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IV - TROUBLESHOOTING AND REPAIR
-
This
section is devoted exclusively to the trouble
shooting. repair and adaptation of Electronic
Shutter Modules. Consequently, mechanical
troubleshooting and repair infonnation
will
not
be
presented. For in depth treatment of mechani·
-
cal aspects of Shutter operation, including trouble
investipting, see the Manual on Automatic Shutter
operation published. in May 1968.
A.
TESTING
1.
Resistors and Capacitors
-
Looking at the top of the module. the various
components are easily identified by shapes andl
or color markings. Resistors are long. tubular de
vices..
with
four
(4)
colored stripes around the
body: capacitors are of two types: one is similar
to the resistor shape, but has only 2 colors or less
-
stripes. and may have one end rounded: the other
is a flat. disc"'5haped type. usually mounted
vertically.
3.
Testing Resistors
Because resistors may
be,
and usuaUy are, electri
cally in parallel. it is necessary to unsolder one lead
from the module in order to test it (Fig. 4-1).
-
- -
CAPACITOR
41
Place [he test leads of an ohmmeter. set at the
proper scale, on each end of the resistor. The
meter should register the approximate resistance
of the component being measured. If the meter
needle fails to move, the resistor is no good and
must be replaced. Similarly. if the needle registers
zero and remains there. the resistor may be short
ed. To decide positively.
chan~
the meter scales.
zeroing the needle for each range and retest. If
the result is still a meter reading of zero. replace
the resistor in question.
b. Testing Capacitors
Capacitors may be checked in a similar manner.
Unsolder either lead from the module. place the
probes of an ohmmeter. set at any scale, on each
lead of the capacitor. The meter needle will de-
flect slightly and then. slowly. start to drop back;
this shows that the capacitor has been charged.
Reverse the probes on the capacitor leads. Now.
the meter needle must deflect fully, and then drop
back; this indicates capacitor discharge. The pre
vious sequence is nonnal and usuaUy shows a good
component. If the needle deflects and remains
on zero, the capacitor is shorted and must be re-
placed. If the needle does not move at aU, the
capacitor is open, and also, must be replaced.
2. Replacing Resistors and Capacitors
To replace any component soldered into the module.
the solder must be removed with a vacuum type
soldering iron - a so-called solder gobbler: this is
necessary to avoid damaging the flexible circuit.
When replacing a part, trim and bend the new leads
to match those of the
part
removed and insert the
leads into the same tenninal hole from which the
old component was removed. Solder the new
component in place.
3. Testing Transistors
Transistors are of several types, color coded as
previously explained in the Electrical Values
tables - generally identifiable by the three (3)
lead configuration - Emitter-Base-Collect.or
(E-B-C). The PhotoceU is unique and. therefore.
identification is no problem, as in the Integrated
Grcuit (I.e.).
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