HP41 models and susceptibility for cracked posts

[Nigel Bamber]

I was wondering whether some of the newer built models would have less susceptibility for posts cracking due to changes in design i.e. in the early models the logic board was a separate unit and connected by the zebra connector to the main PCB in the first HP41c units. But in the later CX and CV units they had one PCB Board with all IC hardwired to it , I believe, thus reducing connection difficulties relating to the separate logic board.

If so is it possible to tell which units only had one PCB board, eg maybe all Halfnut units ?

What are the views here ?

Thanks

Nigel

[John Robinson]

Hi Nigel, all 41 calcs are susceptible to screw post breakage, but as you point out, single board versions don't rely on case pressure to keep the contact between several boards. Hence single bpard calcs remain operational even if the screw posts are broken.

All half nuts are single boards, except for the CX models, which have an extra piggy back board, but it doesn't rely on case pressure for good contact between the main board and the piggy back board.

HTH

Cheers,
John

[Etienne Victoria]

Moreover, even halfnut HP41 designs are subject to cracked posts. Even though the boards are not impacted on these models, the module connector sub-assembly is.

It is held tight to the main board by pressure and will fail if the upper screw posts are cracked.

Etienne