Bad HP41 display? Shows @'s and whistles

[Geoff Quickfall]

Sorry, maybe bad news on the LCD panel:

after following Ignacios' continuity check for the LCD solder joints and ensuring good flex contact at top and good zebra at bottom and still resulting in the same display: it will be the display driver on the LCD panel, the two square caps on the panel pre 1980 or the epoxy grey lumps also on the panel post 1980.

A donor panel can be used and easily replace the defective panel if required. If the display is still defective after replacement then it is some where else.

I have seen this on two of the systems I have replaced.

So:

-check all contacts
-check solder joints
-ensure screw posts are not defective
-check zebra strips (done)
-check foam insert on top flex contact for undue compression.
-replace LCD panel

Let us know how it turns out.

Geoff