Intermec EasyCoder 501 – Service Manual Ed. 7
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Chapter 26 Troubleshooting
26.2 Single Function
Failure
No display function
Possible causes of malfunction:
• No +5V supply. An expedient way of verifying this is to switch
on and off the power. If the fi elds, in which characters are dis-
played, do not appear as black squares for a short moment
during power on, power failure could be the cause of malfunc-
tion. The squares may be weak due to poor contrast or lighting
conditions.
No +5V supply is also indicated by the red LED on the CPU
board and the green LED lamp on the keyboard remaining unlit
after power-on.
• If all other functions are OK, the +5V logic power supply is pre-
sumably also OK, but there may be a defective contact between
the CPU board and the keyboard interface board. Check cable
and connector P-2 on CPU board for possible damage or bad
contact.
• Potentiometer WR-1 for display brightness adjustment may
need to be adjusted.
• A “malfunction” may also be due to the fact that the customized
program sends no messages to the display.
Enter the Test Mode or the Setup Mode. If there is no display
function, the display is defi nitely out of order.
No keyboard reaction
• Check that the transparent plastic cable is not damaged and that
it is positively, inclusive end pins, connected to the keyboard
interface board.
• Normally, the printer should emit a beep each time a key is
pressed. If no beep is heard, but the printer nevertheless reacts
on key depressions, the beeper is either out of order, or disabled
by means of a KEY BEEP statement in the running program.
• If the printer does not react on some or several key depressions
in the setup mode, the keyboard is probably out of order and
needs to be replaced.