Troubleshooting 3 - Investigate the Functional Group
Now you go step by step through all functional groups.
Here you take a close look at the circuit and components,
the power supply and you measure the signals at the input and output.
Are all components connected
as shown in the circuit diagram?
Check solder joints for "cold" joints
or short circuits.
Are components visibly damaged?
Is the polarity correct?
For batteries check the charge level,
for Power Supply Units check the set voltage.
Are all integrated circuits connected to the power supply?
Signals at the Input and Output
In an additional step you examine whether the
signals at the input and output of function group
function as expected.
Thereby it may be useful...
to remove wires temporarily,
to use test signals and
to remove individual components.
You repeat these steps for each functional group
until you have narrowed down the group
which containing the error.
Once you have found the faulty functional group,
you search for the error within the group...