Technics SX-PR270 M Service Manual page 13

can be verified by
TEST MODE
Procedure
1 | MAIN
RAM (IC6, 8, 9), ROM (IC4, 5)
check
| |
1 2 3 4 1 2 3 4
1.
RAM OK, ROM OK
———__—>
e
af e
e e
e e 6.3
! 1 1
| { 1
2. RAM OK, ROM (IC4) defective
——_—_——-+
© e
e @ -
e e.6.°8
! I 1 i
i i |
3. RAM (IC6) defective, ROM OK
—_ @©
@ ® eee
@®e
t et t ft
Icé6 1c8 IC9 IC4 IC5
Note: @ indicates short flash time= OK
== indicates long flash time = Defective
V25 gate array (IC2) check
While pressing two C keys simultaneously, turn on the power switch.
3 | CPL
cPSQ
CPR
UIT IEA ded ddd
t_1 :
D keys
1 4 1 2 3 4
1. OK
———_—_>
°
e eos
@
1
I
+-@---@
2
e
(
1
i
@
|
|
i
|
CPR P.C.B. Gate Array (IC1|
t
CPSQ P.C.B. Gate Array (IC1)
!
{
|
|
|
t
CPL P.C.B. Gate Array (IC 1)