HP 21 Woodstock Missing Decimal Point

[emece67]

(01-07-2016 08:44 AM)jebem Wrote:  One possible cause for this failure is related to battery leaking corroding the fin LED wires.

If I remember well, it is possible to remove the plastic lens (with great care!) in order to access the actual LED wires and try to repair it.
A microscope is in order here.

Sometimes, inspection with a watchmaker's lens can give a clue if the tiny aerial wire connecting the offending dot to the PCB strip is damaged. If it is still attached to the dot, but otherwise broken or desoldered from the PCB, it may be repairable by soldering a new (thicker) wire to the PCB and soldering it to the remaining tiny wire. Use old Sn/Pb mix to solder, as the tiny wire does not support well the high temperatures needed by modern mixes.

I've repaired some segments in a 25 in such way.

Regards.