Pickup Head Initial Position - JVC TH-A25 Service Manual

5.2.3 PickUp Head Initial Position

PickUp Head Initial Position
(1) 1. Move Pick Up Head to inner direction until pin5 of MJ4="L"
(2) 2. If pin5 of MJ4="L", then move Pick Up Head to outer direction for a short time.
(3) 3. Turn On the Laser of Pick Up Head to judge that disc is present or not.
Does Pick Up
Move to inner
Does Pick Up
direction again?
Does Laser Turn
OK
Check voltage at
pin8 of RCN1 is
Check BUS line between RIC1 and
SIC1,SIC1 and MIC1
1-20 (No.MB141)
3
N
direction?
Y
N
Move to out
Y
On?
N
Y
about 2.5V?
N
Is pulse of 2.5
+-2.5V developed
at pin3,4 of MJ4?
N
Is pulse of 2.5
+-2.5V developed
at pin13 of SIC1
Is pin5 of MJ4 =
"L" appeared?
Y
Check line between SIC1
and MJ4
Replace Pick Up Head
Check
Y
connection
between PCB
and MECHA
Check
peripheral
Y
circuit of SIC1
and DRIC1
Check BUS
N
line between
SIC1 and MIC1
N Check
connection
between PCB
and MECHA