[time-nuts] bad lcd readout on austron 2100 loran

[Chuck Harris]

The Austron 2100 LCD display plugs into two very long sip strips on the
display panel.  It does not use the pressure connected zebra strips.

However, it does suffer greatly from bad contacts and tin whiskers.  It
should be very carefully removed, and the contact pins should be dampened
with deoxit, or some other contact cleaner/lubricant.  The socket strips
should be blown out with compressed air, and then reassemble.

Another vexing problem with the 2100 family is the keyboard decoder/debounce
circuitry.  As the keypad ages, the contacts get dirty, and the bounce period
increases dramatically.  The keyboard decoder/debounce chips each have a
1uf tantalum capacitor associated with it that is the time constant for the
debounce circuitry.  The key switch contacts should be cleaned, and the
capacitor should be replaced with a 10uf tantalum.  I am not sure how to
clean the switch contacts..., but they should be cleaned.

-Chuck Harris

Daun Yeagley wrote:
> Along the lines of a bad connection, a common problem I have seen with LCD
> displays is the "zebra strip" elastomer connection to the LCD itself.
> Basically, this is an elastomer strip that has conductive stripes and it is
> squeezed between the glass edges of the display and the underlying PC board.
> They are usually captivated by a metal assembly and held in place by bent tabs.
> You would release the tabs to get the parts out, clean them carefully and
> reassemble.  I have repaired a number of various displays this way.
> On a similar note, I see a lot of newer consumer items with LCD's are now just
> gluing a ribbon cable between the display and board.  Problem is that as they
> age, the connections get bad and you start loosing display segments.  I would
> presume that the remedy for this is to clean and re-glue, but I have not yet
> seen a suitable glue for such purposes.  Has anyone else?  If so, I'd sure like
> to know so I can fix a few of them!
> 
> Daun