Specifications
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If the problem
is
not found
and
corrected with the procedures on the previous
page,
then follow this Symptom/Remedy
Guide:
SYMPTOM SUSPECT
REMEDY
Snow on
TV
(with
or
Unit
is
not turning on. Review voltage check in
Trouble·
without diagnostic test
shooting Guide.
pattern visible.)
Fuse
is
blown.
Check
continuity
of
fuse on Logic
•
,
Board. Replace if
open.
If new fuse
blows quickly, check for
proper
voltages from Power
Supply
Board.
I f voltages 0
K,
check for
shorted
components
or
traces on Logic Board.
Voltage
at
pin 2
of
RF
Modulator
is
Check
R7
and
CIS.
not
about
+6 VDC.
RF
Modulator
is
defective. Connect a known-good
Modulator
in
paraliel with
the
Modulator.
Connect
the
RF
Cable
to
the
known-good
Modulator
and
touch
the
cases together.
If
this clears the problem, replace
Modulator.
Solder bridges
or
foreign material
Inspect
for
solder bridges
or
foreign
are
causing shorts. material on the Logic Board.
The +12 VDC supply i. defective.
Troubleshoot
the
+12 VDC supply and
distribution on the Logic Board.
Grey·white screen with NO Clock circuitry
not
functioning. Review procedure in Troubleshooting
flash observed on
the
TV Guide on
troubleshooting
clock
screen when the reset switch circuitry.
is
depressed.
5.7 VDC
to
STIC missing. Measure 5.7 VDC
at
pin
20
of
STIC
(U4).
If
not,
troubleshoot
5.7
VDC
distribution
system
on
Logic
Board.
-2.25
VDC
to
STIC miosing. Measure
-2.5
VDC
at
pin
40
of
STIC
(U41. If
not,
troubleshoot
-2.25
VDC
distribution
system
on
Logic Board.
Solder
bridges
or foreign material
Remove
any
foreign material or
solder
causing
shorts
on
Logic Board. bridges.
Grey-white screen WITH
The
test
cartridge
is
incorrectly or Insert cartridge correctly.
flash
occurring
on
the
TV
incompletely inserted
into
the
screen
when
reset
switch
Master
Component.
is
depressed.
Master
Component cartridge socket
Visually inspect socket for bent
pins,
is
defective.
foreign
material, etc.
DefectivI Test Cartridge. Try
another
cartridge.
Clock
Signal
path
not
complete.
Review
procedure
in
Troubleshooting
Guide on
checking
clock circuitry.
+5 VDC supply problems.
Troubleshoot
+5 VDC
supply
and
distribution path.
-
Defective
IC.
Insert test cartridge
and
run
Diagnostic
Test Routine. Replace
any
ICs
that
are
indicated as failed.
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