Realistic HTX-100 - Microprocessor Section Troubleshooting; PCB Views and Parts Lists; PCB (Top and Bottom) VIEWS

MICROPROCESSOR SECTION
No good.
Check if the
LCD displays
normally.
NG
_____.
Check if the clock
is 2MHz
at pins
44 and 45 of
IC401.
OK
NG
_____.
Check if the
waveform is
as
following figure
at pin43 of
NG
IC402, when
f-+-
power switch
is on.
I
I
JLE
I
I
on_..l
~1mS
OK
Check waveform at ~ Replace
pins 1 and 52
of IC40 1. defactive R404.
OK
Check waveform of I N~
Replace
defective
IC402.
pins 6 ....... 13 of IC401. (
~----------~------- ~------------~
OK
Replace defective LCD.
Check if S613
operates
NG
NG
normally.
_......
Check voltage of
IC403.
_____.
• OK
OK
Replace
defective S613.
NG .
Check
if S605 ....... S612 Replace defective
operate normally.
~
Switch (e).
OK
Check
if PTT
operates
NG
Check voltage at
pin41
NG
normally.
~
of IC402.
~
~OK
OK
NG
Check
voltage
of
0401.
~
Check the
NG
Replace
output of Mute
and the output
_____.
defective
of BEEP.
IC402.
OK
Microprocessor section is not defective.
-19-
Check NG Replace
voltage
~ defective
of IC404. parts.
Check
voltage
NG Replace
qf
0402
• ~ defective
0403. parts.
Replace
defective Y
40 1.
Replace defective IC403.
Replace defective S603
and/ or Mic. Jack.
Check voltage
at pin56 of
IC402.
t NG
Replace
defective
IC402.