25
e. Hold the head of the LDR from the outside of the heat-shrink. It is important that the LDR and
LED are in direct contact with each other. Carefully heat this end of the tube until it closes
around the LDR leads (60,61). While it is still very hot, use your pliers to pinch the end
closed around the LDR leads (62a,b).
60
61
62a
62b
f. MARK THIS OPTOCOUPLER CONTAINING THE MARKED LDR with a scrap of tape or a dot
of ink (63).
63
g. Repeat this process to make the second optocoupler. If you are making the Stereo upgrade,
please do not make the second pair of optocouplers at this time. Leave the second pair of
LDRs sealed in their bag so you cannot mix up the pairs of optocouplers. Do not make the
second pair until the first pair is safely installed on the main PCB.