Threaded Mode | Linear Mode

Hans Brueggemann · 12-17-2013, 07:06 AM

i recently did a proof of concept of implanting an HP-41CX halfnut time module that i salvaged from my HP-41CX graveyard into an HP-41CL. although being a bit fiddly and a tight fit, the "upgrade" was done in 20 mins. and works as expected.

hans
(no repairable -CXs were harmed during the operation)

Geoff Quickfall · 12-17-2013, 07:59 PM

Excellent!

Is it me, I can't find your tap points on the CX half it board or the connection points on the CL board.

Any chance of more photos with the piezo moved!

Geoff

Hans Brueggemann · (This post was last modified: 01-01-2014 08:53 PM by Hans Brueggemann.)

(12-17-2013 07:59 PM)Geoff Quickfall Wrote: Excellent!

Is it me, I can't find your tap points on the CX half it board or the connection points on the CL board.

Any chance of more photos with the piezo moved!

Geoff

Hi Geoff,
attached picture may help. just use the vias that are close to the respective pads of the main board connector.

hans

Geoff Quickfall · 01-02-2014, 01:45 AM

That, to repeat myself is fantastic. Opens up an entire new set of dynamic timing functions now that the time module is becoming rare.

It will recycle a few half nut dead cx's for harvesting.

Cheers, Geoff

Monte Dalrymple · 01-02-2014, 11:52 PM

Please be very careful when soldering to the vias. Use the minimum amount of time with the heat applied and the minimum amount of solder. The latest boards (version 4) include solder points on the top of the board for this purpose.

Garth Wilson · (This post was last modified: 01-03-2014 01:26 AM by Garth Wilson.)

(01-02-2014 11:52 PM)Monte Dalrymple Wrote: Please be very careful when soldering to the vias. Use the minimum amount of time with the heat applied and the minimum amount of solder. The latest boards (version 4) include solder points on the top of the board for this purpose.

What is the potential failure mechanism? I have designed many very dense multilayer boards for production and never heard of such a problem.

Monte Dalrymple · (This post was last modified: 01-03-2014 02:33 AM by Monte Dalrymple.)

Many PCB failure mechanisms are heat-related:

http://www.edmp.be/uploadedFiles/EDM/Eve...r_EDM2.pdf

Garth Wilson · (This post was last modified: 01-03-2014 05:01 AM by Garth Wilson.)

I'd have to say some of those on that page are kind of like the dangers of a vending machine falling on you. Has it happened? I understand the answer is yes, but doggone it's rare. I have designed many high-density multilayer boards, up to 500 parts and 12 layers, and gotten them into production, and then been the one responsible to fix the rare failing unit, and I've never seen a via or thru-plating fail due to heat. Never. It apparently was an issue before I got into the field in the early 1980's, but that was 30 years ago. If you solder a wire-wrap (or other very thin) wire into a via hole (so it goes all the way through), I expect it would actually improve the reliability.

Is the news saying that halfnuts can now take the CL implant, or only that the cx's time module can be used in place of the plug-in time module? (Either way it's good news.)

Geoff Quickfall · 01-03-2014, 05:07 AM

Fullnut conversions to CL can take a halfnut CX board. Due to the lack of available time modules this is a help

Monte Dalrymple · (This post was last modified: 01-03-2014 05:49 PM by Monte Dalrymple.)

I acknowledge that it seems unlikely to be a problem - if done by someone experienced with soldering and with the right tools. But in my experience with CL buyers, only a subset will fit that mold. I was merely suggesting that people be careful.