Problem using 4026 LED display drivers

[frank_uc]

I'm trying to use a pair of 4026 display drivers as shown on page 22 of the interface help section. The two LED displays reset to zero, and pulses are arriving on the "clock" pin, but the display does not change. Any suggestions would be greatly appreciated.

 

[BeanieBots]

Sounds like your reset line is not being taken/held low.
If reset is left floating, it will reset. It must be pulled low.

 

[Michael 2727]

If you touch the CLOCK pin with your finger, and the
clock pin should not be connected to anything else,
and if you are within 1 meter or so of the AC mains,
via a any wiring or appliance. You should get the
display to count @ 50/60 Hz. Your body should act
as an antenna and pick up a small amount of the mains
induced voltage which will/should be enough to drive the
clock input.
You will also see this effect if you touch the probe
lead on a CRO ( oscilloscope )

EDIT
NOTE: The 4026 is a CMOS device and can be damaged
by ESD ( Electrostatic Discharge ) so if you have been
zooming around on a carpeted floor, make sure you
discharge yourself first before touching any ICs, chips etc. (any appliance with a metal case and pluged into a
wall socket should be Earth or Grounded, even when OFF)

 

[craig008]

remember to tie any unused pins on the chips low with a 10k resistor to ground and as beanienots said tie the reset and maybe the clock down with large resistors (10K) low to stop the pins deciding what they want to do.
________
Suzuki sx4