LOEWE 5270ZW XELOS
Instrukcja Serwisowa

Note on electrostatic shielding
1. Electrostatically shielded MOS workstations Components sensitive to electrostatic discharge must be handled at workstation with electrostatic shielding. An electrostatically shielded MOS workstation is fitted with discharge resistor which earth all conductive materials, including the technician working there. Dielectrics are discharged by air ionisation. The use of soldering irons and measuring equipment at shielded workstation is only possible in conjunction with isolating transformer in each of the devices used. Measuring equipment chassis are also earthed with discharge resistors. 2. Shielded packaging using conductive materials To protect against electrostatic charges, electrically conductive plastics are used for packaging and transport purposes. Conductive plastics are available in the form of transparent protective bags, foam plastic, film sheeting or containers. Sensitive components requiring the use of protective packaging must only be packed and unpacked at shielded workstations.

Measuring high voltage
1. Set the brightness to minimum. 2. Measure the high voltage. The meter should indicate 29.0kV ± 0.7kV if the meter indication is out of tolerance, immediate service and correction is required to prevent the possibility of premature component failure. 3. To prevent any X-Radiation possibility, it is essential to use the specified tube. NOTE: It is important to use an accurate periodically calibrated high voltage meter.

5. Fit the four extension leads to the signal board making sure that the signal board does not touch the basic board (fig. 8). 6. After servicing ensure all wiring is returned to its original position and fixed. Note: The extension lead wire kit is supplied as a service kit. (Part number 291-90274.920 & 171-90314.999).



Repair information for the signal board Q 4100

There is any error on the signal board, please proceed as described:

Rear panel removal
Unscrew the five rear panel screws R to remove the rear panel. Insert screw driver into recess V. Depress interlocking and at the same time slide rear panel to the rear (fig. 1).

Safety warnings/regulations
1. The repair, modification and testing of mains-operated electronic devices and their accessories must only be performed by qualified persons. 2. It is necessary to follow the regulations and safety warnings to VDE 0701, part 200, as well as the regulations and safety warnings applicable in the country concerned. 3. VDE 0701, Part 2, contains regulations on the repair, modification and testing of mains-operated electronic devices and their accessories. 4. Before delivery, the device and the connecting leads (including any protective earth conductor fitted) must undergo visual inspection, and the insulation resistance and the equivalent leakage current must be measured according to VDE 0701, part 200. The low-resistance continuity of the protective earth conductor must be verified by measurement to VDE regulation 0701, part 1. 5. The regulations of the country concerned must also be observed. 6. Only genuine parts must be used for replacing components marked with the symbol .

How to move the chassis into the service position
1. Hold and lift the rear of the chassis and gently pull the chassis toward you (fig. 2). 2. Undo the cable fixtures. Turn the chassis through 90°anticlockwise and place the chassis behind the set (fig. 3). 3. After servicing ensure all wiring is returned to its original position and fixed.

- Remove the EAROM (I 1941) from the printed circuit board. The TV is able to keep running. - If you get a static picture, the EAROM is out of order (possible geometry errors remain unconsidered). - If the error is still there, it's because of another component on the signal board. - If you want to change the signal board at the service head office in Kronach, insert the EAROM from the damaged signal board into the new one. So you don't need to make the alignment and the programming of the TV set. Important! Please remove the four plastic clamps and the shielding case at the damaged signal board and the AV cover.

Service position for the signal board
1. Remove the signal board from the main chassis (Basic board), ensuring all leads are disconnected. 2. Remove the two screws (A) (fig. 4) from the plastic AV cover and unclip the AV cover from the signal board. 3. Remove the three metal clips (B) (fig. 4) from the metal cover. 4. Unclip the plastic clips (F) at each corner of the front metal cover (fig. 5) and remove from the signal board (fig. 6). Do the same for the rear metal cover (fig. 7).

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