Heathkit H9 Manual page 36

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General Troubleshooting Information
NOTE: The following checks will be most effective if
you apply them to one part of the kit at a time.
1,. Recheck the wiring. Trace each lead in colored
pencil on the Pictorial as it is checked. It is
frequently helpful to have a friend check your
work. Someone who is not familiar with the unit
may notice something you have consistently
overlooked.
2. About 90% of the kits that are returned for repair
do not function properly due to poor connec-
tions and soldering. Therefore, many troubles
can be eliminated by a careful inspection of
connections to make sure they are soldered as
described in the "Soldering" information at the
beginning of the Assembly manual. Reheat any
doubtful connections. Be sure all wires are sol-
dered at places where several wires are con-
nected.
3. Check each circuit board foil to be sure there are
no solder bridges between adjacent connec-
tions. Remove any solder bridges by holding a
clean soldering iron tip between the two points
that are bridged until the excess solder flows
down onto the tip of the soldering iron.
Check each resistor value carefully. A resistor
that is discolored, or cracked, or shows any sign
of bulging would indicate that it is faulty and
should be replaced.
4 .
5.
6.
7.
Be sure each diode is installed with the banded
end positioned correctly.
Check all component leads connected to the cir-
cuit boards. Make sure the leads do not extend
through the circuit board and come in contact
with other connections or parts.
The components listed in the "Possible Cause"
column of the "Troubleshooting Chart" are the
most likely causes (but not necessarily the only
causes) of a problem. When you check these
components, look first for the following items:
Parts installed incorrectly or backwards.
This pertains especially to diodes, elec-
trolytic and tantalum capacitors, and trans-
istors.
Unsoldered or inadequately soldered parts.
Reheat the connections in the area of a
problem.
Incorrect or interchanged parts. Check the
part numbers on the diodes and transistors.
NOTE: In an extreme case where you are unable to
resolve a difficulty, refer to the "Customer Service"
information inside the rear cover of the Manual. Your
"Warranty" is located inside the front cover.