HP-41CX Halfnut problem cardreader with Nov64d

[Hiwi]

Hi all,
as stated in the subject i have a problem with a Nov64d module and my cardreader:

The Nov64d has Hepax, CCD-OSX and MATH rampages E and F are free. I tried other configs and modules as well.

If I plug in the cardreader and insert a card i always get a checksum error. I cannot read any card.

I tried another cardreader with Firmware 1F but the behaviour is the same. When i unplug the Nov64d module i can read every card!
I seems to me, that the speed changes a bit (quicker).

This is only on a HP-41CX halfnut, but not on a fullnut machine. I have two halfnuts, for both the same situation.

Can anyone explain that or tell me how to fix it?

Ralf

[Diego Diaz]

Hi Ralf,

This may be related to the differences from Half/Fullnuts power supply. Being the halfnuts a bit weaker than the fullnuts.

The demanding card reader motor can cause a dropout in the power line (V+) affecting the functionality of the NoV-64d and causing noise in the bus, which renders the "CHECKSUM ERR".

Again, I don't have a Card Reader or a Halfnut here, but you can check if the problem persist when configuring your NoV-64d in a Clonix-D fashion; this saves a few mAmps and may help the Card Reader to perform as expected.

Also, trying new fresh batteries or external power will give a glimpse of the power supply behaviour.

Sorry not being of much help on this, I've got very limited resources here. I can offer a much detailed diagnosis once I get back home next month.

Best wishes.

Diego.

[Hiwi]

Hi Diego,
thanks for reply, this is not a big thing, since i am using the cardreader not very often.
In this case i had an old program on mag cards only for calculating LM317 voltage regulators.
I pulled the Nov64d out and could read the cards. Now i put the program on Hepax memory and don't need the cardreader nay more. I only thought the cardreader or the HP-41 may be defective.
Ralf