HP-67 2104S02158 - faint display

[albertofenini]

Hello Everyone

does anyone know if the brightness of an HP-67 display can be enhanced ?
We have cleaned this unit which works fine, but the display is by far less bright than the average HP-67 .

We have tested it with different battery packs with the same results.
We have not tested the external battery charger as we are always a little concerned in attaching a charger, although working.

Thanks for any idea you would like to share o suggest !
Take care !

If someone is interested in few pictures, even if it's not finished yet, this is the link : HP-67 2104S02158 - faint display