Heathkit IO-4550 - Page 39

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Ge gumarrxire
The following symbols and procedures are used in the
troubleshooting charts: The numbered Test Charts are in the
“Illustration Booklet.”
—
[>
R
Follow the ‘““YES” arrow when you obtain the
Proper measurement or condition.
Follow the ‘‘NO” arrow when you do not obtain
the proper measurement or condition.
This symbol, “APPROXIMATELY EQUAL
TO,” before a voltage measurement indicates
that this voltage may vary as much as +20%.
Page 37
REPEAT]
This
means
to
repeat
a
particular
test
after
a
TEST
#
|
problem
has
been
located
and
corrected.
All voltages given in the troubleshooting charts were taken
with a nominal line voltage of 120 VAC.
Components are listed in the order in which failure or a
problem is most likely to occur.
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.
GENERAL TROUBLESHOOTING
Oscilloscope does not
turn on.
Power lamp lights, no
trace.
Trace is visible, but
one channel will not
center, or is not
visible.
Gain factor wrong.
Gain Factor does not
change in proper order.
Bandwidth too low, or
rise time excessive.
Can not balance a vertical
amplifier.
Line cord not plugged in.
Fuse F1.
Switch SW3, SW4, or SW5.
Proceed to “Locating the
Problem” on Page 40.
Perform DC Balance
adjustment.
Go to Test Chart #6.
Go to Test Chart #11.
Check high voltage
(—1700 VDC).
Calibrate Oscilloscope.
Calibrate the Oscilloscope.
Check input attenuator
RC networks.
Check switched-gain
amplifier RC networks.
Adjust wire separation to
vertical deflection plates
in CRT.
Adjust high frequency
compensation C118 — (1 or 2).
Interchange transistors Q101
and Q102 of that channel.