Hitachi DV-PF2U, Service Manual

Page: 8 / 97

1-4-2
Chassis or Secondary Conductor
d d'
Primary Circuit Terminals
AC Voltmeter
(High Impedance)
Exposed Accessible Part
B
Earth Ground
Power Cord Plug Prongs
Z
1.5k
0.15 F
Safety Check after Servicing
Examine the area surrounding the repaired location for
damage or deterioration. Observe that screws, parts,
and wires have been returned to their original posi-
tions. Afterwards, do the following tests and confirm
the specified values to verify compliance with safety
standards.
1. Clearance Distance
When replacing primary circuit components, confirm
specified clearance distance (d) and (d’) between sol-
dered terminals, and between terminals and surround-
ing metallic parts. (See Fig. 1)
Table 1 : Ratings for selected area
Note: This table is unofficial and for reference only.
Be sure to confirm the precise values.
2. Leakage Current Test
Confirm the specified (or lower) leakage current
between B (earth ground, power cord plug prongs)
and externally exposed accessible parts (RF termi-
nals, antenna terminals, video and audio input and
output terminals, microphone jacks, earphone jacks,
etc.) is lower than or equal to the specified value in the
table below.
Measuring Method (Power ON) :
Insert load Z between B (earth ground, power cord
plug prongs) and exposed accessible parts. Use an
AC voltmeter to measure across the terminals of load
Z. See Fig. 2 and the following table.
AC Line Voltage Clearance Distance (d) (d’)
120 V
≥
3.2mm (0.126 inches)
Table 2: Leakage current ratings for selected areas
Note: This table is unofficial and for reference only. Be sure to confirm the precise values.
AC Line Voltage Load Z Leakage Current (i) Earth Ground (B) to:
120 V
0.15
µ
F CAP. & 1.5k
Ω
RES.
Connected in parallel
i
≤
0.5mA Peak Exposed accessible parts
Fig. 1
Fig. 2