42s new owner questions

[GreyUser]

(09-25-2021 02:20 PM)Dave Britten Wrote:  Has anybody ever investigated transplanting a display from the more recent 17BII+? Are they even remotely compatible?

They certainly appear to be equals, at least in outward appearance. The original display was made by Epson, obviously still in the business but it’s hard to say if they simply used the original design or tweaked it to be compatible with a totally different processor.

The original multiplexing scheme was likely the cause of the contrast issues since they used 16 rows and 131 columns with the physically driven pins being 16 x 64. This was no doubt due to the Saturn processor pin count and tab packaging limitations. Could you image the reaction when the display design engineer says, “yeah, I really need 64 more pins to do this the the right way”?

FWIW, this was changed in the 48 series by using two external column driver chips so there was no column multiplexing, doubling the pixel on time.

Given the physical layout of the 17Bii+, I suspect it would be quite possible to repurpose the unit into a 42S+ with a new faceplate and keyboard legends by just changing the rom image. I guess that tells you what HP thinks of the market size for an RPN scientific.

Has anybody taken a 17Bii+ apart? Photos?