41c vs 41cx display compatibility

[GreyUser]

You’ve got a bit of a mix up there.

The original 41C lcd driver was pn 00041-80003.

The later board used on all models was pn 00041-60146.

Both driver boards appear to me to be the -80003 variant in the attached photo. That must be a very early CX model, one of the first if those keyboards are all original.

The later -60146 is approximately 2 mm higher than the original -80003 so the lcd’s are not (easily) interchangeable between the two boards but as an assembly (driver board and lcd clipped together), they are interchangeable. That said, the later boards are a very tight squeeze in tall key C’s.

Any 41 that has one or both immovable rocker switches is probably stuck together with crystalized sugar from a pop or other high sugar beverage spill. These are always cleanable in warm water, once the lcd and driver board assembly has been removed. Crystalline sugar can have surprising strength when lodged in key hinges.

To complete the display driver discussion, early tall key C display drivers with the square, molded chip covers require a different value clock timing capacitor. IIRC, it’s discussed in the 41 service manual under revision histories.

Be careful swapping fullnut CX boards, the majority of CX processor boards were built with .050 thick material, not the original .062 thick FR-4. The reason for this change is unknown but I suspect it was a cost savings or wave soldering issue. So, don’t lose or misplace those .015 Teflon washers placed on the lower posts, they are absolutely required. If omitted, you’ll have what you describe, an apparently dead processor board.