Table of Contents
Advertisement
MAINTENANCE
WJ-8718-19/FE HF RECEIVER
1.
Deenergize the receiver.
Select any detection mode.
2.
Remove the front panel and gently pull it out several
inches from the receiver main chassis, being careful not
to place any strain on the interconnecting cables.
3.
Access and execute the BITE program as described in
Section II.
4.
If a single switch does not respond to BITE, check the
switch for continuity and replace if bad.
5.
If all switches and displays appear defective, check the
clock inputs to pin 3 of Ul and U2 of the Front Panel
Encode board.
Replace U13 if not present.
6.
If all group 1 switches and LEDs are defective, replace
Ul and any associated chips.
If all group 2 switches
and LEDs are defective, replace U2 and any associated
chips.
7.
If the problem is associated with a particular row or
column,
replace
chips associated with the row or
column.
8.
If all LEDs in Group 1 are defective, replace U3 on the
Encode Board.
If all LED's in Group 2 are defective,
replace U7 on the Encode Board.
9.
Check the RD, WR and RESET inputs to Ul and U2.
If
defective, replace U19, U18 and U15.
10.
If the tuning wheel does not increment the display,
replace U17 and U21.
11.
When the Encoder/Switch Board has been repaired and
is operating satisfactorily, deenergize the receiver and
remove all test equipment, unless further testing is
desired.
4-3.4.31
Front Panel Audio Circuits, (p/o 796013) Testing and Troubleshooting
Front Panel Interconnect Testing and Troubleshooting includes a checkout
procedure and fault isolation information.
An Oscilloscope (Table 4-1) and Signal
Generator are required to perform the tests outlined below.
Tne testing and troubleshooting information in this paragraph is keyed to
the following testing procedure used to isolate the module fault to a defective
integrated circuit or functional group of integrated circuits. Perform the following
JTOCedure in thp spniipnr>p triuon
4-56
Advertisement
Chapters
Table of Contents
