Tait T858 User Manual

M850-00 T855 Fault Finding B5.11
Copyright TEL 31/09/98
5.7.1.3 CTCSS Decode
Y
No square wave or
uneven mark/space ratio
Use PGM800Win to
select a channel
with a CTCSS tone
pro
g
rammed.
Check serial communications.
(See separate flow chart).
Cannot select a channel
Check IC810 pins 24 & 26
(microcontroller).
Are there 5V square waves at
the CTCSS frequency?
Y
Check IC850 pins 1 & 14.
Are there 9V square waves at
the CTCSS frequency?
Replace IC850.
Y
Is IC850 pin 7 low and
Q845 collector hi
g
h?
Replace IC850
or Q845.
N
Y
Is IC810 pin 31 low? Replace IC810.
N
Y
Check the receiver
mute circuit.
Set test equipment to correct
channel/CTCSS tone.
Check IC830 pin 7.
Is there a square wave at
the CTCSS input frequency?
Replace IC810.
No square waves or
uneven mark/space ratio
No square waves or
uneven mark/space ratio
Check the input filter
is operatin
g
correctly
(IC830 pin 8).

Tait T858 Specifications

General

Brand	Tait
Model	T858
Category	Accessories
Language	English