1 Safety Precautions
1.1. General Guidelines
1. IMPORTANT SAFETY NOTICE
There re speci l components used in this equipment
which re import nt for s fety. These p rts re m rked by
^ in the Schem tic Di gr ms, Circuit Bo rd L yout,
Exploded Views nd Repl cement P rts List. It is essen
ti l th t these critic l p rts should be repl ced with m nu
f cturer's specified p rts to prevent X-RADIATION,
shock, fire, or other h z rds. Do not modify the origin l
design without permission of m nuf cturer.
2. An Isol tion Tr nsformer should lw ys be used during
the servicing of AC Ad ptor whose ch ssis is not isol ted
from the AC power line. Use tr nsformer of dequ te
power r ting s this protects the technici n from cci
dents resulting in person l injury from electric l shocks. It
will lso protect AC Ad ptor from being d m ged by cci
dent l shorting th t m y occur during servicing.
3. When servicing, observe the origin l le d dress. If short
circuit is found, repl ce ll p rts which h ve been over
he ted or d m ged by the short circuit.
4. After servicing, see to it th t ll the protective devices
such s insul tion b rriers, insul tion p pers shields re
properly inst lled.
5. After servicing, m ke the following le k ge current
checks to prevent the customer from being exposed to
shock h z rds.
1.2. Leakage Current Cold Check
1. Unplug the AC cord nd connect jumper between the
two prongs on the plug.
2. Me sure the resist nce v lue, with n ohmmeter,
between the jumpered AC plug nd e ch exposed met l
lic c binet p rt on the equipment such s screwhe ds,
connectors, control sh fts, etc. When the exposed met l
lic p rt h s return p th to the ch ssis, the re ding
should be between 1 MQ nd 5.2 MQ. When the exposed
met l does not h ve return p th to the ch ssis, the
re ding must be infinity.
1.3. Leakage Current Hot Check
(See Figure 1.)
1. Plug the AC cord directly into the AC outlet. Do not use
n isol tion tr nsformer for this check.
2. Connect 1.5 kQ, 10 W resistor, in p r llel with 0.15 |iF
c p citor, between e ch exposed met llic p rt on the set
nd good e rth ground, s shown in Figure 1.
3. Use n AC voltmeter, with 1 kQ/V or more sensitivity, to
me sure the potenti l cross the resistor.
4. Check e ch exposed met llic p rt, nd me sure the volt
ge t e ch point.
5. Reverse the AC plug in the AC outlet nd repe t e ch of
the bove me surements.
6. The potenti l t ny point should not exceed 0.75 V RMS.
A le k ge current tester (Simpson Model 229 or equiv
lent) m y be used to m ke the hot checks, le k ge cur
rent must not exceed 1/2 mA. In c se me surement is
outside of the limits specified, there is possibility of
shock h z rd, nd the equipment should be rep ired nd
rechecked before it is returned to the customer.
1.5 kQ. 10 W
Figure. 1
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