13
105S2 CM23 GSIII
Warning and Notes
3.3 Be careful when taking measurements in the high-voltage section
and on the picture tube panel.
3.4 Never replace modules or other components while the unit is
switched on.
3.5 When making settings, use plastic rather than metal tools.
This will prevent any short-circuit and the danger of a circuit becomes
unstable.
3.6 After repair the wiring should be fastened once more in the cable
clamps for this purpose.
3.7 Together with the deflection unit the picture tube is used as
an integrated unit. Adjustment of this unit during repair is
therefore not recommended.
The semiconductors indicated in the circuit diagram(s) and in the
parts lists are completely interchangeable per position with the
semiconductors in the unit, irrespective of the type indication on
these semiconductors.
4. Notes
Fig. 3.1
V
1. Safety Instructions for Repairs
2. Maintenance Instructions
3. Warnings
1.1 Safety regulations require that during a repair:
- The set should be connected to the mains via an isolating
transformer.
- Safety components, indicated by the symbol
, should be
replaced by components identical to the original ones.
- When replacing the CRT, safety goggles must be worn.
1.2 Safety regulations require also that after a repair:
- The set should be returned in its original condition.
- The cabinet should be checked for defects to avoid touching, by the
customer, of inner parts.
- The insulation of the mains lead should be checked for external
damage.
- The mains lead strain relief should be checked on its function.
- The cableform and EHT cable are routed correctly and fixed with the
mounted cable clamps in order to avoid touching of the CRT, hot
components or heat sinks.
* Thermally loaded solder joints should be checked and resoldered
where necessary. This includes components like LOT, the line
output transistor, fly-back capacitor.
It is recommended to have a maintenance inspection carried out
periodically by a qualified service employee. The interval depends on
the usage conditions.
- During the maintenance inspection the above mentioned "safety
instructions for repair" should be carried out The power supply
and deflection circuitry on the chassis, the CRT panel and the
neck of the CRT should be cleaned.
When cleaning the monitor on the outside:
- Always disconnect the monitor from the mains.
- Always use a damp AND NOT WET lint-free cloth.
- To clean the screen, apply a household glass cleaner to a cloth
and then wipe the screen.
- Do not use solvents or abrasives on the monitor.
It might discolour the cabinet and/or affect the anti glare
treatment on your screen.
3.1 In order to prevent damage to ICs and transistors, all high-
voltage flash-overs must be avoided. In order to prevent damage to
the picture tube, the method shown in Fig 3.1 should be used to
discharge the picture tube. Use a high-voltage probe and a
multimeter (position DC-V). Discharge until the meter reading is 0V
(after approx 30s).
3. 2 ESD
All ICs and many other semiconductors are sensitive to electrostatic
discharges (ESD). Careless handling during repair can drastically
shorten the life. Make sure that during repair you are connected by a
pulse band with resistance to the same potential as the earth of the
unit. Keep components and tools also at this same potential.
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