3
SAFETY CHECK-OUT
After correcting the original service problem, perform the
following safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, “metallized” knobs, screws,
and all other exposed metal parts for AC leakage. Check leakage as
described below.
LEAKAGE
The AC leakage from any exposed metal part to earth ground
and from all exposed metal parts to any exposed metal part having
a return to chassis, must not exceed 0.5 mA (500 microamperes).
Leakage current can be measured by any one of three methods.
1.
A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’ instructions to use these
instruments.
2.
A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3.
Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The “limit” indication
is 0.75 V, so analog meters must have an accurate low-voltage
scale. The Simpson 250 and Sanwa SH-63Trd are examples of
a passive VOM that is suitable. Nearly all battery operated
digital multimeters that have a 2V AC range are suitable. (See
Fig. A)
To Exposed Metal
Parts on Set
0.15
µ
F
1.5 k
Ω
AC
Voltmeter
(0.75 V)
Earth Ground
Fig. A. Using an AC voltmeter to check AC leakage.
CFD-G55
SECTION 1
SERVICING NOTES
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electrostatic
breakdown because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic breakdown and also use
the procedure in the printed matter which is included in the repair
parts.
The flexible board is easily damaged and should be handled with
care.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick-
up block. Therefore, when checking the laser diode emission,
observe more than 30 cm away from the objective lens.
CHUCK PLATE JIG ON REPAIRING
On repairing CD section, playing a disc without the CD lid, use
Chuck Plate Jig.
• Code number of Chuck Plate Jig : X-4918-255-1
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
1.
Press CD open knob.
2.
Open the lid for CD.
3.
Push on SWITCH (S801) as following figure.
4.
Confirm the laser diode emission while observing the objecting
lens. When there is no emission, Auto Power Control circuit or
Optical Pick-up is broken.
Objective lens moves up and down once for the focus search.
Insert a precision
screw driver and push
SWITCH (S801)
Summary of Contents for CFD-G55 - Cd Radio Cassette-corder
Page 26: ...26 26 CFD G55 5 10 Schematic Diagram MAIN Section 1 2 See page 34 for IC Block Diagrams ...
Page 29: ...29 29 CFD G55 5 13 Schematic Diagram AMP Section ...
Page 31: ...31 31 CFD G55 5 15 Schematic Diagram CONTROL Section ...
Page 33: ...33 33 CFD G55 5 17 Schematic Diagram POWER Section ...
Page 53: ...53 CFD G55 MEMO ...
