[time-nuts] Re: HP 10811A unusual appearance

[Keelan Lightfoot]

There's also a hybrid approach, where flex material is used as the inner
layers of a multi-layer PCB, with what is an undoubtedly complicated
multi-step manufacturing process to ensure that the individual rigid PCB
elements can ultimately be routed free of the rigid layer, while the flex
layer remains intact.

I have one example that has seven interconnected rigid elements, and to me
it seems to be a solution in search of a problem. I can't see how the
ridiculous cost of manufacturing such an assembly would offset the cost of
using "traditional" flex and flex connectors.

If the flex portion gets damaged, the entire assembly is junk. In my case,
someone opened the housing containing the rigid/flex monstrosity with a
sharp tool, slicing one of the flex layers, severing over 30 traces that
spanned between two PCBs.

- Keelan

On Wed, Aug 24, 2022 at 11:26 PM Brooke Clarke via time-nuts <
time-nuts at lists.febo.com> wrote:

> Hi Tom:
>
> Interesting comment about flex circuits. Fig 2 in the HPJ article 1981-03
> shows components on the flex. I see flex
> circuits in a lot of  military hardware but they are used to replace
> cables, not hold circuit elements.  For example:
> PSC-2 Digital Communications Terminal (DCT)
> https://prc68.com/I/Images/PSC2-13b.jpg
>
> --
> Have Fun,
>
> Brooke Clarke
> https://www.PRC68.com
> axioms:
> 1. The extent to which you can fix or improve something will be limited by
> how well you understand how it works.
> 2. Everybody, with no exceptions, holds false beliefs.
>