IPC 7711A - 第245页
CAUTION Some components may be sensitive to high temperature. 17. Cure the epoxy per the manufacturers instructions. 18. After the epoxy has cured clean the area. EVALUATION 1. Visual examination for alignment and overla…
7. Select a wire to match the width and thickness of the conductor to be replaced.
Cut a length approximately as needed. See Table 1 for Solid Wire Equivalents.
8. Strip the wire and tin the ends if needed. Non-insulated wire may be used for
short repairs if conductors are not crossed.
9. Clean the wire.
10. If the wire is long or has bends, one end may be soldered prior to forming the
new shape. Place the wire in position. The wire should overlap the existing con-
ductor a minimum of 2 times the conductor width. The wire may be held in
place with Polyimide tape during soldering.
NOTE
If the configuration permits, the overlap solder joint connection should be a
minimum of 3.00 mm from the related termination. This gap will minimize the
possibility of simultaneous reflow during soldering operations. Refer to 7.1 Sol-
dering Basics.
11. Apply a small amount of liquid flux to the overlap joint.
12. Lap solder the wire to one end of the conductor on the printed wiring board
surface. Make sure the wire is properly aligned. (See Figure 2.)
13. Bend the wire as needed to match the shape of the missing conductor. (See
Figure 3.)
NOTE
Wire guide tools can be used to form the wire as needed.
14. Lap solder the other wire end to the remaining conductor on the printed wiring
board surface using solder and a soldering iron. Make sure the wire is properly
aligned. (See Figure 4.)
15. Remove any Polyimide tape and clean the area.
NOTE
It may be necessary to encapsulate the solder joint connection if electrical spac-
ing is reduced or the connection is beneath a component.
16. If desired bond the wire to the printed wiring board surface with adhesive, epoxy
or tape dots. (See Figure 5.)
Figure 5 Bond the wire to the surface
with adhesive or tape.
Table 1 Solid Wire Equivalents
Conductor Width
2 oz. Copper
Equivalent Solid
Wire Diameter
0.25 mm #34, 0.15 mm
0.38 mm #32, 0.20 mm
0.50 mm #31, 0.23 mm
0.78 mm #29, 0.28 mm
2.08 mm #26, 0.46 mm
3.18 mm #23, 0.58 mm
When using solid wire to repair a conductor, there should be no reduction in the
cross sectional area.
IPC-7721A
Number: 4.2.4
Revision:
Date: 2/98
Subject: Conductor Repair, Surface Wire Method
Page2of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---
CAUTION
Some components may be sensitive to high temperature.
17. Cure the epoxy per the manufacturers instructions.
18. After the epoxy has cured clean the area.
EVALUATION
1. Visual examination for alignment and overlap of wire.
2. Electrical tests as applicable.
IPC-7721A
Number: 4.2.4
Revision:
Date: 2/98
Subject: Conductor Repair, Surface Wire Method
Page3of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---
NOTES
IPC-7721A
Number: 4.2.4
Revision:
Date: 2/98
Subject: Conductor Repair, Surface Wire Method
Page4of4
Copyright Association Connecting Electronics Industries
Provided by IHS under license with IPC
Not for Resale
No reproduction or networking permitted without license from IHS
--``,``,-`-`,,`,,`,`,,`---