RCA SelectaVision VideoDisc SFT 100 Service Data page 64

CED-1 Addendum-2
SERVICING PRECAUTIONS
(Continued)
Integrated Circuit Replacement
RCA VideoDisc Play Circuit Boards use slotted IC mounting holes
(in some applications). The 1С leads are bent flat against the
board to provide a good mechanical contact to the circuit-board
connecting pads. To achieve best replacement results, the follow-
ing procedure should be used:
1. Using a Weller WP 25 with an ST-5 tip or similar soldering
iron, desolder and straighten IC pin leads in one operation.
Because of the shape of the ST-5 tip, it can be used to pry the
lead upright while melting the solder as shown.
Use Soldering Iron Tip To Pry Leads
2. Use a solder sucker or wicking technique to remove any ex-
cess solder from the circuit-board pads before removing the
Ic.
LOW WATTAGE
SOLDERING
IC Removal
3. Insert new ІС. Bend pin leads over against the appropriate
copper pads and carefully solder each lead. Observe ІС һап-
dling procedures outlined on preceeding page.
Clean Area With Brush
4. After replacing an IC, clean the surrounding board area
with a small wire brush, e.g. GC Electronics #9494. This
will remove small solder droplets which are held in the
melted acrylic coating (when coating is utilized). It is not
necessary to reapply acrylic coating after servicing.
Circuit Board Repair
Excessive heat applied to the copper pattern of any circuit board
will cause the pattern to lose adhesive bonding to the board.
When this happens, the copper becomes separated or "lifted".
There are many commercially available methods for repairing
such defects. In the event printed circuit damage is evident (cop-
per pattern broken, lifted, etc.) the following procedures are
recommended for circuit board repair.
NOTE: The PW AC IN circuit board should only be repaired by
the method "defective" copper at other connections"
see Page 1-19.
DEFECTIVE (8
COPPER
PATTERN
зв
Defective Copper Pattern
Defective Copper at an IC Connection
To repair defective copper at ап IC connection pad, the following
Procedure for installing a copper-side jumper wire should be
used. Use this method only at IC connections.
1, Using a sharp knife, carefully remove the damaged copper.
(Remove no more than necessary.)
REMOVED
- H
6
Remove Defective Copper
2. Carefully scratch the solder resist and acrylic coating (when
coating is utilized) from the end of the cut conductor.
3. Using small-gauge bare hook-up wire, make a crimp and
solder connection to the appropriate IC lead. Route the lead
along the same path as the original copper conductor, solder
the lead to the scraped area of the copper pattern, and clip off
excess lead.
an ЈАК) | |"
2
К ШАЙЫ SARE JUMPER
" * WIRE
CRIMP AND
SOLDER
install Jumper Wire and Solder