SERVICE MANUAL FOR INFANT INCUBATOR EDITION/REVISION B/0
From sheet 1
Output terminal of solid no Replace solid relay
relay and relay K1 can or relay K1
work?
yes
no
Voltage of U1-2 is
Check inductor T1
> 5mV
yes
no
Voltage of U1-1
Check U1,R1 ,C4
is >2V?
yes
no
Base of triode Q1
Check R2,R6,C5
>0.7V?
yes
no
Base of triode Q1
Repalce triode Q1
>0V?
yes
Connet pin 1 (ssr-ctr) and pin3 (relay-ctr) on J8 to GND
make two control signals high level
To sheet 3
FLOW CHART 5.11 HEAT SYSTEM FAILURE (SHEET 2 OF 4)
I2 5-19
SERVICE MANUAL FOR INFANT INCUBATOR EDITION/REVISION B/0
From sheet 2
yes
Base of triode Q1,Q3 Check triode Q2,Q3
is 0V? and resistor R8, R9
no
Is there +12V on yes
Replace triode
control terminal of solid
Q2 or Q3
relay and relay K1
no
no
Voltage U1-2 is
Check inductor T1
0V?
Yes
no
Voltage U1-1 is
Check U1,R1,C4
0V?
Yes
no
Base of triode Q1
Check R2, R6, C5
is 0V?
yes
no
Base of triode Q1
Replace triode Q1
is 5V?
yes
To sheet 4
FLOW CHART 5.11 HEAT SYSTEM FAILURE (SHEET 3 OF 4)
5-20
I2
SERVICE MANUAL FOR INFANT INCUBATOR EDITION/REVISION B/0
From sheet 3
Connect power board and main board
Switch off during measuring
The pins on porer no
board J8-1, 3, 4 and Replace connecting wire
J2-1, 3, 4 on main
board works?
yes Element number from here is on
mainboard
Connect pins U8-2, 11 to VCC power
no
Pin of U8-9, 18 is
Check U8
5V?
Yes
Measure the voltage of U15-2 for self-checking
yes
no
Voltage is changing
from low level to high Replace U15
level?
yes yes
Still alarming after
Replace main board replacing U15
FLOW CHART 5.11 HEAT SYSTEM FAILURE (SHEET 4 OF 4)
I2 5-21
SERVICE MANUAL FOR INFANT INCUBATOR EDITION/REVISION B/0
Power Failure Alarm
Is there AC power on No
Check outside power input
input socket?
Yse
No Check the connecting wire of
Initial trans for mer is
trans for mer and ower cord,
AC power?
and Fuse F1, F2, F3 on AC
entry board
Yes
No
Secondary output of
transformer is 9V, 15V? Replace transformer
Yes
On power board Pin 3 on U2, U3 is +5V? Check U2, U3 and prefix circuit
Yes
Pin4 of U4 is No
On power board Check U4 and prefix circuit
+12V?
Yes
Cross point of R17, No
On power board R18 is +2.5V? Check R17, R18
Yes
To sheet 2
FLOW CHART 5.12 POWER FAILURE ALARM (SHEET 1 OF 2)
5-22
I2
SERVICE MANUAL FOR INFANT INCUBATOR EDITION/REVISION B/0
From sheet 1
Crosspoint of No
On power board R19, R20 is 2.5V? Replace R19, R20
Yes
Crosspoint of No
On power board R21, R22 is Replace R21, R22
2.1V?
Yes
No
Pins7, 1 of U6
On power board Replace U6
is high level?
Yes
No
Pin5 of U8 is low
On main board Check the connection of power board
level?
and main board
Yes
No
Pin4 of U8 is
On main board Replace U8
low level?
Yes
Replace main board
FLOW CHART 5.12 POWER FAILURE ALARM (SHEET 2 OF 2)
I2 5-23
