|Re: OT: Texas SR-52. A great opportunity.|
Message #20 Posted by Eric Smith on 12 Dec 2007, 5:15 a.m.,
in response to message #19 by Etienne Victoria
even when Hp solved this connector issue with the halfnut evolution, the Hp-41C keyboard is still very difficult to repair compared to the Classics series keyboard.
The 41C family both original and halfnut, were designed such that the keyboard repair was very easy. Remove top case, discard, install new top case. It's right in the service manual.
Oh, did you mean that you wanted it to be easy for you to repair? Sorry, that wasn't in the design spec. In fact, it's generally not in the design spec for any consumer electronic product. Consequently, I don't think it's reasonable to criticize the design on that point.
I agree with you that the contacts used in earlier HPs had better long term reliability. They also cost more, both for the contacts and the gold plating of the PCB. The zebra strip was obviously intended to meet the product reliability objective at a lower cost. As far as I know, it did so.
I suspect that the reason for the better contacts in the Classic and Woodstock series was that making consumer products was new to HP at the time, and they didn't have a good feel for how much overengineering was necessary to meet the reliability objective for a product that might be subjected to a fair amount of physical abuse. I don't think it was specifically intended that the Classic series last for more than 30 years, even though they've generally done so.
In the Spice series, they went too far the other way with the press-fit assembly, and had a high defect rate eventually resulting in a redesign.
Edited: 12 Dec 2007, 5:22 a.m.