Receiver - Midland Syn-Tech 70-342XL Service Manual

RECEIVER TROUBLESHOOTING CHART
7 0 - 3 4 2 ~ ~ / 4 4 2 ~ ~
Fold Out
-1C401 d e f e c t i v e o r s h o r t
on RX +8VDC l i n e
1.7V
Bad Check CM202 NO
Dead
.
OV
_OK
Check Main
VCO Receiver
Problem
A .
p i n 1 f o r
-
TP701 v o l t a g e
-
( 1 . 5 - S V ) S l g n a l
- R X
ov
0 K
(OV o r 6.5V)
Check IC401 p i n 6
+8VDC
8V 0.7V
N o
Check. IC401
P i n 5
\'
Check 4203 and a l i g n m e n t
A
of L209 and L210
A
\I
Weak S i g n a l
C h e c k I C 2 5 1 , X 2 5 1 a n d
'
S q u e l c h
Distorted S l g n a l
I
Check IC252 A u d i o
1
Re Cer t o CPU/PLL
R e p l a c e
11
a l i g n m e n t o f L252 -Output
IC
. T r o u b l e s h o o t i n g
C h a r t
4 4 0 3
Check TP752 f o r R e c e i v e r
OK
0 K
T r a c k i n g C o n t r o l V o l t a g e 95 E r r o r Code
and A d j u s t RV752.
C
(OV-9V)
Check Q201,Q202,Q251,FL251,
Check S q u e l c h IC251 p i n s 1 0 , 1 1 ,
1 2 , 1 3 & 1 4 . Q252,D252 and D253
-
-
O K
Check 4259,9260,
-
-
Q261,D259, dnd D260
-
FL252,FL253 and a l i g n m e n t
of L201,L202,L203,L204,
L205,L206,L208 and L251.