HP 21 Woodstock Missing Decimal Point

[jebem]

I can't find now the references on how to repair these 7-segments displays, but assuming it is failed you may have nothing to lose by trying to repair it.

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.

Another much easier option would be to ask Panamatik for a display replacements here.

But of course if you really are into diy (like myself), you can buy 3 HP QDSP-6064 7-segemnt bubble LED chips, then totally remove the old leds from the PCB and hard-wire thee 3 new chips in place.

I got my HP QDSP-6064 from this German supplier recently at a excellent price, thanks to Harald who has shared the supplier's link.

Please note that I'm not sure if they will work on the HP-2x series as I had not the chance to validate it.

And thinking speed of repair and lower costs, Panamatik offering is a safe bet and very competitive price against any other options that I mentioned.