Service manual

PT300, Service Manual
Rev B, October, 2000
18
Low batt indicator won't turn off.
It is possible that the output from the batteries is really low. Look at the cells
and charger circuit for these problems. The low voltage sensor could be out.
The driver for the display could be bad.
Batteries won't charge.
The most common problem is the Fuse, start there. Check for bad batteries.
The charger circuit could be out. Check for bad connections or a defective
charging cable. Look at the power source, whether it's a plug-in transformer or
automotive ignition.
No totalizing.
This may be traced to a defect in a particular scale, or a defect in the
interconnecting cables. In an otherwise properly running scale you need to look
at the serial transmitter and receiver sections. Look for the clock running at the
wrong speed. Try pressing the print button, this should send the local weight
down to the next scale once each time the print button is pressed. Is each scale
in the totalizing mode? Look for the bar on the display. No scale will totalize if
its not stable or if is in an under or over capacity condition. Is the signal getting
from one scale to the next? Look for bad cables or connectors, outside or inside
the scales. The interconnecting wiring inside the scale may be pinched under
the printed circuit board.
Error messages
The following are messages you may see on the display, with the most likely meaning.
-OL Input to A/D converter too low.
OL Input to A/C converter too high.
EEEE Weight not stable while zeroing.
-- A keyboard line is or was in the low state.
=18888= Power-up test pattern