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IV
Section
Figure 4-1
Exc es s iv e heat or pressure can lift th e copper s trip from the boa rd . Av oid da mage by us ing a low power
soldering iron (5 0 watts ma ximum) and following these instruc tions. Copper that lifts off the board should
be cemented in place w ith a quick drying ac etate base cement having good electrical insula ting properties.
A break in the copper should be repaired by soldering a short length of tinned copper w ire across th e break.
Use onl y high qua lity rosin core solder when repa iring etched circuit boa rds .
After soldering. clea n off any excess flu x and coat [he repaired a rea with a high quality electrica l varnish
or lacquer.
When replacing components with multiple mounting pins such as tu be s ockets, electrolytic capacitors , a nd
potentiometers, it will be neces sa ry to lift eac h pin slightl y, working a round the components severa l times
u ntil it is free.
If
the specific instructions ou tlined in the steps bel ow regarding etched circuit boards w ithout
WARNING:
eyelets are not followed, e xtensive damage to the etched c ircuit boa rd will result.
1 .
Apply heat sparingly to lead of component to be
replaced.
If lead of component passes through
an eyelet in the circuit boa rd. appl y h ea t on com
ponent side of board . If lead of component does
not pass through an eyelet. a pply heat to con
dUc tor side of board .
3. Bend clea n tinned leads on new part a nd care
fu lly insert through eyelets o r holes in boa rd .
In the ev ent that either the circu it board ha s been damaged or th e convenrional method is impractic al, use
method shown below. This is especially applicable for circ uit boards without eyelets.
I.
Clip lead a s shown below.
Th is procedure is u s ed in the field only as an a lterna te mea ns of repair. It is not used within the fac tory.
4-0
SERVICI N G ET CHED CIRCUIT BOARD S
Figure 4-1.
Se rvicing Etched Circuit Boards
NEVER USE
2. Reheat solder in vacant eyelet a nd quickly in
sert a small awl to cl ean inside of hole. If hole
does not have an eyelet. insert awl or a #57
dri ll from conductor side of boa rd.
4. Hold pa rt against board (avoid overhea ting) a nd
solder lea ds. Appl y heat to compon ent lea ds on
correct s ide of boa rd as expla ined in step 1.
2. Bend protruding leads upward.
new component a round protruding lead . App ly
solder using a pair of long nose pliers a s a
heat s ink.
s � � �
� �
Model 456A
FLU X .
PASTE
Bend lead of
00395-1
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