[time-nuts] 2100f lcd display
george_margetts at nss.net
Tue Apr 26 15:34:31 EDT 2005
I didn't have the guts to pry out the large lcd display on the austron
2100. But I now realize the problem with its display.
Whats happening is noise from the ttl logic is falsely gating the cmos
lcd drivers. This is a common engineering mistake when interfacing ttl
to cmos logic. The recommended fix is to use an HCT part (74HCT240) as
a bridge between logic types. Also I believe pullup resistors were
another recomendation for interfacing ttl to cmos.
Anyway I will keep the net advised as I eliminate noise in the austron
Brooke Clarke wrote:
> Hi George:
> A common problem with the 2100 series units is that the LCD gets loose
> in it's socket.
> Unplug the two front panel ribbon cables, remove 6 screws.
> Have a close look to see how the LCD is relative to the socket, then
> carefully remove and reinstall the LCD.
> Let us know if that fixes it.
> Have Fun,
> Brooke Clarke, N6GCE
> w/Java http://www.PRC68.com
> w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
> george wrote:
> >I just aquired my first Austron 2100F loran frequency monitor via ebay.
> >I'm having trouble reading the display. There is leakage to other
> >segments of the display that should normaly be off.
> >To be most specific when I enter 8888 from the key pad the other blank
> >digits start activating slightly when I enter 88888 all other digits are
> >90% activated.
> > The more segments of the displayed that are active creates more bleed
> >over into the unactive segments at a very consistant amount.
> >I've believe the problem is in the lcd display itself as I've
> >substituted a different cpu/mpu out of my 2100R and the lcd problem
> >still exists.
> >Has anyone noticed even the slightesd leakage into the other segments
> >of there 2100F's lcd display?
> >I believe the ground return pins of the lcd display module itself has
> >high resistance or is opening up completely allowing backfeeding from
> >other segments.
> >time-nuts mailing list
> >time-nuts at febo.com
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