CAS Scale EC-II Service Manual

Service Manual for EC-II counting scale

Ⅰ. Phenomena of trouble

1) Trouble of part

The trouble phenomena are as following:

a) Buzzer-----buzzer doesn’t make sound, or sometimes make sound and sometimes doesn’t make sound.
b) LCD-----The display is faultily.
c) Backlight-----The backlight doesn’t lighten, or sometimes it lighten and sometimes doesn’t lighten:
d) Key -----The key don’t work.

2) Trouble of load cell

The trouble phenomena are as following:

a) The display data is drifting.
b) The display data doesn’t change, or the internal resolution value is not in the natural range.
c) The internal resolution data drift badly.
d) The initial resolution is drifting.

3) Trouble of power supply

The phenomenon is as following:
The scale doesn’t work or the “low voltage” symbol comes out after turning on.

4) Trouble of the PCB

The phenomena are as following:

a) Trouble of display board-----the display is abnormal, or shows nothing.
b) Trouble of main board

 There is nothing in the display when turn on the scale.
 The scale can not be powered on.
 The weighing is unstable.
 The internal resolution is out of the normal range.

c) Trouble of RS-232 board-----The scale doesn’t transmit any data.

Ⅱ. To solve the trouble

1．The scale can not be powered on

Y N

N Y

Y

Y
N

N

N

Y

N

Scale can not

be p

owered on.

Connect the scale
with AC

p

ower.

Check if the AC
li

g

ht is on.

The output voltage
of L7808 is 8V.

L7808 is damaged,
re

p

lace it.

Check the output
voltage of adapter
is about 17V.

The AC jack (for
adapter) is
damaged, replace

The adapter is
damaged. Please
replace it.

Check if there is
power output from
the audion T5.

Check if the
voltage value
between the pins of
oscillator CR1 is

0.20v.

The problem is in
main board, replace
it

.

The audion T58550
or T118050 is
damaged.

The oscillator is
damaged. Replace
it.

The problem can be
solved.

Replace the CPU.

2. No display after turning on:
Y Y Y

N N Y

Y

N

N Y

N

Y Y

N N

No display
after turn on.

Check if the CPU
is fixed correctly.

Take off the CPU,
clean it and fix
well again.

Replace the display
board.

Check the main
board.

Check if the
voltage value
between the pins of
oscillator CR1 is

0.20v.

Change the
oscillator.

Replace the CPU.

The main board is
damaged. Please
replace it.

Displays well when
power on.

The display is
faulty.

Replace the 16
cores wire.

The display can
work normally.

The 16 cores wire
is damaged.

The pins of LCD
are welded bad.

Reweld the pins.

The driver of
display board is

Reweld it.

Change the
LCD.The problem
can be solved.

The LCD is
damaged.

3. Press the keypad the scale can not work:

Y

N

Y

N

Y

N

The scale can not work
when pressing the keys.

To short-circuit the
keypad.

The problem can be
solved.

The membrane
keypad is damaged.

Change the 16 cores
wire.

The problem can be
solved.

The 16 cores wire
is damaged.

Change the CPU.

The problem can be
solved.

The CPU is
damaged.

Change the 40 cores
socket or RX2.

4. Weighing is inaccurate or instable:

Y Y Y

N N N

Y

N

Y

N

Y

N

Weighing is inaccurate
or instable.

Move away the
eyewinker.

Recalibrate the scale.

The problem can be
solved.

Change load cell and
recalibrate.

The problem can be
solved.

The load cell is
damaged.

Check if the working
environment is stable.

The voltage value is
normal.

The battery voltage is
less than 5.4V

Recharge or replace the
battery.

Change to a stable
place.

To use the scale when
the voltage is normal.

There are something
touch the pan or
u

p

-supporter.

Change the main board
and recalibrate.

The problem can be
solved.