Sony dvpns 777 p service manual

Page 2

SAFETY CHECK-OUT

After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:

Check the area of your repair for unsoldered or poorlysolA
dered connections. Check the entire board surface for solder
splashes and bridges.

Check the interboard wiring to ensure that no wires are
pinched or contact high-wattage resistors.

Look for unauthorized replacement parts, particularly transisA
tors, that were installed during a previous repair. Point them
out to the customer and recommend their replacement.

CAUTION:
The use of optical instrument with this product will increase eye
hazard.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.

WARNINGII

WHEN SERVICING, DO NOT APPROACH THE LASER
EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS
NECESSARY TO CONFIRM LASER BEAM EMISSION,
BE SURE TO OBSERVE FROM A DISTANCE OF
MORE THAN 25 cm FROM THE SURFACE OF THE
OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.

SAFETY-RELATED COMPONENT WARNINGI!

COMPONENTS IDENTIFIED BY MARK A OR DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL T0 SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.

4. Look for parts which, though functioning, show obvious signs
of deterioration. Point them out to the customer and recomA
mend their replacement.

5. Check the B+ voltage to see it is at the values specified.

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.)

ir : 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 solderjoint 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.