Note on electrostatic shieldingRear panel removal+Repair information for the signal board
1. Electrostatically shielded MOS workstationsUnscrew the five rear panel screR to remows ve the rear panel.MediaPlus
Components sensitive to electrostatic discharge must beInsert screw driver into recess V. Depress interlocking and at theThere is any error on the signal board, please proceed as de-
same time slide rear panel to the rear (fig. 1).
handled at workstation with electrostatic shielding. An elec-scribed:
trostatically shielded MOS workstation is fitted with discharge
resistor which earth all conductive materials, including the- Remove the EAROM (I 1891) from the printed circuit board. The
technician working there. Dielectrics are discharged by airTV is able to keep running.
ionisation. The use of soldering irons and measurHoing equip-w to move the chassis into the service position
- If you get a static picture, the EAROM is out of order (possible
ment at shielded workstation is only possible in conjunction
1. Hold and lift the rear of the chassis and gently pull the chas-geometry errors remain unconsidered).
with isolating transformer in each of the devices used. Meas-
sis toward you (fig. 2).
uring equipment chassis are also earthed with discharge re-- If the error is still there, it's because of another component on
sistors.2. Undo the cable fixtures. Turn the chassis through 90°anti-the signal board.
clockwise and place the chassis behind the set (fig. 3).
- If you want to change the signal board at the service head office
3. After servicing ensure all wiring is returned to its orin Kronach, insert the EAROM from the damaged signal boardiginal po-
2. Shielded packaging using conductive materials
sition and fixed.into the new one. So you don't need to make the alignment and
To protect against electrostatic charges, electrically conduc-the programming of the TV set.
tive plastics are used for packaging and transport purposes.
Conductive plastics are available in the form of transparent
Important!
protective bags, foam plastic, film sheeting or containers.
Service position for the signal boardPlease remove the AV cover at the damaged signal board.
Sensitive components requiring the use of protective pack-
aging must only be packed and unpacked at shielded w1. Remoorkve the signal board from the main chassis (Basic board),-
stations.ensuring all leads are disconnected.
2. Remove the four screws (A) (fig. 4) from the plastic AV cover
and unclip the AV cover from the signal board.
3. Remove the front metal cover from the signal board (fig. 5).
Do the same for the rear metal cover (fig. 6).
Safety warnings/regulations
4. Fit the three extension leads to the signal board making sure
1. The repair, modification and testing of mains-operthat the signal board does not touch the basic board (fig. 7).ated elec-
tronic devices and their accessories must only be performed
5. After servicing ensure all wiring is returned to its original po-
by qualified persons.
sition and fixed.
2. It is necessary to follow the regulations and safety warnings
Note:
to VDE 0701, part 200, as well as the regulations and safety
The extension lead wire kit is supplied as a service kit. (Part
warnings applicable in the country concerned.
number 291-90274.920).
3. VDE 0701, Part 2, contains regulations on the repair, modifi-
cation and testing of mains-operated electronic devices and
their accessories.
4. Before delivery, the device and the connecting leads (includ-
ing any protective earth conductor fitted) must undergo visu-
al inspection, and the insulation resistance and the equiva-
lent leakage current must be measured according to VDE
0701, part 200. The low-resistance continuity of the protec-
tive earth conductor must be verified by measurement to VDE
regulation 0701, part 1.
5. The regulations of the country concerned must also be ob-
served.
6. Only genuine parts must be used for replacing components
marked with the symbol . |
ACEC
