Tait T858 - Regulator

B5.12 T855 Fault Finding M850-00
31/09/98 Copyright TEL
5.7.2 Regulator
Check for
overheatin
g
components &
short circuits.
13.8V present on
IC630 pin 3?
5.3V present on
IC630 pin 1?
Check Q620,
Q630 & IC640.
Check Q660 is
switchin
g
at
approx. 180kHz.
5V present on
IC610 pin 2?
Replace IC630.
Check R615.
Replace IC610.
Check continuity
from D-ran
g
e
connector pin 9.
(D-ran
g
e 1)
N
Y
N
Y
N
Y
N
Y
N
Re
g
ulators OK.
Y
20V present
on TP603?
9.0V present
on TP602?