Service manual

Edition 101222
-- 27 -- s1Cad160
SERVICE INSTRUCTIONS
What is ESD?
A sudden transfer or discharge of static electricity from one object to another. ESD stands for
Electrostatic Discharge.
How does ESD damage occur?
ESD can cause damage to sensitive electrical components, but is not dangerous to people.
ESD damage occurs when an ungrounded person or object with a static charge comes into
contact with a component or assembly that is grounded. A rapid discharge can occur,
causing damage. This damage can take the form of immediate failure, but it is more likely
that system performance will be affected and the component will fail prematurely.
How do we prevent ESD damage?
ESD damage can be prevented by awareness. If static electricity is prevented from building
up on you or on anything at your work station, then there cannot be any static discharges.
Nonconductive materials (e.g. fabrics), or insulators (e.g. plastics) generate and hold static
charge, so you should not bring unnecessary nonconductive items into the work area.
It is obviously difficult to avoid all such items, so various means are used to drain off any
static discharge from persons to prevent the risk of ESD damage. This is done by simple
devices: wrist straps, connected to ground, and conductive shoes.
Work surfaces, carts and containers must be conductive and grounded, use only antistatic
packaging materials. Overall, handling of ESD--sensitive devices should be minimized to
prevent damage.
WARNING !
STATIC ELECTRICITY can damage circuit
boards and electronic components.
S
SS
S Observe precautions for handling electrostatic
sensitive devices.
S
SS
S Use proper static--proof bags and boxes.
ESD
Before the service work
WARNING !
High DC voltage may remain on the electrolytic capaci-
tors on the power board.
Check the voltage and discharge capacitors if needed.
Disconnect the equipment from the mains before opening the housing.
The capacitors of the PFC filters are charged up to 400V and collect significant charge. It is
recommended to wait 5 min. after switching the equipment off and disconnecting it from
mains. This time may include the time of unscrewing all screws of the housing.
Check the voltage on the capacitors on the X8 pads. Openings have standard 2,0mm
diameter as standard multimeter’s probes.
If accelerated discharge of the high voltage is required use 10kW 5W resistor with safe
outlets (i.e. cables with 2,0 mm probes). Note that the time constant is still 15 s.