-10-2001 Rev. Date: 10-16-2002 Print Date: 19/11/2005 Electrical Adjustments REFER TO SAFETY GUIDELINES SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES. CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING © Philips Electronics North America Corporation Visit our World Wide Web Site at http://www.forceonline.com Alignments Note: The Service Default Mode (SDM) and Service Alignment Mode (SAM) are described in Service Modes Error Codes And Fault Finding. Menu navigation is done with the 'CURSOR UP, DOWN, LEFT or RIGHT' keys of the remote control transmitter. General Alignment Conditions Perform all electrical adjustments under the following conditions: · · · · · · AC voltage and frequency: 110 V (± 10 %), 60 Hz (± 5 %). Connect the set to the AC power via an isolation transformer. Allow the set to warm up for approximately 20 minutes. Measure the voltages and waveforms in relation to chassis ground (with the exception of the voltages on the primary side of the power supply). Never use the cooling fins / plates as ground. Test probe: Ri > 10 M; Ci < 2.5 pF. Use an isolated trimmer / screwdriver to perform the alignments. Hardware Alignments Fig. 1 Vg2 Adjustment 1. 2. 3. 4. Activate the SAM. Go to the WHITE TONE sub menu. Set the values of NORMAL RED, GREEN and BLUE to 40. Go, via the MENU key, to the normal user menu and set - CONTRAST to zero. - BRIGHTNESS to minimum (OSD just visible in a dark room). 5. Return to the SAM via the MENU key. 6. Connect the RF output of a pattern generator to the antenna input. Test pattern is a 'black' picture (blank screen on CRT without any OSD info). 7. Set the channel of the oscilloscope to 50 V/div and the time base to 0.2 ms (external triggering on the vertical pulse). 8. Ground the scope at the CRT panel and connect a 10:1 probe to one of the cathodes of the picture tube socket (see diagram B). 9. Measure the cut off pulse during first full line after the frame blanking (see Fig. 2). You will see two pulses, one being the cut off pulse and the other being the white drive pulse. Choose the one with the lowest value, this is the cut off pulse. 10. Select the cathode with the highest VDC value for the alignment. Adjust the Vcutoff of this gun with the SCREEN potentiometer (see Fig. 1) on the LOT to the correct value (see table below). 11. Restore BRIGHTNESS and CONTRAST to normal (= 31). Fig. 2 Focusing 1. Tune the set to a circle or crosshatch test pattern (use an external video pattern generator). 2. Choose picture mode NATURAL (or MOVIES) with the 'SMART PICTURE' button on the remote control transmitter. 3