Sony STR-K7100 Service Manual - Page 3

Model Identification, Unleaded Solder, Lead Free Mark - instructions

Page 3 highlights

STR-K7100 SAFETY CHECK-OUT (US MODEL) After correcting the original service problem, perform the following safety check 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 TEST 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 microampers.). 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 lowvoltage 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 2 V AC range are suitable. (See Fig. A) To Exposed Metal Parts on Set 0.15 µF 1.5 kΩ AC voltmeter (0.75 V) Earth Ground Fig. A. Using an AC voltmeter to check AC leakage. MODEL IDENTIFICATION - BACK PANEL - MODEL US Part No. PART No. 2-897-800-6s Notes on Chip Component Replacement • Never reuse a disconnected chip component. • Notice that the minus side of a tantalum capacitor may be damaged by heat. • UNLEADED SOLDER Boards requiring use of unleaded solder are printed with the leadfree mark (LF) indicating the solder contains no lead. (Caution: Some printed circuit boards may not come printed with the lead free mark due to their particular size.) : LEAD FREE MARK Unleaded solder has the following characteristics. • Unleaded solder melts at a temperature about 40°C higher than ordinary solder. Ordinary soldering irons can be used but the iron tip has to be applied to the solder joint for a slightly longer time. Soldering irons using a temperature regulator should be set to about 350°C. Caution: The printed pattern (copper foil) may peel away if the heated tip is applied for too long, so be careful! • Strong viscosity Unleaded solder is more viscous (sticky, less prone to flow) than ordinary solder so use caution not to let solder bridges occur such as on IC pins, etc. • Usable with ordinary solder It is best to use only unleaded solder but unleaded solder may also be added to ordinary solder. 3

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3
STR-K7100
MODEL IDENTIFICATION
— BACK PANEL —
Part No.
MODEL
PART No.
US
2-897-800-6
s
1.5 k
0.15
μ
F
AC
voltmeter
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
SAFETY
CHECK-OUT (US MODEL)
After correcting the original service problem, perform the follow-
ing safety check 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
TEST
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 microampers.).
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” indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are suit-
able.
(See Fig. A)
Fig. A.
Using an AC voltmeter to check AC leakage.
UNLEADED SOLDER
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
Unleaded solder melts at a temperature about 40
°
C higher than
ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350
°
C.
Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
Strong viscosity
Unleaded solder is more viscous (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.
Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
Notes on Chip Component Replacement
Never reuse a disconnected chip component.
Notice that the minus side of a tantalum capacitor may be damaged
by heat.