HP-41CL New Serial connection and port recovery.

[Diego Diaz]

Hi all,

I know that the HP-41CL is perfectly happy with just three ports available since all ROM PACs can be loaded by SW. Hence, 'sacrificing' port #1 to attach the serial connector is not a big deal.

Nevertheless, I'm a bit too picky when it comes to preserve cosmetics as original as possible.

A while ago, Bob Prosperi sent me a bunch of module housings without connectors. Eventually, some of the shells I use for my projects got broken while opening so these spares are very welcome. However, there are still quite a few that will be unused for the time being.

The idea of giving these empty shells a new life as a detachable serial (and CPLD port) extension for the HP-41CL seemed appealing to me.

First, a Flex PCB is placed into Port #2 top cover. Then a strip of 8 spring loaded contacts is inserted into the empty shell and protrudes from the top cover through a slot. Third, the Flex PCB is connected to the main CL board by means of 8 wires.

Ok, as usual, some pictures will help a lot here...
https://photos.app.goo.gl/63LfDLi2CLKPmUux9

https://photos.app.goo.gl/2qTua6MfTUJ1Tta28

https://photos.app.goo.gl/RKFr3DMKzGxEyDvx8

All this will probably end up just as a 'design exercise' without much interest, by I've enjoyed the process and wanted to share. :-)

Have a nice week!

Diego.