I tried this a long time ago and discovered that at least some of the
consumer clocks sold here in the U.S. have only a single segment in the
tens of hours display digit. That's true of the most recent LED clock
I've purchased, so I think it's still common. Don't know how common it
is for LCD clocks, but it's possible that only a single segment is
connected. I think the problem is that the U.S. is a big enough market
that it's cost effective for the manufacturers to make a special version
just for it.

Self-setting "atomic" clocks are getting pretty inexpensive these days,
so I've got two in my shack beside each other, one set to local and one
UTC. The one I use for UTC is made by LaCrosse, and it has a 24 hour
display option.

Roy Lewallen, W7EL

Howard Kowall wrote:
This is not Antenna related,but it applies to Amateur Radio
I had a couple of extra digital clocks at home and I needed two or the ham
shack (Local,UTC)
I wanted both clocks in 24hr mode,so I goggled the clock IC used in the
digital clock,and found most of the using a very general purpose clock IC
and all capable of doing 24hrs format buy a small modification,usually this
mod is just a matter of shorting a couple of pins on the IC
My ic was a LM8560 so all I had to do was jump pins 15 to 28 to make the
clock work in 24hr mode
works great,now all I have to do is glance at the clocks and with an
instance of have both times .I know its an easy conversion to do in you head
but this makes it much more convenient and its a way of using some of the
old stuff around the house and utilizing it rather then throwing it away or
even better having to buy two clocks for the ham shack
Just my contribution to the group
Howard
VE4ISP