HP 41CX math and X memory problems

[rprosperi]

(11-24-2018 09:32 PM)Jlouis Wrote:  Hi all,

I have a 41CX with math, IR printer, Advantage and X memory modules.

The prolems are the the calculator do no find the math and X memory modules.

In cat 2, it does not show these both modules.

In cat 4, there's a DIR EMPTY message.

The math module is ok in my CV. I can not test the X memory due I don't have the X functions module.

When I press Prgm, there are 218 REG, after a reset in the calculator.

I have tried different positions, with and without others modules.

The X-Memory module is never seen in CAT 2. An X-mem module simply adds more extended RAM for the built-in Extended Functions to manage (the CX has the Ext Functions/Memory module built-in).

CAT-4 returns the amount of X-Memory available to the X register. Try this with and then without the X-Mem module inserted and you should see different results. If they are the same then either the module or the slot you are using is bad. Try other slots.

If the Math ROM is not seen in any of the slots, the module is probably bad. The fact that the printer and Adv ROM work confirms those slots are good - try rotating ports and see if there is a pattern.

For both modules, if they have been sitting for a long period, especially not inside a 41C, it's possible oxidation has built-up on the contacts, just like any other device. Try CAREFULLY cleaning the contacts with DeOxit RED (I use Qtips with much of the cotton pulled-off before starting).

It's also possible the 'bad' ports inside need to be cleaned, but do so carefully here as well - the blade you push the module onto is sturdy, but the leads on the folded connector sheet can be torn if they are badly oxidizing.